WO2023120533A1 - Binder composition for secondary batteries, electrode sheet, secondary battery, method for producing electrode sheet and method for producing secondary battery - Google Patents

Binder composition for secondary batteries, electrode sheet, secondary battery, method for producing electrode sheet and method for producing secondary battery Download PDF

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WO2023120533A1
WO2023120533A1 PCT/JP2022/046933 JP2022046933W WO2023120533A1 WO 2023120533 A1 WO2023120533 A1 WO 2023120533A1 JP 2022046933 W JP2022046933 W JP 2022046933W WO 2023120533 A1 WO2023120533 A1 WO 2023120533A1
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group
water
active material
secondary battery
soluble polymer
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PCT/JP2022/046933
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French (fr)
Japanese (ja)
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景 河野
一樹 瀧本
郁雄 木下
祥平 片岡
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富士フイルム株式会社
富士フイルム和光純薬株式会社
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Publication of WO2023120533A1 publication Critical patent/WO2023120533A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/24—Homopolymers or copolymers of amides or imides
    • C08L33/26—Homopolymers or copolymers of acrylamide or methacrylamide
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/04—Hybrid capacitors
    • H01G11/06—Hybrid capacitors with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/32—Carbon-based
    • H01G11/38—Carbon pastes or blends; Binders or additives therein
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/84—Processes for the manufacture of hybrid or EDL capacitors, or components thereof
    • H01G11/86—Processes for the manufacture of hybrid or EDL capacitors, or components thereof specially adapted for electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a binder composition for secondary batteries, an electrode sheet, a secondary battery, and a method for manufacturing these electrode sheets and secondary batteries.
  • Secondary batteries typified by lithium-ion secondary batteries, are used as power sources for portable electronic devices such as personal computers, video cameras, and mobile phones. Recently, against the background of the global environmental issue of reducing carbon dioxide emissions, it is becoming popular as a power source for transportation equipment such as automobiles, and as a power storage application such as nighttime power and power generated by natural energy generation.
  • the electrodes (positive electrode and negative electrode) of a lithium ion secondary battery generally have an electrode active material layer (positive electrode active material layer and negative electrode active material layer), and this electrode active material layer absorbs lithium ions during charging and discharging. It also contains releasable electrode active material particles and, if necessary, conductive aids and the like. Electrode active materials, conductive aids, etc. are so-called solid particles, and due to expansion and contraction of the electrode active material particles accompanying charging and discharging (occlusion and release of lithium ions) of the lithium ion secondary battery, the conductive state between the solid particles is impaired. Cheap. If the conduction state is lost, the internal resistance of the battery increases and the battery capacity decreases.
  • Patent Document 1 describes a binder composition for lithium ion secondary battery electrodes containing a particulate polymer and a water-soluble polymer.
  • Patent Document 1 discloses that the water-soluble polymer constituting this composition contains ethylenically unsaturated carboxylic acid monomer units, (meth)acrylamide, N-[2-(dimethylamino)ethyl](meth)acrylamide , N-[3-(dimethylamino)propyl](meth)acrylamide, and a crosslinkable monomer unit other than the carboxylic acid amide monomer unit, containing each in a specific proportion; gas in a lithium ion secondary battery obtained by combining this composition, an electrode active material, and a carboxymethyl cellulose salt and applying it to form an electrode of a lithium ion secondary battery It is described that the generation of is suppressed and the cycle characteristics of the lithium ion secondary battery are improved.
  • lithium-ion secondary batteries using a silicon-based active material as a negative electrode active material, the volume change of the negative electrode active material during charging and discharging is large, and the conduction state ( contact state) is likely to be impaired, so battery performance is likely to deteriorate due to repeated charging and discharging. In other words, there are restrictions on improving cycle characteristics.
  • lithium-ion secondary batteries that use a silicon-based active material as the negative electrode active material are prone to peeling between the negative electrode active material layer and the current collector due to changes in the volume of the negative electrode active material during charging and discharging, so they cannot be used for a long period of time. cannot withstand use.
  • the inventors of the present invention have investigated the effects of conventional electrode binders, such as the binder described in Patent Document 1, on the cycle characteristics of a secondary battery using such a silicon-based active material as a negative electrode active material.
  • conventional binders for electrodes cannot sufficiently respond to the dynamic volume changes of silicon-based active materials that accompany charging and discharging. It has become clear that it is difficult to lead to high levels of
  • the present invention sufficiently enhances the adhesion of the obtained electrode sheet (adhesion between the negative electrode active material layer and the current collector) even when using an electrode active material that undergoes a large volume change during charging and discharging, and obtains It is an object of the present invention to provide a secondary battery binder composition capable of sufficiently improving the cycle characteristics of a secondary battery (sufficiently lengthening the cycle life) of a secondary battery. A further object of the present invention is to provide an electrode sheet and a secondary battery using the binder composition for a secondary battery. A further object of the present invention is to provide a method for manufacturing the electrode sheet and the secondary battery.
  • the present inventors have made various studies on the chemical structure of the polymer that constitutes the binder and the physical properties and shape of the binder. As a result, a polymer particle, a water-soluble polymer having a specific structure, and a water-soluble polymer having a different structure from the water-soluble polymer are combined, and the tensile modulus of the "polymer particle"
  • the binder composition in which the ratio of the tensile elastic moduli of the "water-soluble polymer having a specific structure" exceeds a specific value effectively contributes to excellent adhesion within or between the layers of the secondary battery.
  • the inventors have found that the adhesion of the electrode sheet can be enhanced and the cycle life of the secondary battery can be sufficiently prolonged.
  • the present invention has been completed through further studies based on these findings.
  • Water-soluble polymer (X), water-soluble polymer (Y) and polymer particles are a polymer containing a component represented by the following general formula (B-1) and/or a component represented by the following general formula (B-2).
  • Ratio of the tensile elastic modulus of the water-soluble polymer (X) to the tensile elastic modulus of the coalesced particles (“tensile elastic modulus of the water-soluble polymer (X)”/“tensile elastic modulus of the polymer particles”) is greater than 10, a binder composition for secondary batteries.
  • R 11 to R 13 represent a hydrogen atom, a cyano group or an alkyl group having 1 to 6 carbon atoms
  • R 14 represents a hydrogen atom, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, cyano group, phenyl group, carboxy group, sulfo group, phosphoric acid group or phosphonic acid group
  • L 11 is a single bond, an alkylene group having 1 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom, sulfur An atom, a carbonyl group, an imino group, or a combination of these linking groups.
  • R 21 to R 23 represent a hydrogen atom, a cyano group or an alkyl group having 1 to 6 carbon atoms
  • R 24 represents a hydrogen atom, an acyl group, a hydroxy group, a phenyl group or a carboxy group
  • L 21 represents a single bond, an alkylene group having 1 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom, a sulfur atom, a carbonyl group, an imino group, or a linking group combining these.
  • * indicates a binding site for incorporation into the main chain of the water-soluble polymer (X).
  • ⁇ 2> The binder composition for a secondary battery according to ⁇ 1>, wherein the water-soluble polymer (X) is a polymer containing a component represented by the general formula (B-2).
  • ⁇ 3> The binder composition for a secondary battery according to ⁇ 2>, wherein the water-soluble polymer (X) contains more than 80% by mass of the component represented by the general formula (B-2).
  • ⁇ 4> The binder composition for secondary batteries according to ⁇ 2> or ⁇ 3>, wherein the component represented by the general formula (B-2) contains an acrylamide component.
  • ⁇ 7> The secondary battery according to any one of ⁇ 1> to ⁇ 6>, wherein the water-soluble polymer (Y) contains at least one of carboxymethylcellulose, cellulose nanofiber, hydroxyethylcellulose, hydroxypropylcellulose and xanthan gum.
  • binder composition for ⁇ 8> The binder composition for a secondary battery according to any one of ⁇ 1> to ⁇ 7>, wherein the water-soluble polymer (X) has a weight average molecular weight of 100,000 to 900,000. ⁇ 9>
  • the polymer constituting the polymer particles is a polymer containing at least one of a conjugated diene component, an ethylenically unsaturated carboxylic acid component, a cyano group-containing ethylenic monomer component and an aromatic vinyl monomer component ⁇ 1>
  • ⁇ 12> The binder composition for a secondary battery according to any one of ⁇ 1> to ⁇ 11>, wherein the polymer particles have a glass transition temperature of -50 to 150°C.
  • ⁇ 13> The binder composition for secondary batteries according to any one of ⁇ 1> to ⁇ 12>, further comprising water.
  • ⁇ 14> The binder composition for a secondary battery according to any one of ⁇ 1> to ⁇ 13>, further comprising an active material capable of inserting and releasing ions of a metal belonging to Group 1 or Group 2 of the periodic table.
  • ⁇ 15> The binder composition for secondary batteries according to ⁇ 14>, wherein the active material contains a silicon-based active material.
  • a secondary battery wherein at least one of the positive electrode active material layer and the negative electrode active material layer is a layer formed using the secondary battery binder composition according to ⁇ 14> or ⁇ 15>.
  • a method for producing an electrode sheet comprising forming an electrode active material layer using the binder composition for a secondary battery according to ⁇ 14> or ⁇ 15>.
  • water-soluble polymer means a polymer that has a solubility in water of 10 g/L-H 2 O or more at 20°C, that is, a polymer that dissolves in 1 liter of water at 20°C in an amount of 10 g or more. do.
  • the solubility of the "water-soluble polymer” is preferably 100 g/L-H 2 O or more.
  • a numerical range represented by "to” means a range including the numerical values before and after "to" as lower and upper limits.
  • the representation of a compound, a constituent component, or a substituent means including those in which a part of the structure is changed within the range in which the effects of the present invention are exhibited.
  • substituents e.g., groups expressed as “alkyl group”, “methyl group”, “methyl”, etc.
  • linking groups e.g., "alkylene group”, “methylene group”, “methylene”
  • substituents selected from the substituent group T described later.
  • substituents, etc. when there are multiple substituents or connecting groups (hereinafter referred to as substituents, etc.) indicated by specific symbols or formulas, or when multiple substituents, etc.
  • (meth)acryl means one or both of acryl and methacryl. The same is true for (meth)acrylates.
  • the term "secondary battery” refers to all devices in which ions pass between the positive and negative electrodes via an electrolyte due to charging and discharging, and energy is stored and released at the positive and negative electrodes.
  • the term "secondary battery” in the present invention includes both batteries and capacitors (for example, lithium ion capacitors).
  • the secondary battery of the present invention is preferably used for battery applications (not a capacitor).
  • Secondary batteries can be broadly classified into aqueous secondary batteries and non-aqueous secondary batteries according to the electrolyte used, and non-aqueous secondary batteries are preferred in the present invention.
  • the "aqueous secondary battery” means a secondary battery using an aqueous electrolytic solution as an electrolyte.
  • non-aqueous secondary battery is meant to include non-aqueous electrolyte secondary batteries and all-solid secondary batteries.
  • the "non-aqueous electrolyte secondary battery” means a secondary battery using a non-aqueous electrolyte as an electrolyte.
  • non-aqueous electrolyte means an electrolyte that does not substantially contain water.
  • An electrolytic solution that does not substantially contain water means that the “non-aqueous electrolytic solution” may contain a small amount of water within a range that does not impair the effects of the present invention.
  • the "non-aqueous electrolyte” has a water concentration of 200 ppm (by mass) or less, preferably 100 ppm or less, more preferably 20 ppm or less. It is practically difficult to make the non-aqueous electrolyte completely anhydrous, and usually contains 1 ppm or more of water.
  • the term "all-solid secondary battery” means a secondary battery using a solid electrolyte such as an inorganic solid electrolyte or a solid polymer electrolyte without using a liquid as the electrolyte.
  • this carbon number means the carbon number of the group itself unless otherwise specified in the present invention or this specification.
  • this group when this group is in the form of further having a substituent, it means the number of carbon atoms counted without including the number of carbon atoms of this substituent.
  • the "solid content” used when describing the content or content ratio means components other than water and the liquid medium, which will be described later.
  • the secondary battery binder composition and the electrode sheet of the present invention can sufficiently prolong the cycle life of the resulting secondary battery even when an electrode active material that undergoes a large volume change during charging and discharging is used. Moreover, the electrode sheet of the present invention has excellent adhesion. The secondary battery of the present invention can achieve a sufficiently long cycle life even when using an electrode active material that undergoes a large volume change during charging and discharging. According to the method for producing an electrode sheet of the present invention, the electrode sheet of the present invention can be obtained. Further, according to the method for manufacturing a secondary battery of the present invention, the secondary battery of the present invention can be obtained.
  • FIG. 1 is a vertical cross-sectional view schematically showing the basic lamination structure of one embodiment of the secondary battery according to the present invention.
  • the secondary battery binder composition of the present invention (hereinafter also referred to as "the binder composition of the present invention") comprises a water-soluble polymer (X), a water-soluble polymer (Y), and polymer particles. contains.
  • the binder composition of the present invention is suitable as a material for forming members or constituent layers that constitute a non-aqueous secondary battery, more preferably a non-aqueous electrolyte secondary battery.
  • the binder composition of the invention preferably contains water as the liquid medium.
  • the binder composition of the present invention can be suitably used for forming electrode active material layers in electrodes of secondary batteries.
  • an electrode active material (positive electrode active material or negative electrode active material, collectively referred to as an “active material”) is added to the binder composition of the present invention to form an electrode (positive electrode or negative electrode) of a non-aqueous secondary battery. ) can be used to form an active material layer.
  • the water-soluble polymer (X) and polymer particles contained in the binder composition of the present invention are, for example, formed by mixing the binder composition of the present invention and solid particles (electrode active material, conductive aid, etc.). In the layer, it is believed to function mainly as a binding agent (binder) that binds these solid particles together. It can also function as a binder that binds the current collector and the solid particles. Adsorption of the water-soluble polymer (X) and polymer particles to solid particles and current collectors includes not only physical adsorption but also chemical adsorption (adsorption due to formation of chemical bonds, adsorption due to transfer of electrons, etc.). On the other hand, the water-soluble polymer (Y) contained in the binder composition of the invention is considered to function mainly as a thickener (dispersant) in the binder composition of the invention.
  • the binder composition of the present invention can be used, for example, by preparing an electrode sheet in a form containing an active material and applying it to the electrode of a secondary battery, thereby increasing the adhesion of the electrode sheet and improving the performance of the secondary battery. Cycle characteristics can be improved. Although the reason for this is not clear, it is considered as follows.
  • the binder composition of the present invention is thickened by containing the water-soluble polymer (Y), and the dispersibility of the binder composition is enhanced. Therefore, even in the electrode active material layer formed using this binder composition, solid particles such as water-soluble polymer (X), water-soluble polymer (Y), polymer particles, and active materials are substantially It can be distributed uniformly.
  • the water-soluble polymer (X) interacts with the solid particles and the like, and its physical properties are much harder than those of the polymer particles, thereby suppressing changes in the volume of the electrode active material layer. It is considered that one of the reasons for the improvement of the cycle characteristics is that the conformability and binding property of the polymer particles to the solid particles and the like can be brought out without difficulty.
  • the water-soluble polymer (X) is a polymer (general formula (B -1) and a polymer containing at least one component represented by the following general formula (B-2).
  • the value of the ratio of the tensile elastic modulus of the water-soluble polymer (X) to the tensile elastic modulus of the polymer particles (“tensile elastic modulus of the water-soluble polymer (X)”/“tensile elastic modulus of the polymer particles”) is More than 10 and preferably 12 or more.
  • the ratio of "tensile modulus of water-soluble polymer (X)"/"tensile modulus of polymer particles” is practically 40 or less, preferably 25 or less.
  • R 11 to R 13 each represent a hydrogen atom, a cyano group or an alkyl group having 1 to 6 carbon atoms.
  • This alkyl group having 1 to 6 carbon atoms may be linear or branched.
  • the alkyl group having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 4 carbon atoms, more preferably methyl or ethyl, and still more preferably methyl.
  • a hydrogen atom is preferable as R 11 and R 12 .
  • R 13 is preferably a hydrogen atom or methyl, more preferably a hydrogen atom.
  • the alkyl group in the alkoxy group having 1 to 6 carbon atoms may be linear or branched.
  • the alkoxy group having 1 to 6 carbon atoms is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably methoxy or ethoxy.
  • R 14 is preferably a hydrogen atom, a hydroxy group, methoxy or ethoxy, more preferably a hydrogen atom.
  • L 11 may have a substituent selected from the substituent group T described later, and the substituent is preferably a hydroxy group.
  • RN represents a hydrogen atom or an alkyl group.
  • the chemical formula weight of L 11 is preferably 14-2000, more preferably 14-500, even more preferably 28-200.
  • the alkylene group having 1 to 16 carbon atoms that L 11 may have may be linear or branched.
  • the alkylene group having 1 to 16 carbon atoms is preferably an alkylene group having 1 to 12 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms, still more preferably an alkylene group having 1 to 6 carbon atoms, and 1 to 1 carbon atoms.
  • An alkylene group of 4 is particularly preferred.
  • L 11 is preferably a single bond, methylene, ethylene, propylene, 2-hydroxypropylene or butylene, more preferably a single bond, ethylene or butylene. * indicates a binding site for incorporation into the main chain of the polymer (water-soluble polymer (X)).
  • R 21 to R 23 have the same definitions as R 11 to R 13 above, and preferred forms are also the same. That is, R 21 and R 22 are preferably hydrogen atoms, R 23 is preferably a hydrogen atom or methyl, and more preferably a hydrogen atom.
  • R24 represents a hydrogen atom, an acyl group (alkylcarbonyl group), a hydroxy group, a phenyl group or a carboxy group. As the alkyl group in the acyl group, for example, an alkyl group having 1 to 6 carbon atoms that can be used as R 11 to R 13 can be employed.
  • R 24 is preferably a hydrogen atom or a hydroxy group, more preferably a hydrogen atom.
  • L 21 has the same definition as L 11 above, and preferred forms thereof include the preferred forms of L 11 , more preferably a single bond or ethylene, and still more preferably a single bond. * indicates a binding site for incorporation into the main chain of the polymer (water-soluble polymer (X)).
  • component represented by the general formula (B-1) examples include (meth)acrylic acid component; methyl (meth)acrylate component, ethyl (meth)acrylate component, and propyl (meth)acrylate component. and alkyl (meth)acrylate components such as butyl (meth)acrylate component; 2-hydroxyethyl (meth)acrylate component, 4-hydroxybutyl (meth)acrylate component, 2,3-dihydroxypropyl (meth)acrylate component, etc.
  • hydroxyalkyl (meth)acrylate component alkoxyalkyl (meth)acrylate components such as methoxyethyl (meth)acrylate component and ethoxyethyl (meth)acrylate component, (meth)acrylic acid component, or hydroxyalkyl (meth) ) acrylate components are preferred.
  • Specific examples of the component represented by the general formula (B-2) include (meth)acrylamide component; N-(hydroxyalkyl)(meth) such as N-(2-hydroxyethyl)(meth)acrylamide component
  • An acrylamide component may be mentioned, with a (meth)acrylamide component being preferred, and an acrylamide component being more preferred.
  • the water-soluble polymer (X) preferably contains a component represented by the general formula (B-2). , more preferably an acrylamide component.
  • the content of the acrylamide component in the water-soluble polymer (X) is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 85% by mass or more.
  • the upper limit is not particularly limited, and may be 100% by mass.
  • the water-soluble polymer (X) used in the present invention is a component represented by the general formula (B-1) and/or the general formula (B-2) within a range that does not impair the effects of the present invention. It may contain constituents other than the constituents represented by and examples of such constituents include an acrylonitrile component, an N-vinyl-2-pyrrolidone component and a styrene component, with the acrylonitrile component being preferred.
  • the types of constituent components contained in the water-soluble polymer (X) are not particularly limited, and are preferably 1 to 10 types, more preferably 1 to 5 types, and even more preferably 1 or 2 types. Specific examples of the water-soluble polymer (X) described later describe polymers having one or two types of constituent components.
  • the one-component polymer is polyacrylamide.
  • the content of the component represented by the general formula (B-1) and/or the component represented by the general formula (B-2) is 60% by mass in total. is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 85% by mass or more, still more preferably 90% by mass or more, still more preferably 95% by mass or more, and 100% by mass. good too.
  • the content of the component represented by the general formula (B-1) in the water-soluble polymer (X) is preferably 40% by mass or less, more preferably less than 20% by mass, and even more preferably 15% by mass or less. .
  • the content of the component represented by the general formula (B-2) is preferably 60% by mass or more, and from the viewpoint of further improving adhesion and cycle characteristics, it is 80% by mass. More preferably, it exceeds 85% by mass, and more preferably 85% by mass or more.
  • the water-soluble polymer (X) is a component other than the component represented by the general formula (B-1) and/or the component represented by the general formula (B-2) (that is, the Other than the constituents represented by the general formula (B-1), and the constituents other than the constituents represented by the general formula (B-2)), the general formula (B-2 ) is preferably 65% by mass or more, and more preferably 75% by mass or more from the viewpoint of further improving adhesion and cycle characteristics.
  • the mass ratio of the content of the component represented by the general formula (B-2) to the content of the component represented by the general formula (B-1) (represented by the general formula (B-2)
  • the content of the component represented by the general formula (B-1)/the content of the component represented by the general formula (B-1)) is not particularly limited, and is preferably 99/1 to 60/40.
  • the weight average molecular weight (Mw) of the water-soluble polymer (X) used in the present invention is not particularly limited, and is preferably 100,000 to 900,000, more preferably 200,000 to 500,000, from the viewpoint of improving cycle characteristics. It is preferable that the water-soluble polymer (X) does not have a crosslinked structure, that is, it is a chain polymer.
  • the molecular weight distribution of the water-soluble polymer (X) (also called dispersity, calculated by [weight average molecular weight (Mw)]/[number average molecular weight (Mn)]) is , is preferably 5.0 or less, more preferably 3.0 or less.
  • the practical molecular weight distribution is 1.0 or more.
  • the weight average molecular weight and number average molecular weight of the polymer are measured by gel permeation chromatography (GPC).
  • GPC gel permeation chromatography
  • Molecular weight refers to molecular weight in terms of polyethylene oxide.
  • the values are basically measured according to the method of measurement condition 1 below. However, depending on the type of polymer, an appropriate eluent may be selected and used.
  • Measuring instrument HLC-8220GPC (trade name, manufactured by Tosoh Corporation)
  • Carrier 200 mM sodium nitrate aqueous solution Measurement temperature: 40°C Carrier flow rate: 1.0 ml/min Sample concentration: 0.2% by mass Detector: RI (refractive index) detector If the molecular weight cannot be measured under the measurement condition 1 above, such as when cross-linking is applied, the molecular weight is measured by static light scattering under the measurement condition 2 below.
  • RI reffractive index
  • the water-soluble polymer (X) used in the present invention preferably has a tensile modulus of 3500 MPa or more, preferably 4000 MPa or more, from the viewpoint of effectively suppressing volume change of the electrode active material layer and improving cycle characteristics. is more preferable, 5000 MPa or more is still more preferable, and 6000 MPa or more is particularly preferable. On the other hand, it is practical that the tensile modulus is 15000 MPa or less. In the present invention, the tensile modulus is a value obtained by the method described in Examples below.
  • the water-soluble polymer (X) may further have a substituent in each structure or partial structure described above, and examples of the substituent include substituents selected from the following substituent group T. Further, with respect to each substituent in the water-soluble polymer (X), unless otherwise specified, the description of the corresponding substituent in the following substituent group T can be applied. For each linking group in the water-soluble polymer (X), unless otherwise specified, the description of the linking group obtained by removing the hydrogen bond from the corresponding substituent in the following substituent group T can be applied.
  • Substituent group T - alkyl groups (preferably alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), alkenyl groups (preferably alkenyl groups having 2 to 20 carbon atoms, such as vinyl, allyl, oleyl, etc.), alkynyl groups (preferably alkynyl groups having 2 to 20 carbon atoms, such as ethynyl, butadiynyl, phenylethynyl etc.), cycloalkyl groups (preferably cycloalkyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.), aryl groups (preferably
  • amino (—NH 2 ), N,N-dimethyl amino, N,N-diethylamino, N-ethylamino, anilino, etc.
  • sulfamoyl group (preferably a sulfamoyl group having 0 to 20 carbon atoms, substituted with a group selected from an alkyl group and an aryl group) including groups.
  • sulfamoyl (—SO 2 NH 2 ), N,N-dimethylsulfamoyl, N-phenylsulfamoyl, etc.), acyl groups (alkylcarbonyl groups, alkenylcarbonyl groups, alkynylcarbonyl groups, arylcarbonyl groups and heterocyclic Acyl groups containing carbonyl groups, preferably having 1 to 20 carbon atoms, such as formyl, acetyl, propionyl, butyryl, octanoyl, hexadecanoyl, acryloyl, methacryloyl, crotonoyl, benzoyl, naphthoyl, nicotinoyl, etc.), acyloxy groups (Including an alkylcarbonyloxy group, an alkenylcarbonyloxy group, an alkynylcarbonyloxy group, an arylcarbonyloxy group and a heterocycl
  • the water-soluble polymer (X) used in the present invention can be obtained by a conventional polymer synthesis method.
  • the method and conditions for chain polymerization and the like are not particularly limited, and ordinary methods and conditions can be appropriately applied depending on the purpose.
  • the "water-solubility" of the water-soluble polymer (X) can be controlled by, for example, the types and contents of constituent components.
  • the water-soluble polymer (X) may be used singly or in combination of two or more.
  • the water-soluble polymer (Y) is a water-soluble polymer having a structure different from that of the water-soluble polymer (X) described above, and is used as a thickening agent for slurry for forming an electrode active material layer of a secondary battery.
  • the thickener include cellulose compounds and polysaccharides such as natural polysaccharides.
  • Cellulose compounds include, for example, methylcellulose, ethylcellulose, benzylcellulose, triethylcellulose, cyanoethylcellulose, nitrocellulose, hydroxymethylcellulose, hydroxyethylcellulose (HEC), hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC), hydroxybutylmethylcellulose, carboxy Methylcellulose (CMC), aminomethylhydroxypropylcellulose, aminoethylhydroxypropylcellulose, cellulose nanofiber (CNF), cellulose nanocrystal (CNC) and the like.
  • the cellulose compound may be in the form of a salt such as an ammonium salt, sodium salt, or lithium salt.
  • the water-soluble polymer (Y) preferably contains at least one of carboxymethylcellulose, cellulose nanofibers, hydroxyethylcellulose, hydroxypropylcellulose and xanthan gum.
  • the water-soluble polymer (Y) may be used singly or in combination of two or more.
  • the polymer particles used in the present invention are particulate polymers, and "particulate” may be flat, amorphous, or the like, preferably spherical or granular.
  • the polymer particles are water-insoluble polymers. That is, the polymer particles are polymers that have a solubility in water of less than 10 g/L-H 2 O at 20° C. (no more than 10 g dissolved in 1 liter of water).
  • the tensile elastic modulus of the polymer particles is not particularly limited as long as the "tensile elastic modulus of the water-soluble polymer (X)"/"the tensile elastic modulus of the polymer particles" exceeds 10.
  • the pressure is preferably 100 to 3000 MPa, more preferably 100 to 1000 MPa.
  • the tensile modulus is a value obtained by the method described in Examples below.
  • the glass transition temperature of the polymer particles is not particularly limited, and is preferably -50 to 150°C, more preferably -30 to 100°C, from the viewpoint of improving adhesion of the electrode sheet and cycle characteristics.
  • the polymer particles have two or more glass transition temperatures, all of them are preferably within the above preferred range.
  • the glass transition temperature of the polymer particles When using commercially available polymer particles, the value described in the manufacturer's catalog is adopted as the glass transition temperature of the polymer particles. If the manufacturer's glass transition temperature information is not available or if synthetic polymer particles are used, the glass transition temperature table in the literature POLYMER HANDBOOK 4th, chapter 36 is adopted. When the glass transition temperature is not described in the above document, the glass transition temperature obtained by measuring under the following measurement conditions is adopted.
  • the glass transition temperature (Tg) is calculated by measuring a dry sample of polymer particles with a differential scanning calorimeter: X-DSC7000 (trade name, manufactured by SII Nano Technology Co., Ltd.) under the following measurement conditions. The same sample is measured twice, and the result of the second measurement is adopted. (Measurement condition) Atmosphere in measurement chamber: Nitrogen gas (50 mL/min) Heating rate: 5°C/min Measurement start temperature: -80°C Measurement end temperature: 250°C Sample pan: Aluminum pan Mass of measurement sample: 5 mg Calculation of Tg: Tg is calculated by rounding off the decimal point of the intermediate temperature between the start point and the end point of the drop on the DSC (differential scanning calorimetry) chart.
  • the average particle size (average primary particle size) of the polymer particles is not particularly limited, and is preferably 50 to 300 nm, more preferably 50 to 250 nm, even more preferably 50 to 200 nm.
  • the average particle size of the polymer particles is the value described in the manufacturer's catalog.
  • the average particle size of the polymer particles is the average particle size of the negative electrode active material (volume-based median diameter in water D50 ) can be used.
  • the polymer particles may be either sequentially polymerized polymer particles or chain polymerized polymer particles, preferably chain polymerized polymer particles.
  • the chain polymer particles may be homopolymers or copolymers.
  • the polymerization form of the copolymer may be either random or block.
  • Constituents of the polymer particles (chain polymerization polymer) include, for example, a conjugated diene component, an aromatic vinyl monomer component, an ethylenically unsaturated carboxylic acid component, a cyano group-containing ethylenic monomer component, and an ethylenically unsaturated carboxylic acid ester component.
  • the and fluorinated vinyl monomer components and preferably contain at least one of a conjugated diene component, an ethylenically unsaturated carboxylic acid component, a cyano group-containing ethylenic monomer component and an aromatic vinyl monomer component.
  • the polymer particles preferably have a conjugated diene component and an aromatic vinyl monomer component among the above components.
  • the aromatic vinyl monomer component means a component derived from a monomer having a carbon-carbon double bond (preferably one or two, more preferably one) and an aryl group (preferably one).
  • the ethylenically unsaturated carboxylic acid component means a component derived from a monomer having a carbon-carbon double bond (preferably one) and a carboxy group (preferably one or two), and a cyano group-containing ethylenic
  • a monomer component means a component derived from a monomer having a carbon-carbon double bond (preferably one) and a cyano group (preferably one or two, more preferably one), and an ethylenically unsaturated carboxylic acid.
  • the acid ester component means a monomer-derived component having a carbon-carbon double bond (preferably one) and a carboxylic acid ester site (esterified carboxy group) (preferably one), and vinyl fluoride
  • a monomer component means an ethylene-derived component having 1 to 4 (preferably 2) fluorine atoms.
  • the "carbon-carbon double bond" above does not include the carbon-carbon double bond of the aromatic ring.
  • Conjugated dienes leading to the conjugated diene component include, for example, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene and 2-chloro-1,3 - Aliphatic conjugated dienes such as butadiene.
  • aromatic vinyl monomers leading to aromatic vinyl monomer components include styrene, ⁇ -methylstyrene, 4-tert-butylstyrene, 4-tert-butoxystyrene, vinyltoluene (3-vinyltoluene, 4-vinyltoluene).
  • Ethylenically unsaturated carboxylic acids leading to the ethylenically unsaturated carboxylic acid component include, for example, (meth)acrylic acid, maleic acid, itaconic acid and fumaric acid.
  • Examples of the cyano group-containing ethylenic monomer leading to the cyano group-containing ethylenic monomer component include (meth)acrylonitrile, ⁇ -chloroacrylonitrile, ⁇ -ethylacrylonitrile and vinylidene cyanide.
  • Examples of the ethylenically unsaturated carboxylic acid ester leading to the ethylenically unsaturated carboxylic acid ester component include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, Examples include (meth)acrylic acid alkyl esters such as hexyl (meth)acrylate, octyl (meth)acrylate and 2-ethylhexyl (meth)acrylate.
  • Examples of the vinyl fluoride monomer that leads to the vinyl fluoride monomer component include vinylidene fluoride.
  • the polymer particles used in the present invention can be obtained by a conventional polymer synthesis method.
  • the method and conditions for chain polymerization and the like are not particularly limited, and ordinary methods and conditions can be appropriately applied depending on the purpose.
  • the polymer particles may be particles obtained by subjecting the above-described successively polymerized polymer particles and chain polymerized polymer particles to modification treatment such as carboxy modification.
  • the method and conditions for modification treatment are not particularly limited, and conventional methods can be used.
  • the solubility in water, tensile modulus, glass transition temperature and average particle size of the polymer particles can be adjusted by, for example, the types and contents of constituents in the polymer.
  • polymeric particles include styrene/butadiene copolymers, acrylic polymers and poly(vinylidene fluoride), with styrene/butadiene copolymers being preferred.
  • a styrene/butadiene copolymer means a copolymer having the above aromatic vinyl monomer component and the above conjugated diene component, and may be a modified copolymer such as a carboxy-modified copolymer.
  • polymer particles may be used singly or in combination of two or more.
  • the binder composition of the present invention may contain other polymers commonly used as binders for batteries.
  • the total proportion of the water-soluble polymer (X), water-soluble polymer (Y) and polymer particles in all polymers contained in the binder composition of the present invention is preferably 80% by mass or more, and 90% by mass. The above is more preferable, 95% by mass or more is still more preferable, and 99% by mass or more is particularly preferable.
  • all of the polymers contained in the binder composition of the present invention are water-soluble polymer (X), water-soluble polymer (Y) and polymer particles.
  • the mass ratio of the water-soluble polymer (X), the water-soluble polymer (Y), and the polymer particles is not particularly limited, and is preferably 10-80:10-80:10-50, more preferably 20-70:20-70:10-30.
  • the binder composition of the present invention preferably contains water as a liquid medium.
  • the content of water in the binder composition of the present invention is not particularly limited, and can be, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, and still more preferably 40% by mass. It is at least 50% by mass, particularly preferably at least 50% by mass.
  • the binder composition of the present invention may contain water in an amount of 60% by mass or more, 70% by mass or more, or 80% by mass or more. On the other hand, it is practical that the water content in the binder composition of the present invention is 99.5% by mass or less.
  • the binder composition of the present invention may contain a liquid medium other than water.
  • Liquid media other than water include, for example, organic solvents that mix with water without phase separation (hereinafter referred to as water-soluble organic solvents), such as N-methylpyrrolidone, methanol, ethanol, and acetone. , tetrahydrofuran and the like are preferred.
  • the contents of the water-soluble polymer (X), the water-soluble polymer (Y) and the polymer particles in the binder composition of the present invention may be appropriately set according to the purpose.
  • the total content of the water-soluble polymer (X), water-soluble polymer (Y) and polymer particles in the binder composition can be 0.5 to 50% by mass, preferably 5 to 30%. % by mass, more preferably 10 to 20% by mass.
  • the binder composition of the present invention contains water-soluble polymer (X), water-soluble polymer (Y), polymer particles, water, liquid media other than water, and other components depending on the purpose. be able to.
  • Other components include, for example, polyhydric alcohols (alcohols having two or more hydroxy groups).
  • the binder composition of the present invention can also be prepared by diluting a synthetic solution of the water-soluble polymer (X), water-soluble polymer (Y) and polymer particles. Therefore, the binder composition of the present invention contains the water-soluble polymer (X), the water-soluble polymer (Y), and the compounds used in the synthesis of the polymer particles or by-products after the reaction thereof. good too.
  • the binder composition of the present invention contains the water-soluble polymer (X), the water-soluble polymer (Y) and polymer particles, and in addition, ions of metals belonging to Group 1 or Group 2 of the periodic table. can contain an active material capable of intercalating and releasing
  • the case where the binder composition of the present invention contains an active material is particularly referred to as the electrode composition of the present invention.
  • the electrode composition of the present invention may further contain a conductive aid and other additives as required.
  • the active material may be a positive electrode active material or a negative electrode active material. When the electrode composition contains a positive electrode active material, the electrode composition can be used as slurry for forming a positive electrode active material layer of a secondary battery.
  • the composition for electrodes when the composition for electrodes contains a negative electrode active material, the composition for electrodes can be used as slurry for forming a negative electrode active material layer.
  • the secondary battery binder composition can be applied to either a positive electrode or a negative electrode composition, but it is preferably used for a negative electrode, and particularly preferably used for a negative electrode composition containing a silicon-based active material. .
  • the active material, conductive aid, and other additives are not particularly limited, and may be appropriately selected and used from those commonly used in secondary batteries according to the purpose.
  • the content of the water-soluble polymer (X), the water-soluble polymer (Y) and the polymer particles in the electrode composition of the present invention is not particularly limited, and is 0.5 in total with respect to the total solid content. ⁇ 30% by mass is preferred, 1.0 to 20% by mass is more preferred, 1.5 to 15% by mass is even more preferred, and 2.5 to 10% by mass is particularly preferred.
  • the mass ratio of the water-soluble polymer (X), the water-soluble polymer (Y), and the polymer particles is not particularly limited, and is preferably 10-80:10-80:10-50, more preferably 20-70:20-70:10-30.
  • the positive electrode active material may be any active material capable of inserting and releasing ions of metals belonging to Group 1 or Group 2 of the periodic table, and among these, those capable of reversibly inserting and releasing lithium ions are preferable.
  • the material is not particularly limited as long as it has the above properties, and may be a transition metal oxide, an organic substance, an element such as sulfur that can be combined with Li, a compound of sulfur and a metal, or the like. Among them, it is preferable to use a transition metal oxide as the positive electrode active material. objects are more preferred.
  • the element M b (an element of group 1 (Ia) of the periodic table other than lithium, an element of group 2 (IIa) of the periodic table, Al, Ga, In, Ge, Sn, Pb, Sb) is added to the transition metal oxide. , Bi, Si, P or B) may be mixed.
  • the mixing amount of the element Mb is preferably 0 to 30 mol % with respect to 100 mol % of the transition metal element M a . It is more preferable to synthesize by mixing so that the molar ratio of Li to the transition metal element M a (Li/M a ) is 0.3 to 2.2.
  • transition metal oxide examples include (MA) a transition metal oxide having a layered rock salt structure, (MB) a transition metal oxide having a spinel structure, (MC) a lithium-containing transition metal phosphate compound, (MD ) lithium-containing transition metal halide phosphate compounds and (ME) lithium-containing transition metal silicate compounds.
  • transition metal oxides having a layered rocksalt structure include LiCoO 2 (lithium cobalt oxide [LCO]), LiNi 2 O 2 (lithium nickel oxide), and LiNi 0.85 Co 0.10 Al 0.85.
  • 05O2 lithium nickel cobalt aluminum oxide [NCA]
  • NCA lithium nickel cobalt aluminum oxide
  • NMC lithium nickel manganese cobaltate
  • LiNi0.5Mn0.5O2 lithium manganese nickelate
  • transition metal oxides having a spinel structure include LiMn 2 O 4 (LMO), LiCoMnO 4 , Li 2 FeMn 3 O 8 , Li 2 CuMn 3 O 8 , Li 2 CrMn 3 O 8 and Li 2NiMn3O8 .
  • Examples of (MC) lithium-containing transition metal phosphate compounds include olivine-type iron phosphates such as LiFePO 4 and Li 3 Fe 2 (PO 4 ) 3 , iron pyrophosphates such as LiFeP 2 O 7 , and LiCoPO 4 . and monoclinic Nasicon-type vanadium phosphates such as Li 3 V 2 (PO 4 ) 3 (lithium vanadium phosphate).
  • lithium-containing transition metal halogenated phosphate compounds include iron fluorophosphates such as Li 2 FePO 4 F, manganese fluorophosphates such as Li 2 MnPO 4 F, and Li 2 CoPO 4 F. and other cobalt fluoride phosphates.
  • Lithium-containing transition metal silicate compounds include, for example, Li 2 FeSiO 4 , Li 2 MnSiO 4 and Li 2 CoSiO 4 .
  • transition metal oxides having a (MA) layered rocksalt structure are preferred, and LCO or NMC is more preferred.
  • the shape of the positive electrode active material is not particularly limited, and is preferably particulate.
  • the average particle diameter (volume-based median diameter D50) of the positive electrode active material is not particularly limited. For example, it can be 0.1 to 50 ⁇ m.
  • it may be prepared by a conventional method using a pulverizer or a classifier. A method for preparing a negative electrode active material having a predetermined particle size, which will be described later, can also be applied.
  • the positive electrode active material obtained by the calcination method may be washed with water, an acidic aqueous solution, an alkaline aqueous solution, an organic solvent, or the like before use.
  • the chemical formula of the compound obtained by the above firing method can be calculated by inductively coupled plasma (ICP) emission spectrometry as a measurement method and from the difference in mass of the powder before and after firing as a simple method.
  • ICP inductively coupled plasma
  • the surface of the positive electrode active material may be surface-coated with an oxide such as another metal oxide, a carbon-based material, or the like.
  • an oxide such as another metal oxide, a carbon-based material, or the like.
  • a surface coating material that can be used for coating the surface of the negative electrode active material described later can be used.
  • the surface of the positive electrode active material may be surface-treated with sulfur or phosphorus.
  • the particle surface of the positive electrode active material may be surface-treated with actinic rays or an active gas (plasma, etc.) before and after the surface coating.
  • the said positive electrode active material may be used individually by 1 type, or may be used in combination of 2 or more type.
  • the mass (mg) (basis weight) of the positive electrode active material per unit area (cm 2 ) of the positive electrode active material layer is not particularly limited. It can be determined appropriately according to the designed battery capacity.
  • the content of the positive electrode active material in the electrode composition of the present invention is not particularly limited, and is preferably 10 to 99% by mass, more preferably 30 to 98% by mass, more preferably 50 to 97% by mass, based on the total solid content. % is more preferred, and 55 to 95% by mass is particularly preferred.
  • the negative electrode active material may be an active material capable of inserting and releasing metal ions (preferably lithium ions) belonging to Group 1 or Group 2 of the periodic table, and in particular, capable of reversibly intercalating and deintercalating lithium ions. things are preferred.
  • the material is not particularly limited as long as it has the above properties. Carbonaceous materials, silicon-based materials (meaning materials containing silicon element), tin-based materials (meaning materials containing tin element) ), metal oxides, metal composite oxides, elemental lithium, lithium alloys, and the like. Among them, a carbonaceous material or a silicon-based material is preferably used from the viewpoint of reliability.
  • a carbonaceous material used as a negative electrode active material is a material that is substantially made of carbon.
  • carbon black such as acetylene black
  • graphite naturally graphite such as flaky graphite and massive graphite, artificial graphite such as vapor-grown graphite and fibrous graphite, expanded graphite obtained by special processing of flaky graphite, etc.
  • activated carbon carbon fiber, coke, soft carbon, hard carbon, and carbonaceous materials obtained by baking various synthetic resins such as PAN (polyacrylonitrile)-based resins and furfuryl alcohol resins.
  • various carbon fibers such as PAN-based carbon fiber, cellulose-based carbon fiber, pitch-based carbon fiber, vapor growth carbon fiber, dehydrated PVA (polyvinyl alcohol)-based carbon fiber, lignin carbon fiber, vitreous carbon fiber and activated carbon fiber. , mesophase microspheres, graphite whiskers and tabular graphite.
  • Tin-based materials (tin-based active materials) used as negative electrode active materials include, for example, Sn, SnO, SnO 2 , SnS, and SnS 2 .
  • the metal oxide and metal composite oxide used as the negative electrode active material are not particularly limited as long as they are oxides capable of inserting and releasing ions of metals belonging to Group 1 or Group 2 of the periodic table.
  • oxides include oxides of metal elements (metal oxides) and oxides of semimetal elements (semimetal oxides).
  • Metal composite oxides include composite oxides of metal elements, Composite oxides with metal elements and composite oxides with metalloid elements are included. As these metal oxides and metal composite oxides, amorphous oxides are preferred, and chalcogenides, which are reaction products of metal elements and Group 16 elements of the periodic table, are also preferred.
  • amorphous as used herein means a broad scattering band having an apex in the region of 20° to 40° in terms of 2 ⁇ value in an X-ray diffraction method using CuK ⁇ rays, and a crystalline diffraction line.
  • amorphous oxides and chalcogenides include Ga2O3 , GeO, PbO, PbO2 , Pb2O3 , Pb2O4 , Pb3O4 , Sb2O3 , Sb2O 4 , Sb2O8Bi2O3 , Sb2O8Si2O3 , Sb2O5 , Bi2O3 , Bi2O4 , GeS , PbS , PbS2 , Sb2S3 and Sb2S 5 is preferred.
  • the metal (composite) oxide and the chalcogenide preferably contain at least one of titanium and lithium as a constituent component from the viewpoint of high current density charge/discharge characteristics.
  • lithium-containing metal composite oxides include composite oxides of lithium oxide and the above metal (composite) oxides or chalcogenides, more specifically Li 2 SnO 2 . mentioned.
  • the negative electrode active material contains a titanium element. More specifically, TiNb 2 O 7 (niobium titanate [NTO]) and Li 4 Ti 5 O 12 (lithium titanate [LTO]) have small volume fluctuations when absorbing and desorbing lithium ions, and are therefore suitable for rapid charging. It is preferable in that the discharge characteristics are excellent, the deterioration of the electrode is suppressed, and the cycle characteristics of the lithium ion secondary battery can be improved.
  • the lithium alloy as the negative electrode active material is not particularly limited as long as it is an alloy normally used as a negative electrode active material for secondary batteries, and examples thereof include lithium aluminum alloys.
  • the silicon - based material is a negative electrode active material containing a silicon element. , manganese, nickel, copper or lanthanum containing silicon-containing alloys (e.g. LaSi2 , VSi2 ), or structured active materials (e.g. LaSi2 /Si), as well as the metal oxides and metal composites mentioned above. Examples include oxides or composite oxides containing silicon element in the description of oxides, and active materials containing silicon element and tin element such as SnSiO 3 and SnSiS 3 . SiO x itself can be used as a negative electrode active material (semimetal oxide), and since Si is generated by the operation of the battery, it is used as an active material (precursor material thereof) capable of forming an alloy with lithium. be able to.
  • the negative electrode active material is preferably a negative electrode active material capable of forming an alloy with lithium.
  • the negative electrode active material capable of forming an alloy with lithium is not particularly limited as long as it is commonly used as a negative electrode active material for secondary batteries. Examples of such an active material include the aforementioned negative electrode active material containing silicon element and/or tin element, and metals such as Al and In.
  • a silicon-based active material is preferable in terms of enabling a higher battery capacity, and a silicon-based active material containing 40 mol % or more of the total constituent elements is more preferable.
  • a negative electrode containing a negative electrode active material capable of forming an alloy with lithium for example, a Si negative electrode containing a silicon-based active material, a Sn negative electrode containing a tin-based active material
  • a negative electrode active material capable of forming an alloy with lithium for example, a Si negative electrode containing a silicon-based active material, a Sn negative electrode containing a tin-based active material
  • a carbonaceous material Graphite, carbon black, etc.
  • the surface of the negative electrode active material may be surface-coated with an oxide such as another metal oxide, a carbon-based material, or the like (hereinafter, surface-coated with a carbon-based material is referred to as “carbon-coated”. may be stated).
  • the surface coating material include metal oxides containing Ti, Nb, Ta, W, Zr, Al, Si or Li. Specific examples include titanate spinel, tantalum-based oxides, niobium-based oxides, lithium niobate-based compounds, and more specifically Li 4 Ti 5 O 12 , Li 2 Ti 2 O 5 , LiTaO.
  • Carbon-based materials such as C, SiC, and carbon-added silicon oxide can also be used as the surface coating material.
  • the surface of the negative electrode active material may be surface-treated with sulfur or phosphorus.
  • the surface of the particles of the negative electrode active material may be surface-treated with actinic rays or an active gas (such as plasma) before and after the surface coating.
  • the negative electrode active material may be doped with a metal element.
  • the doped metal element is preferably at least one of Li, Ni and Ti, more preferably Li.
  • a silicon-based active material as the negative electrode active material, and silicon oxide (SiO x (0 ⁇ x ⁇ 1.5)) or carbon-coated silicon oxide (carbon-coated SiO x ( 0 ⁇ x ⁇ 1.5)), more preferably carbon-coated silicon oxide.
  • the carbon-coated silicon oxide may be further doped with a metal element.
  • the ratio of the carbon element content in the carbon-coated silicon oxide is not particularly limited, and is preferably 0.5 to 5% by mass, more preferably 1 to 3% by mass. Commercially available silicon oxide or carbon-coated silicon oxide may be used.
  • Carbon-coated silicon oxide can also be prepared by carbon-coating silicon oxide, for example, with reference to JP-A-2019-204686.
  • the content of silicon oxide or carbon-coated silicon oxide in the negative electrode active material is not particularly limited, and can be, for example, 10 to 90% by mass, preferably 10 to 50% by mass, more preferably 15 to 40% by mass. preferable.
  • a silicon-based material doped with a metal element is preferably used as the negative electrode active material, and a silicon-based material doped with at least one of Li, Ni and Ti is more preferable, and Li is doped. Further preferred are silicon-based materials. Silicon oxide or carbon-coated silicon oxide is preferable as the silicon-based material to be doped with a metal element. As the silicon oxide doped with a metal element and the silicon oxide doped with both a metal element and a carbon coat, commercially available products may be used.
  • doping a metal element into silicon oxide or carbon-coated silicon oxide Alternatively, it can be prepared by doping silicon oxide with a metal element and, if necessary, further applying a carbon coat.
  • the phrase “both doped with a metal element and carbon-coated” means a product that has been doped with a metal element and then subjected to a carbon coating treatment, and a product that has been subjected to a carbon coating treatment and then subjected to a metal coating treatment. It is used in the sense of including both elements doped with an element.
  • the shape of the negative electrode active material is not particularly limited, and is preferably particulate.
  • the average particle diameter (volume-based median diameter D50) of the negative electrode active material is preferably 0.1 to 60 ⁇ m.
  • the average particle size is more preferably 5 to 20 ⁇ m.
  • it can be prepared by a conventional method using a pulverizer or a classifier. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a whirling jet mill, a sieve, or the like is preferably used.
  • wet pulverization can also be performed in which an organic solvent such as water or methanol is allowed to coexist.
  • Classification is preferably carried out in order to obtain a desired particle size.
  • the classification method is not particularly limited, and a sieve, an air classifier, or the like can be used as desired. Both dry and wet classification can be used.
  • the average particle size of the negative electrode active material is the value described in the manufacturer's catalog.
  • the negative electrode active material is dispersed in water and measured with a laser diffraction/scattering particle size distribution analyzer (for example, HORIBA's Particle LA -960V2 (trade name)) is used (volume-based median diameter D50 in water) obtained by measurement.
  • a laser diffraction/scattering particle size distribution analyzer for example, HORIBA's Particle LA -960V2 (trade name)
  • volume-based median diameter D50 in water obtained by measurement.
  • a negative electrode active material may be used individually by 1 type, or may be used in combination of 2 or more type. Among them, a combination of a silicon-based active material and a carbonaceous material is preferable, a combination of a silicon-based active material and graphite is more preferable, and a combination of silicon oxide or carbon-coated silicon oxide and graphite is even more preferable.
  • the silicon oxide and carbon-coated silicon oxide may be silicon oxide doped with a metal element and silicon oxide both doped with a metal element and carbon-coated, respectively, as described above.
  • the metal element to be doped is preferably at least one of Li, Ni and Ti, more preferably Li.
  • the mass ratio of the silicon-based active material to graphite is preferably 2 or less, more preferably 1 or less, and even more preferably 0.5 or less. Although there is no particular lower limit for the mass ratio of the silicon-based active material to graphite, it is practically 0.05 or more.
  • the mass (mg) (basis weight) of the negative electrode active material per unit area (cm 2 ) of the negative electrode active material layer is not particularly limited. It can be determined appropriately according to the designed battery capacity.
  • the content of the negative electrode active material in the electrode composition of the present invention is not particularly limited, and is preferably 10 to 99% by mass, more preferably 30 to 98% by mass, based on the total solid content. 45 to 97 mass % is more preferred, and 55 to 95 mass % is particularly preferred.
  • the negative electrode active material layer when the negative electrode active material layer is formed by charging the battery, ions of a metal belonging to Group 1 or Group 2 of the periodic table generated in the secondary battery are used instead of the negative electrode active material. can be done.
  • a negative electrode active material layer can be formed by combining this ion with an electron and depositing it as a metal.
  • the electrode composition of the present invention can also contain a conductive aid, and it is particularly preferred that the silicon-based active material as the negative electrode active material is used in combination with the conductive aid.
  • a conductive aid there are no particular restrictions on the conductive aid, and any commonly known conductive aid can be used.
  • carbon blacks such as acetylene black, ketjen black, furnace black, etc.
  • amorphous carbon such as needle coke
  • carbon fibers such as vapor-grown carbon fiber or carbon nanotube, graphene or fullerene, etc.
  • metal powders and fibers such as copper and nickel
  • conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene and polyphenylene derivatives.
  • a conductive aid that does not cause insertion and release of Li during charging and discharging of the battery and does not function as an active material when used in combination, among the above conductive aids, a conductive aid that does not cause insertion and release of Li during charging and discharging of the battery and does not function as an active material. and Therefore, among the conductive aids, those that can function as an active material in the active material layer during charging and discharging of the battery are classified as active materials rather than conductive aids. Whether or not it functions as an active material when the battery is charged/discharged is not univocally determined by the combination with the active material.
  • a conductive support agent may be used individually by 1 type, or may be used in combination of 2 or more type.
  • the content of the conductive aid in the electrode composition of the present invention is preferably 0.5 to 60% by mass, more preferably 1.0 to 50% by mass, more preferably 1.5 to 1.5% by mass, based on the total solid content. 40% by mass is more preferred, and 2.5 to 35% by mass is particularly preferred.
  • the shape of the conductive aid is not particularly limited, and is preferably particulate.
  • the average particle diameter (volume-based median diameter D50) of the conductive aid is not particularly limited, and is preferably 0.01 to 50 ⁇ m, more preferably 0.02 to 10.0 ⁇ m.
  • the average particle diameter of the conductive additive adopts the value described in the manufacturer's catalog.
  • the average particle size of the conductive agent is the average particle size of the negative electrode active material (volume-based median diameter in water D50 ) can be used.
  • the electrode composition of the present invention may optionally contain lithium salts, ionic liquids, thickeners, antifoaming agents, leveling agents, dehydrating agents, antioxidants, etc. as other components in addition to the above components. can be done.
  • conductive aids, and other additives for example, International Publication No. 2019/203334, Japanese Patent Application Laid-Open No. 2015-46389, etc. can be referred to.
  • the binder composition for a secondary battery of the present invention contains a water-soluble polymer (X), a water-soluble polymer (Y), polymer particles, preferably water, and optionally any other component such as It can be prepared as a mixture, preferably as a slurry, by mixing with various commonly used mixers.
  • a water-soluble polymer X
  • Y water-soluble polymer
  • polymer particles preferably water
  • any other component such as It
  • It can be prepared as a mixture, preferably as a slurry, by mixing with various commonly used mixers.
  • an active material and, optionally, a conductive aid are mixed.
  • the mixing method is not particularly limited, and may be mixed all at once or sequentially.
  • a mixture obtained by mixing a plurality of components may be mixed with other components, for example, water-soluble polymer (X), water-soluble polymer (Y), active material, conductive aid and water After mixing, water and polymer particles may be added and further mixed to obtain a secondary battery binder composition (electrode composition).
  • X water-soluble polymer
  • Y water-soluble polymer
  • active material active material
  • conductive aid conductive aid
  • water and polymer particles may be added and further mixed to obtain a secondary battery binder composition (electrode composition).
  • the electrode sheet of the present invention has a layer (electrode active material layer, ie, negative electrode active material layer or positive electrode active material layer) formed using the electrode composition of the present invention.
  • the electrode sheet of the present invention may be any electrode sheet having an electrode active material layer. A sheet formed only of an active material layer (negative electrode active material layer or positive electrode active material layer) may be used. This electrode sheet is usually a sheet having a structure in which an electrode active material layer is laminated on a current collector.
  • the electrode sheet of the present invention may have other layers such as a protective layer such as a release sheet and a coat layer.
  • the electrode sheet of the present invention is a material constituting a negative electrode active material layer or a positive electrode active material layer of a secondary battery, or a laminate (negative electrode layer) of a negative electrode current collector and a negative electrode active material layer, or a positive electrode current collector and a positive electrode. It can be suitably used as a laminate of active material layers (positive electrode layer).
  • the current collector constituting the electrode sheet of the present invention is an electron mediator and is usually in the form of a film sheet.
  • the current collector can be appropriately selected according to the active material.
  • the constituent material of the positive electrode current collector include aluminum, aluminum alloys, stainless steel, nickel, and titanium, with aluminum or aluminum alloys being preferred.
  • the positive electrode current collector include those obtained by treating the surface of aluminum or stainless steel with carbon, nickel, titanium or silver to form a coat layer (thin film).
  • Materials constituting the negative electrode current collector include aluminum, copper, copper alloys, stainless steel, nickel, and titanium, with aluminum, copper, copper alloys, and stainless steel being preferred.
  • the negative electrode current collector include those obtained by treating the surface of aluminum, copper, copper alloy or stainless steel with carbon, nickel, titanium or silver to form a coat layer (thin film).
  • the thickness of the positive electrode active material layer constituting the electrode sheet of the present invention is not particularly limited, and can be, for example, 5 to 500 ⁇ m, preferably 20 to 200 ⁇ m. Moreover, the thickness of the positive electrode current collector constituting the electrode sheet of the present invention is not particularly limited, and can be, for example, 10 to 100 ⁇ m, preferably 10 to 50 ⁇ m.
  • the thickness of the negative electrode active material layer constituting the electrode sheet of the present invention is not particularly limited, and can be, for example, 5 to 500 ⁇ m, preferably 20 to 200 ⁇ m. Moreover, the thickness of the negative electrode current collector constituting the electrode sheet of the present invention is not particularly limited, and can be, for example, 10 to 100 ⁇ m, preferably 10 to 50 ⁇ m.
  • the electrode sheet of the present invention can be obtained by forming an electrode active material layer using the electrode composition of the present invention.
  • the electrode sheet of the present invention can be produced by forming a film using the electrode composition of the present invention.
  • a current collector or the like is used as a base material, and the electrode composition of the present invention is applied thereon (may be via another layer) to form a coating film, which is then dried.
  • an electrode sheet having an active material layer (coated and dried layer) on a substrate can be obtained.
  • the secondary battery of the present invention can be obtained by incorporating the electrode sheet obtained by the electrode sheet manufacturing method into at least one of the electrodes (positive electrode and negative electrode) of the secondary battery.
  • the secondary battery of the present invention at least one of the positive electrode active material layer and the negative electrode active material layer is a layer formed using the electrode composition of the present invention.
  • the secondary battery of the present invention has a positive electrode active material layer, a separator, and a negative electrode active material layer in this order, and at least one of the positive electrode active material layer and the negative electrode active material layer comprises the This is a layer formed using the electrode composition of
  • the secondary battery of the present invention will be described by taking the form of a non-aqueous electrolyte secondary battery as an example, but the secondary battery of the present invention is not limited to a non-aqueous electrolyte secondary battery. It encompasses all things broadly.
  • a non-aqueous electrolyte secondary battery which is a preferred embodiment of the present invention, has a configuration including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode.
  • the positive electrode has a positive electrode current collector and a positive electrode active material layer in contact with the positive electrode current collector
  • the negative electrode has a negative electrode current collector and a negative electrode active material layer in contact with the negative electrode current collector.
  • at least one of the positive electrode active material layer and the negative electrode active material layer is formed using the electrode composition of the present invention.
  • the non-aqueous electrolyte secondary battery of the present invention has only one of the positive electrode active material layer and the negative electrode active material layer, and the electrode active material layer having this electrode active material layer uses the electrode composition of the present invention.
  • a non-aqueous electrolyte secondary battery having a formed structure is also included.
  • the non-aqueous electrolyte secondary battery of the present invention functions as a secondary battery by charging and discharging by filling a non-aqueous electrolyte between the positive electrode and the negative electrode.
  • FIG. 1 is a schematic cross-sectional view showing a laminate structure of a general non-aqueous electrolyte secondary battery 10 including working electrodes when operated as a battery.
  • the non-aqueous electrolyte secondary battery 10 has a laminated structure having, when viewed from the negative electrode side, a negative electrode current collector 1, a negative electrode active material layer 2, a separator 3, a positive electrode active material layer 4, and a positive electrode current collector 5 in this order. are doing.
  • a space between the negative electrode active material layer 2 and the positive electrode active material layer 4 is filled with a non-aqueous electrolyte (not shown) and separated by the separator 3 .
  • the separator 3 has pores, and functions as a positive/negative separator that insulates the positive/negative electrodes while permeating the electrolyte and ions through the pores under normal battery usage conditions.
  • a positive/negative separator that insulates the positive/negative electrodes while permeating the electrolyte and ions through the pores under normal battery usage conditions.
  • a light bulb is employed as the actuating portion 6, which is lit by discharge.
  • the negative electrode current collector 1 and the negative electrode active material layer 2 are collectively referred to as a negative electrode
  • the positive electrode active material layer 4 and the positive electrode current collector 5 are collectively referred to as a positive electrode.
  • the secondary battery of the present invention comprises at least one of a positive electrode active material layer and a negative electrode active material layer formed using the secondary battery binder composition or electrode composition of the present invention.
  • the electrolytic solution aqueous electrolytic solution, non-aqueous electrolytic solution
  • electrolytes such as solid electrolyte materials, and other members such as separators are not particularly limited. As these materials, members, and the like, those used in ordinary secondary batteries can be appropriately applied.
  • at least one of the positive electrode active material layer and the negative electrode active material layer is formed using the secondary battery binder composition or the electrode composition of the present invention.
  • conventional methods can be employed as appropriate.
  • JP 2016-201308, JP 2005-108835, JP 2012-185938 and WO 2020/067106 etc. can be referred to as appropriate.
  • a preferred form of the non-aqueous electrolyte will be described in more detail.
  • the electrolyte used for the non-aqueous electrolyte is preferably a salt of a metal ion belonging to Group 1 or Group 2 of the periodic table.
  • the metal ion salt to be used is appropriately selected depending on the intended use of the non-aqueous electrolyte. Examples include lithium salts, potassium salts, sodium salts, calcium salts, magnesium salts, etc. When used in secondary batteries and the like, lithium salts are preferred from the viewpoint of output.
  • a non-aqueous electrolyte is used as an electrolyte for a lithium ion secondary battery, a lithium salt may be selected as the metal ion salt.
  • the lithium salt is preferably a lithium salt that is commonly used in electrolytes for lithium ion secondary batteries, and examples thereof include the following lithium salts.
  • Inorganic lithium salts inorganic fluoride salts such as LiPF 6 , LiBF 4 , LiAsF 6 and LiSbF 6 , perhalogenates such as LiClO 4 , LiBrO 4 and LiIO 4 , inorganic chloride salts such as LiAlCl 4 etc
  • (L-2) Fluorine-containing organic lithium salts Perfluoroalkanesulfonates such as LiCF 3 SO 3 , LiN(CF 3 SO 2 ) 2 , LiN(CF 3 CF 2 SO 2 ) 2 , LiN(FSO 2 ) 2 , perfluoroalkanesulfonylimide salts such as LiN( CF3SO2 ) ( C4F9SO2 ) , perfluoroalkanesulfonylmethide salts such as LiC( CF3SO2 ) 3 , Li [ PF5 ( CF2 CF2CF3 ) ], Li[ PF4 ( CF2CF2CF3 ) 2 ] , Li [ PF3 (CF2CF2CF3 ) 3 ] , Li [ PF5 ( CF2CF2CF3 )], Li[PF 4 (CF 2 CF 2 CF 2 CF 3 ) 2 ], Li[PF 3 (CF 2 CF 2 CF 2 CF 2
  • Oxalatoborate salts lithium bis(oxalato)borate, lithium difluorooxalatoborate, etc.
  • LiPF6 , LiBF4 , LiAsF6, LiSbF6 , LiClO4 , Li( Rf1SO3 ) , LiN( Rf1SO2 ) 2 , LiN( FSO2 ) 2 , or LiN( Rf1 SO 2 )(R f2 SO 2 ) are preferred, LiPF 6 , LiBF 4 , LiN(R f1 SO 2 ) 2 , LiN(FSO 2 ) 2 or LiN(R f1 SO 2 )(R Lithium imide salts such as f2SO2 ) are more preferred.
  • each of R f1 and R f2 represents a perfluoroalkyl group, preferably having 1 to 6 carbon atoms.
  • the electrolyte used for a nonaqueous electrolyte may be used individually by 1 type, or may combine 2 or more types arbitrarily.
  • the salt concentration of the electrolyte in the non-aqueous electrolyte (preferably the ion of a metal belonging to Group 1 or Group 2 of the periodic table or a metal salt thereof) is appropriately selected depending on the purpose of use of the non-aqueous electrolyte, but generally is 10 to 50% by mass, preferably 15 to 30% by mass, of the total mass of the non-aqueous electrolyte.
  • the molar concentration is preferably 0.5-1.5M. When the concentration of ions is evaluated, it may be calculated by salt conversion with the suitably applied metal.
  • the non-aqueous electrolyte contains a non-aqueous solvent.
  • a non-aqueous solvent an aprotic organic solvent is preferable, and an aprotic organic solvent having 2 to 10 carbon atoms is more preferable.
  • examples of such non-aqueous solvents include chain or cyclic carbonate compounds, lactone compounds, chain or cyclic ether compounds, ester compounds, nitrile compounds, amide compounds, oxazolidinone compounds, nitro compounds, chain or cyclic sulfones or Examples include sulfoxide compounds and phosphate ester compounds.
  • a compound having an ether bond, a carbonyl bond, an ester bond or a carbonate bond is preferred. These compounds may have a substituent, and examples of the substituent which may have include a substituent selected from the above-described substituent group T.
  • Non-aqueous solvents include, for example, ethylene carbonate, fluoroethylene carbonate, vinylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, methylpropyl carbonate, ⁇ -butyrolactone, ⁇ -valerolactone, 1, 2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,3-dioxane, 1,4-dioxane, methyl acetate, ethyl acetate, propion Methyl acid, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethylacetate, ethyl trimethylacetate, acetonitrile, glutaronitrile, adiponitrile, me
  • At least one selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and ⁇ -butyrolactone is preferable, and a high viscosity (high dielectric constant) solvent such as ethylene carbonate or propylene carbonate (for example, , dielectric constant ⁇ 30) and a low-viscosity solvent such as dimethyl carbonate, ethylmethyl carbonate or diethyl carbonate (for example, viscosity ⁇ 1 mPa ⁇ s) is more preferable.
  • a high viscosity (high dielectric constant) solvent such as ethylene carbonate or propylene carbonate (for example, , dielectric constant ⁇ 30)
  • a low-viscosity solvent such as dimethyl carbonate, ethylmethyl carbonate or diethyl carbonate (for example, viscosity ⁇ 1 mPa ⁇ s) is more preferable.
  • the secondary battery of the present invention can be used, for example, in notebook computers, pen-input computers, mobile computers, e-book players, mobile phones, cordless phone slaves, pagers, handy terminals, mobile faxes, mobile copiers, mobile printers, headphone stereos, and videos. It can be installed in electronic equipment such as movies, liquid crystal televisions, handy cleaners, portable CDs, minidiscs, electric shavers, transceivers, electronic notebooks, calculators, portable tape recorders, radios, backup power supplies, memory cards, and the like.
  • Liquid prepared in a separate container (acrylamide (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) 75.0 g, distilled water 75.0 g, VA-057 (trade name, water-soluble azo polymerization initiator manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) 0.53 g was stirred at room temperature and mixed) was added dropwise to distilled water in a 1 L three-necked flask over 1 hour. After completion of dropping, stirring was continued at 75° C. for 3 hours. After cooling to room temperature, an aqueous solution of water-soluble polymer (X) (polyacrylamide (PAAm)) used for preparing binder compositions 1 and c1 to c3 was obtained. Solid concentration was 14.0% by mass, Mw was 347000, and Mw/Mn was 2.40.
  • Binder compositions 1 and c1 to c3 except that acrylamide and acrylic acid were used in place of acrylamide in the synthesis example of the water-soluble polymer (X) at an acrylamide/acrylic acid ratio of 97/3 (mass ratio).
  • An aqueous solution of the water-soluble polymer (X) used in the preparation of the binder composition 2 shown in Table 1 below was obtained in the same manner as in the preparation of the aqueous solution of the water-soluble polymer (X) used in the preparation of .
  • a binder composition 1 described in Table 1 below was prepared. Specifically, in a 60 mL ointment container (manufactured by Umano Kagaku), 7.50 g of an aqueous solution of water-soluble polymer (X) (PAAm) (solid content: 1.05 g), water-soluble polymer (Y) (carboxymethyl cellulose (CMC)) was added, and dispersed for 4 minutes at 2000 rpm using an Awatori Mixer (trade name, manufactured by THINKY).
  • PAAm water-soluble polymer
  • Y carboxymethyl cellulose
  • Binder composition 1 was obtained by dispersing at 2000 rpm for 2 minutes using a Tori Mixer.
  • Binder compositions 2 to 11 and c1 to c5 were prepared in the same manner as the binder composition 1, except that the composition shown in Table 1 below was used in the preparation of the binder composition 1.
  • a polymer sheet was formed on a peelable PET film (5 cm long, 0.5 cm wide, 0.1 mm film thickness) by applying each binder composition described in Table 1 below and drying the coating.
  • a test piece was obtained by peeling a polymer sheet (5 cm long, 0.5 cm wide, 0.030 to 0.150 mm film thickness) from the PET film.
  • a tensile tester (trade name: FGS-TV, manufactured by Nidec-Shimpo)
  • FGS-TV tensile tester
  • the breaking energy was calculated from the stress-strain curve obtained from the results of measuring the load against displacement. The obtained breaking energy was applied to the following evaluation ranks and evaluated. The results are shown in Table 1 below.
  • -Evaluation Rank- 4 1.5 MPa or more 3: 1.0 MPa or more and less than 1.5 MPa 2: 0.5 MPa or more and less than 1.0 MPa 1: less than 0.5 MPa
  • Mw, Mn and Mw/Mn are values obtained by measuring the copolymer before neutralization.
  • CMC Celogen WS-C (trade name), manufactured by Daiichi Kogyo Seiyaku Co., Ltd., carboxymethyl cellulose (degree of etherification 0.66) (The polymers listed in the column of water-soluble polymer (X) in Table 1, such as PAAm and AAm/AA, and CMC all have a solubility in water of 10 g/L-H 2 O or more at 20°C. there were.
  • SR-151 Nalstar SR-151 (trade name), styrene-butadiene rubber manufactured by Nippon A&L Co., Ltd.
  • SR-153 Nalstar SR-153 (trade name), styrene-butadiene rubber manufactured by Japan A&L Co., Ltd.
  • Particulate polymer Z1 International publication Particulate polymer Z1 consisting of a styrene-butadiene copolymer polymerized according to paragraph [0141] of 2015/186363 (All of the above SR-151, SR-153 and particulate polymer Z1 had a solubility in water of less than 10 g/L-H 2 O at 20°C.) Content (%): The ratio of each polymer (solid content) to the total of each polymer (solid content) contained in the binder composition is shown on a mass basis (“%” in Table 1 means “mass %”.).
  • Mw Weight average molecular weight of water-soluble polymer (X)
  • Mn Number average molecular weight of water-soluble polymer (X)
  • Mw/Mn Molecular weight distribution of water-soluble polymer (X) Tg of SR-151 is 2 points (- 27° C. and 15° C.) are observed (catalog values of Japan A&L Co., Ltd.).
  • Tables 2-A and 2-B are collectively referred to as Table 2.
  • a negative electrode composition 1 shown in Table 2 below was prepared.
  • This negative electrode composition is one embodiment of the binder composition of the present invention.
  • negative electrode composition 2 was prepared in the same manner as negative electrode composition 1, except that the composition shown in Table 2 below was used instead of the composition of negative electrode composition 1. ⁇ 11 and c1-c5 were prepared.
  • a negative electrode sheet 1 described in Table 2 below was produced. Specifically, the negative electrode composition 1 thus obtained was applied onto a copper foil having a thickness of 18 ⁇ m, a width of 90 mm and a length of 240 mm using an applicator, and dried at 80° C. for 1 hour. Thereafter, using a pressing machine, it was dried at 150° C. in vacuum for 6 hours after pressurization to obtain a negative electrode sheet 1 (50 to 80 mm wide, 150 to 210 mm long) having a thickness of the negative electrode active material layer of 25 ⁇ m. .
  • negative electrode sheets 2 to 11 and c1 to 2 were prepared in the same manner as in the production of negative electrode sheet 1, except that the negative electrode composition described in Table 2 below was used instead of negative electrode composition 1. c5 was produced.
  • Adhesive tape (10 mm wide, 50 mm long, product name: Nicetac Business Pack, double-sided tape, manufactured by Nichiban Co., Ltd.) is attached to each of the negative electrode active material layers of the three cut test pieces, and through this adhesive tape, Each test piece was attached to a glass plate. Placed with the glass plate facing downward, the average stress was measured for each test piece when the copper foil (current collector) was peeled off from the negative electrode active material layer at an angle of 90° and at a rate of 100 mm/min. .
  • a non-aqueous electrolyte secondary battery 1 (No. 1 battery in Table 2 below) was produced. Specifically, a disk with a diameter of 13.0 mm was cut out from the negative electrode sheet and used to form the negative electrode. Lithium foil (thickness 50 ⁇ m , 14.5 mm ⁇ ) and polypropylene separator (thickness 25 ⁇ m, 16.0 mm ⁇ ) are stacked in this order. soaked in. 200 ⁇ L of the electrolytic solution was further impregnated on the separator, and the negative electrode sheet was stacked so that the negative electrode active material layer surface was in contact with the separator. After that, the 2032 type coin case was crimped to prepare a non-aqueous electrolyte secondary battery 1 (a battery having a laminate consisting of Li foil-separator-negative electrode active material layer-copper foil).
  • non-aqueous Electrolyte secondary batteries 2 to 11 and c1 to c5 (batteries Nos. 2 to 11 and c1 to c5 in Table 2 below) were produced.
  • Cycle characteristics were evaluated by repeating 80 charge/discharge cycles, with one charge/discharge cycle as one charge/discharge cycle. Assuming that the discharge capacity at the first cycle after initialization (initial discharge capacity) is 100%, the discharge capacity retention rate at the 80th cycle (100 ⁇ “80th cycle discharge capacity” / “initial discharge capacity”) was calculated. , was applied to the following evaluation ranks, and the cycle characteristics were evaluated. The results are shown in Table 2 below. -Evaluation rank of discharge capacity retention rate- 6: 90% or more 5: 85% or more and less than 90% 4: 80% or more and less than 85% 3: 70% or more and less than 80% 2: 50% or more and less than 70% 1: less than 50%
  • SiOC carbon-coated silicon oxide (content ratio of carbon element: 1.3% by mass, average particle size: 5 ⁇ m, manufactured by Osaka Titanium Technologies Co., Ltd.)
  • Graphite MAG-D (trade name, manufactured by Showa Denko Materials)
  • AB Acetylene black (trade name: Denka Black, manufactured by Denka)
  • Water-soluble polymer (X) such as PAAm, AAm/AA (97/3), CMC, polymer particles such as SR-151: see ⁇ Notes in Table 1> Content (%): in the negative electrode composition
  • % in Table 2 means “% by mass”).
  • negative electrode composition No. 1 to 11 and c1 to c5 the content of SiOC described in the column of high-capacity active material is 17.8% by mass, the content of graphite described in the column of active material is 71.2% by mass, and the conductive aid is 6.00% by mass, and these descriptions are omitted in the above table.
  • Value of ratio of tensile modulus tensile modulus of water-soluble polymer (X)/tensile modulus of polymer particles. It is a value calculated based on the value of the tensile modulus described in Table 1.
  • Table 2 reveals the following.
  • No. The negative electrode composition c1 was prepared without using the water-soluble polymer (Y) and polymer particles. No. No. c1 produced using the negative electrode composition. The negative electrode sheet of c1 was inferior in adhesion.
  • No. The negative electrode composition of c2 was prepared without using polymer particles. No. No. c2 produced using the negative electrode composition. The negative electrode sheet of c2 had poor adhesion.
  • the negative electrode composition c3 was prepared without using the water-soluble polymer (Y). No. The negative electrode composition of c3 has low dispersibility, and No. c3 produced using this composition. The negative electrode sheet of c3 had insufficient adhesion. In addition, No. 1 produced using the above composition.
  • the c3 secondary battery was inferior in cycle characteristics.
  • the negative electrode compositions c4 and 5 were prepared using the water-soluble polymer (X) and polymer particles whose "ratio of tensile elastic moduli" did not meet the requirements of the present invention.
  • No. Nos. c4 and 5 prepared using the negative electrode compositions.
  • the secondary batteries of c4 and 5 were inferior in cycle characteristics.
  • the negative electrode sheets (Nos. 1 to 11) of the present invention produced using the negative electrode compositions (Nos. 1 to 11) of the present invention have excellent adhesion.
  • the secondary batteries (Nos. 1 to 11) of the present invention produced using the negative electrode compositions (Nos. 1 to 11) of the present invention have excellent cycle characteristics.
  • the pulverized silicon oxide was placed in a silicon nitride tray and then placed in a processing furnace capable of maintaining an atmosphere.
  • argon gas was introduced to replace the inside of the treatment furnace with argon
  • the temperature was raised at a temperature elevation rate of 300°C/hr while introducing a methane-argon mixed gas at 2 NL/min to reach a temperature of 600 to 1,100°C. and held for 3 to 10 hours to perform thermal CVD to obtain carbon-coated silicon oxide (SiOC).
  • SiOC carbon-coated silicon oxide
  • the temperature was started to drop, and after reaching room temperature, the powder was collected. Subsequently, the carbon-coated silicon oxide was doped with lithium by an oxidation-reduction method for modification.
  • the carbon-coated silicon oxide was immersed in a solution (solution A) in which lithium pieces and naphthalene were dissolved in tetrahydrofuran (hereinafter referred to as THF).
  • this solution A is obtained by dissolving naphthalene in a THF solvent at a concentration of 0.2 mol/L, and then adding 10% by mass of lithium pieces to the mixed solution of this THF solvent and naphthalene. It was made by adding Further, the temperature of the solution A when the carbon-coated silicon oxide was immersed was set to 20° C., and the immersion time was set to 20 hours. After that, the solid content was collected by filtration. Lithium was doped into the carbon-coated silicon oxide by the above treatment.
  • the obtained solid content was heat-treated at 600° C. for 24 hours in an argon atmosphere to stabilize the Li compound.
  • the carbon-coated silicon oxide was modified to obtain silicon oxide (LiSiOC) that was both lithium-doped and carbon-coated.
  • the carbon element content was 3% by mass, and the LiSiOC particles had an average particle diameter (volume-based median diameter D50) of 6.7 ⁇ m.
  • An argon atmosphere was used as the atmosphere during the production of the molten alloy and the gas atomization. Further, at the time of gas atomization, high-pressure (4 MPa) argon gas was sprayed onto the molten alloy falling like a rod in the atomization chamber. The obtained powder was sieved to a size of 25 ⁇ m or less and used as the Si alloy in the subsequent steps.
  • the silicon-based material doped with the metal element after the mechanical milling treatment was placed in a silicon nitride tray, and then placed in a treatment furnace capable of holding an atmosphere.
  • argon gas was introduced to replace the inside of the treatment furnace with argon, the temperature was raised at a temperature elevation rate of 300°C/hr while introducing a methane-argon mixed gas at 2 NL/min to reach a temperature of 600 to 1,100°C.
  • the carbon film is subjected to thermal CVD by holding for 3 to 10 hours, and a silicon-based material with both metal element doping and carbon coating (silicon oxide with both nickel doping and carbon coating (NiSiOC ) and both titanium-doped and carbon-coated silicon oxide (TiSiOC)).
  • a silicon-based material with both metal element doping and carbon coating silicon oxide with both nickel doping and carbon coating (NiSiOC ) and both titanium-doped and carbon-coated silicon oxide (TiSiOC)
  • the temperature was started to drop, and after reaching room temperature, the powder was recovered.
  • the carbon element content was 3% by mass, and the average particle diameter (volume-based median diameter D50) of the NiSiOC particles and the TiSiOC particles was both 7 ⁇ m.
  • NiSiO nickel-doped silicon oxide
  • TiSiO titanium-doped silicon oxide alloy
  • Composition total 100% by weight of Si alloy and SiO2 powder introduced in obtaining silicon-based material doped with metal elements (NiSiO or TiSiO) The ratio of each metal element in the Si alloy to the total of the alloy composition is 95% by mass.
  • Mixing ratio Indicates the ratio of each component (Si alloy or SiO2 powder) to the total of Si alloy and SiO2 powder introduced when obtaining a silicon-based material (NiSiO or TiSiO) doped with a metal element, and the unit is % by mass.
  • the high-capacity active materials in the negative electrode compositions 1 to 11 and c1 to c5 described in Table 2 above are carbon-coated silicon oxide (SiOC) (A (B) both nickel-doped and carbon-coated silicon oxide (NiSiOC); or (C) both titanium-doped and carbon-coated.
  • SiOC carbon-coated silicon oxide
  • NiSiOC nickel-doped and carbon-coated silicon oxide
  • C both titanium-doped and carbon-coated.
  • Negative electrode compositions 1-A to 11-A and c1-A to c5-A, c1-A to c5-A, and Negative electrode compositions 1-B to 11-B and c1-B to c5-B, and negative electrode compositions 1-C to 11-C and c1-C to c5-C were prepared, respectively.
  • Adhesive tape (10 mm wide, 50 mm long, product name: Nicetac Business Pack, double-sided tape, manufactured by Nichiban Co., Ltd.) is attached to each of the negative electrode active material layers of the three cut test pieces, and through this adhesive tape, Each test piece was attached to a glass plate. Placed with the glass plate facing downward, the average stress was measured for each test piece when the copper foil (current collector) was peeled off from the negative electrode active material layer at an angle of 90° and at a rate of 100 mm/min. .
  • a value (unit: N) obtained by dividing the sum of each average stress obtained by 3 was applied to the following evaluation rank and evaluated. The results are shown in Table 3 below.
  • Table 3-A Lithium-doped and carbon-coated carbon-coated silicon oxide (SiOC), which is a high-capacity active material in the negative electrode composition, negative electrode sheet, and batteries 1 to 11 and c1 to c5 described in Table 2 above. Evaluations of negative electrode compositions, negative electrode sheets, and batteries 1-A to 11-A and c1-A to c5-A, which are changed to silicon oxide (LiSiOC) to which both of are applied, are described.
  • SiOC silicon oxide
  • Table 3-B Ni-doped and carbon-coated carbon-coated silicon oxide (SiOC), which is a high-capacity active material in the negative electrode composition, negative electrode sheet, and batteries 1 to 11 and c1 to c5 described in Table 2 above. Evaluations of negative electrode compositions, negative electrode sheets, and batteries 1-B to 11-B and c1-B to c5-B, which were changed to silicon oxide (NiSiOC) subjected to both of the above, are described.
  • Table 3-C Carbon-coated silicon oxide (SiOC), which is a high-capacity active material in the negative electrode composition, negative electrode sheet, and batteries 1 to 11 and c1 to c5 described in Table 2 above, is titanium-doped and carbon-coated. Evaluations of negative electrode compositions, negative electrode sheets, and batteries 1-C to 11-C and c1-C to c5-C, which are changed to silicon oxide (TiSiOC) to which both are applied, are described.
  • Table 3 shows the following.
  • high-capacity active materials instead of carbon-coated silicon oxide (SiOC), both lithium-doped and carbon-coated silicon oxide (LiSiOC), nickel-doped and carbon-coated silicon oxide ( NiSiOC) or both titanium-doped and carbon-coated silicon oxide (TiSiOC).
  • SiOC silicon oxide
  • TiSiOC titanium-doped and carbon-coated silicon oxide
  • the adhesion of the negative electrode sheet prepared using each negative electrode composition and the cycle characteristics of the secondary battery prepared using each negative electrode composition were also evaluated when the high-capacity active material in Table 2 was carbon-coated. It was found that the adhesion and cycle characteristics of the corresponding negative electrode sheet, which has the same composition except that it is silicon oxide (SiOC), show similar tendencies to those of the secondary battery.

Abstract

The present invention provides: a binder composition for secondary batteries, the binder composition containing a water-soluble polymer (X), a water-soluble polymer (Y) and polymer particles, wherein the water-soluble polymer (X) comprises a constituent having a specific structure, and the ratio of the tensile elastic modulus of the water-soluble polymer (X) to the tensile elastic modulus of the polymer particles is more than 10; an electrode sheet; a secondary battery; a method for producing the electrode sheet; and a method for producing the secondary battery.

Description

二次電池用バインダー組成物、電極シート及び二次電池、並びに、これら電極シート及び二次電池の製造方法Binder composition for secondary battery, electrode sheet and secondary battery, and method for producing electrode sheet and secondary battery
　本発明は、二次電池用バインダー組成物、電極シート及び二次電池、並びに、これら電極シート及び二次電池の製造方法に関する。 The present invention relates to a binder composition for secondary batteries, an electrode sheet, a secondary battery, and a method for manufacturing these electrode sheets and secondary batteries.
　リチウムイオン二次電池に代表される二次電池は、パソコン、ビデオカメラ、携帯電話等のポータブル電子機器の動力源として用いられている。最近では、二酸化炭素排出量削減という地球規模の環境課題を背景に、自動車等の輸送機器の動力電源として、また、夜間電力、自然エネルギー発電による電力等の蓄電用途としても普及してきている。 　Secondary batteries, typified by lithium-ion secondary batteries, are used as power sources for portable electronic devices such as personal computers, video cameras, and mobile phones. Recently, against the background of the global environmental issue of reducing carbon dioxide emissions, it is becoming popular as a power source for transportation equipment such as automobiles, and as a power storage application such as nighttime power and power generated by natural energy generation.
　リチウムイオン二次電池の電極（正極及び負極）は一般的には電極活物質層（正極活物質層及び負極活物質層）を有し、この電極活物質層は、充放電時にリチウムイオンを吸蔵ないし放出可能な電極活物質粒子を含み、また、必要により導電助剤等を含む。電極活物質、導電助剤等はいわゆる固体粒子であり、リチウムイオン二次電池の充放電（リチウムイオンの吸蔵放出）に伴う電極活物質粒子の膨張収縮により、固体粒子間の導通状態は損なわれやすい。導通状態が損なわれれば電池の内部抵抗が増大して電池容量が低下する。リチウムイオン二次電池のサイクル特性を向上させる（サイクル寿命を長期化する）には、充放電を繰り返しても固体粒子間の密着状態を維持できることが重要であり、電極活物質層は通常、バインダーを含む。
　例えば、特許文献１には、粒子状重合体及び水溶性重合体を含むリチウムイオン二次電池電極用バインダー組成物が記載されている。特許文献１には、この組成物を構成する水溶性重合体が、エチレン性不飽和カルボン酸単量体単位と、（メタ）アクリルアミド、Ｎ－［２－（ジメチルアミノ）エチル］（メタ）アクリルアミド、Ｎ－［３－（ジメチルアミノ）プロピル］（メタ）アクリルアミドから選ばれる一種以上のカルボン酸アミド単量体単位と、上記カルボン酸アミド単量体単位以外の架橋性単量体単位とを、それぞれ特定の割合で含むこと；この組成物と、電極活物質と、カルボキシメチルセルロース塩とを組み合わせて、リチウムイオン二次電池の電極形成に適用することによって、得られるリチウムイオン二次電池中においてガスの発生を抑制し、リチウムイオン二次電池のサイクル特性が向上することが記載されている。 The electrodes (positive electrode and negative electrode) of a lithium ion secondary battery generally have an electrode active material layer (positive electrode active material layer and negative electrode active material layer), and this electrode active material layer absorbs lithium ions during charging and discharging. It also contains releasable electrode active material particles and, if necessary, conductive aids and the like. Electrode active materials, conductive aids, etc. are so-called solid particles, and due to expansion and contraction of the electrode active material particles accompanying charging and discharging (occlusion and release of lithium ions) of the lithium ion secondary battery, the conductive state between the solid particles is impaired. Cheap. If the conduction state is lost, the internal resistance of the battery increases and the battery capacity decreases. In order to improve the cycle characteristics (extend the cycle life) of lithium-ion secondary batteries, it is important to be able to maintain the adhesion state between solid particles even after repeated charging and discharging. including.
For example, Patent Document 1 describes a binder composition for lithium ion secondary battery electrodes containing a particulate polymer and a water-soluble polymer. Patent Document 1 discloses that the water-soluble polymer constituting this composition contains ethylenically unsaturated carboxylic acid monomer units, (meth)acrylamide, N-[2-(dimethylamino)ethyl](meth)acrylamide , N-[3-(dimethylamino)propyl](meth)acrylamide, and a crosslinkable monomer unit other than the carboxylic acid amide monomer unit, containing each in a specific proportion; gas in a lithium ion secondary battery obtained by combining this composition, an electrode active material, and a carboxymethyl cellulose salt and applying it to form an electrode of a lithium ion secondary battery It is described that the generation of is suppressed and the cycle characteristics of the lithium ion secondary battery are improved.
特許第６３６１６５５号Patent No. 6361655
　近年、二次電池の用途の拡大に伴い、二次電池には高エネルギー密度化及びサイクル特性の更なる向上が求められている。リチウムイオン二次電池の更なる高容量化を実現するために、負極活物質としてケイ素系活物質を用いる検討が盛んに行われている。負極にケイ素系活物質を用いると高エネルギー密度化が可能となる。しかし、ケイ素系活物質は充電時にリチウムイオンを多量に吸蔵して大きく膨張するため、その分、放電時におけるケイ素系活物質の収縮幅も大きくなる。したがって、負極活物質としてケイ素系活物質を用いたリチウムイオン二次電池は、充放電時の負極活物質の体積変化が大きく、固体粒子（電極活物質、導電助剤等）間の導通状態（密着状態）が損なわれやすいため、充放電の繰り返しにより電池性能が低下しやすい。つまり、サイクル特性の向上には制約がある。また、負極活物質としてケイ素系活物質を用いたリチウムイオン二次電池は、充放電時の負極活物質の体積変化により負極活物質層－集電体間の剥離も生じやすいため、長期間の使用に耐えられない。
　本発明者らは、かかるケイ素系活物質を負極活物質として用いた二次電池において、上記特許文献１に記載されたバインダーなどの従来の電極用バインダーがサイクル特性に与える影響について検討した。その結果、従来の電極用バインダーでは、充放電に伴うケイ素系活物質のダイナミックな体積変化に十分に対応することができず、電極シートの密着性及び二次電池のサイクル特性を両立して目的の高いレベルへと導くことが難しいことが明らかとなってきた。 In recent years, secondary batteries have been required to have higher energy densities and further improvements in cycle characteristics as the applications of secondary batteries have expanded. In order to further increase the capacity of lithium-ion secondary batteries, extensive studies have been conducted on the use of silicon-based active materials as negative electrode active materials. High energy density can be achieved by using a silicon-based active material for the negative electrode. However, since the silicon-based active material absorbs a large amount of lithium ions during charging and expands greatly, the shrinkage width of the silicon-based active material during discharging also increases accordingly. Therefore, in a lithium-ion secondary battery using a silicon-based active material as a negative electrode active material, the volume change of the negative electrode active material during charging and discharging is large, and the conduction state ( contact state) is likely to be impaired, so battery performance is likely to deteriorate due to repeated charging and discharging. In other words, there are restrictions on improving cycle characteristics. In addition, lithium-ion secondary batteries that use a silicon-based active material as the negative electrode active material are prone to peeling between the negative electrode active material layer and the current collector due to changes in the volume of the negative electrode active material during charging and discharging, so they cannot be used for a long period of time. cannot withstand use.
The inventors of the present invention have investigated the effects of conventional electrode binders, such as the binder described in Patent Document 1, on the cycle characteristics of a secondary battery using such a silicon-based active material as a negative electrode active material. As a result, conventional binders for electrodes cannot sufficiently respond to the dynamic volume changes of silicon-based active materials that accompany charging and discharging. It has become clear that it is difficult to lead to high levels of
　本発明は、充放電時の体積変化の大きな電極活物質を用いた場合でも、得られる電極シートの密着性（負極活物質層－集電体間の密着性）を十分に高め、かつ、得られる二次電池のサイクル特性を十分に高める（サイクル寿命を十分に長期化する）ことができる二次電池用バインダー組成物を提供することを課題とする。
　更に、本発明は、上記二次電池用バインダー組成物を用いた電極シート及び二次電池を提供することを課題とする。更に、本発明は、上記電極シート及び二次電池の製造方法を提供することを課題とする。 The present invention sufficiently enhances the adhesion of the obtained electrode sheet (adhesion between the negative electrode active material layer and the current collector) even when using an electrode active material that undergoes a large volume change during charging and discharging, and obtains It is an object of the present invention to provide a secondary battery binder composition capable of sufficiently improving the cycle characteristics of a secondary battery (sufficiently lengthening the cycle life) of a secondary battery.
A further object of the present invention is to provide an electrode sheet and a secondary battery using the binder composition for a secondary battery. A further object of the present invention is to provide a method for manufacturing the electrode sheet and the secondary battery.
　本発明者らは上記課題に鑑み、バインダーを構成するポリマーの化学構造、バインダーの物性ないし形状について種々の検討を重ねた。その結果、重合体粒子と、特定の構造を有する水溶性高分子と、この水溶性高分子とは構造の異なる水溶性高分子とを組み合わせてなり、上記「重合体粒子」の引張弾性率に対する上記「特定の構造を有する水溶性高分子」の引張弾性率の比の値が特定の値を超えるバインダー組成物が、二次電池の層内又は層間の優れた結着性に効果的に寄与して、電極シートの密着性を高め、かつ、二次電池のサイクル寿命を十分に長期化できることを見出した。本発明はこれらの知見に基づき更に検討を重ね、完成されるに至ったものである。 In view of the above problems, the present inventors have made various studies on the chemical structure of the polymer that constitutes the binder and the physical properties and shape of the binder. As a result, a polymer particle, a water-soluble polymer having a specific structure, and a water-soluble polymer having a different structure from the water-soluble polymer are combined, and the tensile modulus of the "polymer particle" The binder composition in which the ratio of the tensile elastic moduli of the "water-soluble polymer having a specific structure" exceeds a specific value effectively contributes to excellent adhesion within or between the layers of the secondary battery. As a result, the inventors have found that the adhesion of the electrode sheet can be enhanced and the cycle life of the secondary battery can be sufficiently prolonged. The present invention has been completed through further studies based on these findings.
　すなわち、本発明の上記課題は以下の手段により解決された。
＜１＞
　水溶性高分子（Ｘ）、水溶性高分子（Ｙ）及び重合体粒子を含み、
　上記水溶性高分子（Ｘ）は、下記一般式（Ｂ－１）で表される構成成分及び／又は下記一般式（Ｂ－２）で表される構成成分を含む重合体であり、上記重合体粒子の引張弾性率に対する上記水溶性高分子（Ｘ）の引張弾性率の比の値（「上記水溶性高分子（Ｘ）の引張弾性率」／「上記重合体粒子の引張弾性率」）が１０を超える、二次電池用バインダー組成物。
Figure JPOXMLDOC01-appb-C000002
 　一般式（Ｂ－１）中、Ｒ１１～Ｒ１３は水素原子、シアノ基又は炭素数１～６のアルキル基を示し、Ｒ１４は水素原子、ヒドロキシ基、炭素数１～６のアルコキシ基、シアノ基、フェニル基、カルボキシ基、スルホ基、リン酸基又はホスホン酸基を示し、Ｌ１１は単結合、炭素数１～１６のアルキレン基、炭素数６～１２のアリーレン基、酸素原子、硫黄原子、カルボニル基若しくはイミノ基、又はこれらを組み合わせた連結基を示す。＊は上記水溶性高分子（Ｘ）の主鎖中に組み込まれるための結合部位を示す。
　一般式（Ｂ－２）中、Ｒ２１～Ｒ２３は水素原子、シアノ基又は炭素数１～６のアルキル基を示し、Ｒ２４は水素原子、アシル基、ヒドロキシ基、フェニル基又はカルボキシ基を示し、Ｌ２１は単結合、炭素数１～１６のアルキレン基、炭素数６～１２のアリーレン基、酸素原子、硫黄原子、カルボニル基若しくはイミノ基、又はこれらを組み合わせた連結基を示す。＊は上記水溶性高分子（Ｘ）の主鎖中に組み込まれるための結合部位を示す。
＜２＞
　上記水溶性高分子（Ｘ）が上記一般式（Ｂ－２）で表される構成成分を含む重合体である、＜１＞に記載の二次電池用バインダー組成物。
＜３＞
　上記水溶性高分子（Ｘ）中、上記一般式（Ｂ－２）で表される構成成分の含有量が８０質量％を超える、＜２＞に記載の二次電池用バインダー組成物。
＜４＞
　上記一般式（Ｂ－２）で表される構成成分がアクリルアミド成分を含む、＜２＞又は＜３＞に記載の二次電池用バインダー組成物。
＜５＞
　上記水溶性高分子（Ｘ）が、アクリロニトリル成分、Ｎ－ビニル－２－ピロリドン成分及びスチレン成分の少なくとも１種を、更に含む重合体である、＜１＞～＜４＞のいずれか１つに記載の二次電池用バインダー組成物。
＜６＞
　上記水溶性高分子（Ｙ）が多糖類である、＜１＞～＜５＞のいずれか１つに記載の二次電池用バインダー組成物。
＜７＞
　上記水溶性高分子（Ｙ）が、カルボキシメチルセルロース、セルロースナノファイバー、ヒドロキシエチルセルロース、ヒドロキシプロピルセルロース及びキサンタンガムの少なくとも１種を含む、＜１＞～＜６＞のいずれか１つに記載の二次電池用バインダー組成物。
＜８＞
　上記水溶性高分子（Ｘ）の重量平均分子量が１０００００～９０００００である、＜１＞～＜７＞のいずれか１つに記載の二次電池用バインダー組成物。
＜９＞
　上記水溶性高分子（Ｘ）の分子量分布（Ｍｗ／Ｍｎ）が５．０以下である、＜１＞～＜８＞のいずれか１つに記載の二次電池用バインダー組成物。
＜１０＞
　上記水溶性高分子（Ｘ）の引張弾性率が４０００ＭＰａ以上である、＜１＞～＜９＞のいずれか１つに記載の二次電池用バインダー組成物。
＜１１＞
　上記重合体粒子を構成する重合体が、共役ジエン成分、エチレン性不飽和カルボン酸成分、シアノ基含有エチレン性モノマー成分及び芳香族ビニルモノマー成分の少なくとも１種を含む重合体である、＜１＞～＜１０＞のいずれか１つに記載の二次電池用バインダー組成物。
＜１２＞
　上記重合体粒子のガラス転移温度が－５０～１５０℃である、＜１＞～＜１１＞のいずれか１つに記載の二次電池用バインダー組成物。
＜１３＞
　更に水を含む、＜１＞～＜１２＞のいずれか１つに記載の二次電池用バインダー組成物。
＜１４＞
　更に周期律表第１族又は第２族に属する金属のイオンの挿入放出が可能な活物質を含む、＜１＞～＜１３＞のいずれか１つに記載の二次電池用バインダー組成物。
＜１５＞
　上記活物質がケイ素系活物質を含む、＜１４＞に記載の二次電池用バインダー組成物。
＜１６＞
　＜１４＞又は＜１５＞に記載の二次電池用バインダー組成物を用いて形成した層を有する電極シート。
＜１７＞
　正極活物質層及び負極活物質層の少なくとも１つの層が、＜１４＞又は＜１５＞に記載の二次電池用バインダー組成物を用いて形成された層である、二次電池。
＜１８＞
　＜１４＞又は＜１５＞に記載の二次電池用バインダー組成物を用いて電極活物質層を形成することを含む、電極シートの製造方法。
＜１９＞
　＜１８＞に記載の製造方法により得られた電極シートを二次電池の電極として組み込むことを含む、二次電池の製造方法。 That is, the above problems of the present invention have been solved by the following means.
<1>
Water-soluble polymer (X), water-soluble polymer (Y) and polymer particles,
The water-soluble polymer (X) is a polymer containing a component represented by the following general formula (B-1) and/or a component represented by the following general formula (B-2). Ratio of the tensile elastic modulus of the water-soluble polymer (X) to the tensile elastic modulus of the coalesced particles (“tensile elastic modulus of the water-soluble polymer (X)”/“tensile elastic modulus of the polymer particles”) is greater than 10, a binder composition for secondary batteries.
Figure JPOXMLDOC01-appb-C000002
 In general formula (B-1), R 11 to R 13 represent a hydrogen atom, a cyano group or an alkyl group having 1 to 6 carbon atoms, R 14 represents a hydrogen atom, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, cyano group, phenyl group, carboxy group, sulfo group, phosphoric acid group or phosphonic acid group, L 11 is a single bond, an alkylene group having 1 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom, sulfur An atom, a carbonyl group, an imino group, or a combination of these linking groups. * indicates a binding site for incorporation into the main chain of the water-soluble polymer (X).
In general formula (B-2), R 21 to R 23 represent a hydrogen atom, a cyano group or an alkyl group having 1 to 6 carbon atoms, and R 24 represents a hydrogen atom, an acyl group, a hydroxy group, a phenyl group or a carboxy group. L 21 represents a single bond, an alkylene group having 1 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom, a sulfur atom, a carbonyl group, an imino group, or a linking group combining these. * indicates a binding site for incorporation into the main chain of the water-soluble polymer (X).
<2>
The binder composition for a secondary battery according to <1>, wherein the water-soluble polymer (X) is a polymer containing a component represented by the general formula (B-2).
<3>
The binder composition for a secondary battery according to <2>, wherein the water-soluble polymer (X) contains more than 80% by mass of the component represented by the general formula (B-2).
<4>
The binder composition for secondary batteries according to <2> or <3>, wherein the component represented by the general formula (B-2) contains an acrylamide component.
<5>
any one of <1> to <4>, wherein the water-soluble polymer (X) is a polymer further containing at least one of an acrylonitrile component, an N-vinyl-2-pyrrolidone component and a styrene component; The binder composition for secondary batteries described.
<6>
The binder composition for secondary batteries according to any one of <1> to <5>, wherein the water-soluble polymer (Y) is a polysaccharide.
<7>
The secondary battery according to any one of <1> to <6>, wherein the water-soluble polymer (Y) contains at least one of carboxymethylcellulose, cellulose nanofiber, hydroxyethylcellulose, hydroxypropylcellulose and xanthan gum. binder composition for
<8>
The binder composition for a secondary battery according to any one of <1> to <7>, wherein the water-soluble polymer (X) has a weight average molecular weight of 100,000 to 900,000.
<9>
The binder composition for a secondary battery according to any one of <1> to <8>, wherein the water-soluble polymer (X) has a molecular weight distribution (Mw/Mn) of 5.0 or less.
<10>
The binder composition for a secondary battery according to any one of <1> to <9>, wherein the water-soluble polymer (X) has a tensile modulus of 4000 MPa or more.
<11>
The polymer constituting the polymer particles is a polymer containing at least one of a conjugated diene component, an ethylenically unsaturated carboxylic acid component, a cyano group-containing ethylenic monomer component and an aromatic vinyl monomer component <1> The binder composition for secondary batteries according to any one of <10>.
<12>
The binder composition for a secondary battery according to any one of <1> to <11>, wherein the polymer particles have a glass transition temperature of -50 to 150°C.
<13>
The binder composition for secondary batteries according to any one of <1> to <12>, further comprising water.
<14>
The binder composition for a secondary battery according to any one of <1> to <13>, further comprising an active material capable of inserting and releasing ions of a metal belonging to Group 1 or Group 2 of the periodic table.
<15>
The binder composition for secondary batteries according to <14>, wherein the active material contains a silicon-based active material.
<16>
An electrode sheet having a layer formed using the binder composition for a secondary battery according to <14> or <15>.
<17>
A secondary battery, wherein at least one of the positive electrode active material layer and the negative electrode active material layer is a layer formed using the secondary battery binder composition according to <14> or <15>.
<18>
A method for producing an electrode sheet, comprising forming an electrode active material layer using the binder composition for a secondary battery according to <14> or <15>.
<19>
A method for producing a secondary battery, comprising incorporating the electrode sheet obtained by the production method according to <18> as an electrode of the secondary battery.
　本発明において、「水溶性高分子」とは、２０℃において水に対する溶解度が１０ｇ／Ｌ－Ｈ２Ｏ以上であるポリマー、すなわち、２０℃において水１リットルに対して１０ｇ以上溶解するポリマーを意味する。「水溶性高分子」の溶解度は１００ｇ／Ｌ－Ｈ２Ｏ以上であることが好ましい。
　本発明において、「～」を用いて表される数値範囲は、「～」の前後に記載される数値を下限値及び上限値として含む範囲を意味する。
　本発明において化合物、構成成分又は置換基の表示については、本発明の効果を奏する範囲で、構造の一部を変化させたものを含む意味である。更に、本発明において置換又は無置換を明記していない化合物又は構成成分については、本発明の効果を奏する範囲で、任意の置換基を有していてもよい意味である。このことは、置換基（例えば、「アルキル基」、「メチル基」、「メチル」等のように表現される基）及び連結基（例えば、「アルキレン基」、「メチレン基」、「メチレン」等のように表現される基）についても同様である。このような任意の置換基のうち、本発明において好ましい置換基は、後記する置換基群Ｔから選択される置換基である。
　本発明において、特定の符号又は式で示された置換基若しくは連結基等（以下、置換基等という）が複数あるとき、又は複数の置換基等を同時に規定するときには、特段の断りがない限り、それぞれの置換基等は互いに同一でも異なっていてもよい。このことは、ポリマーの構成成分についても同様である。
　本発明において、各成分は１種含有されていてもよく、２種以上含有されていてもよい。
　本発明において、（メタ）アクリルとは、アクリル及びメタクリルの一方又は両方を意味する。（メタ）アクリレートについても同様である。
　本発明において「二次電池」とは、充放電により電解質を介して正負極間をイオンが通過し、正負極においてエネルギーを貯蔵、放出するデバイス全般を意味する。すなわち、本発明において二次電池という場合、電池とキャパシタ（例えば、リチウムイオンキャパシタ）の両方を包含する意味である。エネルギー貯蔵量の観点から、本発明の二次電池は電池用途に用いること（キャパシタでないこと）が好ましい。
　二次電池は、用いる電解質に応じて水系二次電池と非水系二次電池とに大別でき、本発明においては、非水系二次電池が好ましい。本発明において「水系二次電池」とは、電解質として水系電解液を用いた二次電池を意味する。本発明において「非水系二次電池」とは、非水電解液二次電池と全固体二次電池とを含む意味である。本発明において「非水電解液二次電池」とは、電解質として非水電解液を用いた二次電池を意味する。本発明において「非水電解液」とは、水を実質的に含まない電解液を意味する。水を実質的に含まない電解液とは、「非水電解液」が本発明の効果を妨げない範囲で微量の水を含んでいてもよいことを意味する。本発明において「非水電解液」は、水の濃度が２００ｐｐｍ（質量基準）以下であり、１００ｐｐｍ以下が好ましく、２０ｐｐｍ以下がより好ましい。なお、非水電解液を完全に無水とすることは現実的に困難であり、通常は水が１ｐｐｍ以上含まれる。本発明において「全固体二次電池」とは、電解質として液を用いず、無機固体電解質、固体状ポリマー電解質等の固体電解質を用いた二次電池を意味する。
　本発明において、ある基の炭素数を規定する場合、この炭素数は、本発明ないし本明細書において特段の断りのない限りは、基そのものの炭素数を意味する。つまり、この基が更に置換基を有する形態である場合、この置換基の炭素数は含まずに数えた場合の炭素数を意味する。
　本発明において、含有量又は含有割合を記載する場合に使用する「固形分」とは、後述する水及び液媒体以外の成分を意味する。 In the present invention, the term "water-soluble polymer" means a polymer that has a solubility in water of 10 g/L-H 2 O or more at 20°C, that is, a polymer that dissolves in 1 liter of water at 20°C in an amount of 10 g or more. do. The solubility of the "water-soluble polymer" is preferably 100 g/L-H 2 O or more.
In the present invention, a numerical range represented by "to" means a range including the numerical values before and after "to" as lower and upper limits.
In the present invention, the representation of a compound, a constituent component, or a substituent means including those in which a part of the structure is changed within the range in which the effects of the present invention are exhibited. Furthermore, in the present invention, compounds or constituents for which substitution or non-substitution is not specified may have any substituent within the scope of the effects of the present invention. This includes substituents (e.g., groups expressed as "alkyl group", "methyl group", "methyl", etc.) and linking groups (e.g., "alkylene group", "methylene group", "methylene" The same applies to groups expressed as Among such optional substituents, preferred substituents in the present invention are substituents selected from the substituent group T described later.
In the present invention, when there are multiple substituents or connecting groups (hereinafter referred to as substituents, etc.) indicated by specific symbols or formulas, or when multiple substituents, etc. are defined at the same time, unless otherwise specified , the respective substituents and the like may be the same or different. This also applies to the constituent components of the polymer.
In the present invention, one type of each component may be contained, or two or more types may be contained.
In the present invention, (meth)acryl means one or both of acryl and methacryl. The same is true for (meth)acrylates.
In the present invention, the term "secondary battery" refers to all devices in which ions pass between the positive and negative electrodes via an electrolyte due to charging and discharging, and energy is stored and released at the positive and negative electrodes. In other words, the term "secondary battery" in the present invention includes both batteries and capacitors (for example, lithium ion capacitors). From the viewpoint of energy storage capacity, the secondary battery of the present invention is preferably used for battery applications (not a capacitor).
Secondary batteries can be broadly classified into aqueous secondary batteries and non-aqueous secondary batteries according to the electrolyte used, and non-aqueous secondary batteries are preferred in the present invention. In the present invention, the "aqueous secondary battery" means a secondary battery using an aqueous electrolytic solution as an electrolyte. In the present invention, the term "non-aqueous secondary battery" is meant to include non-aqueous electrolyte secondary batteries and all-solid secondary batteries. In the present invention, the "non-aqueous electrolyte secondary battery" means a secondary battery using a non-aqueous electrolyte as an electrolyte. In the present invention, "non-aqueous electrolyte" means an electrolyte that does not substantially contain water. An electrolytic solution that does not substantially contain water means that the "non-aqueous electrolytic solution" may contain a small amount of water within a range that does not impair the effects of the present invention. In the present invention, the "non-aqueous electrolyte" has a water concentration of 200 ppm (by mass) or less, preferably 100 ppm or less, more preferably 20 ppm or less. It is practically difficult to make the non-aqueous electrolyte completely anhydrous, and usually contains 1 ppm or more of water. In the present invention, the term "all-solid secondary battery" means a secondary battery using a solid electrolyte such as an inorganic solid electrolyte or a solid polymer electrolyte without using a liquid as the electrolyte.
In the present invention, when the carbon number of a certain group is defined, this carbon number means the carbon number of the group itself unless otherwise specified in the present invention or this specification. In other words, when this group is in the form of further having a substituent, it means the number of carbon atoms counted without including the number of carbon atoms of this substituent.
In the present invention, the "solid content" used when describing the content or content ratio means components other than water and the liquid medium, which will be described later.
　本発明の二次電池用バインダー組成物及び電極シートは、充放電時の体積変化の大きな電極活物質を用いた場合でも、得られる二次電池のサイクル寿命を十分に長期化することができる。また、本発明の電極シートは、密着性に優れる。
　本発明の二次電池は、充放電時の体積変化の大きな電極活物質を用いた場合にも、十分に長いサイクル寿命を実現できる。
　本発明の電極シートの製造方法によれば、本発明の上記電極シートを得ることができる。また、本発明の二次電池の製造方法によれば、本発明の上記二次電池を得ることができる。 The secondary battery binder composition and the electrode sheet of the present invention can sufficiently prolong the cycle life of the resulting secondary battery even when an electrode active material that undergoes a large volume change during charging and discharging is used. Moreover, the electrode sheet of the present invention has excellent adhesion.
The secondary battery of the present invention can achieve a sufficiently long cycle life even when using an electrode active material that undergoes a large volume change during charging and discharging.
According to the method for producing an electrode sheet of the present invention, the electrode sheet of the present invention can be obtained. Further, according to the method for manufacturing a secondary battery of the present invention, the secondary battery of the present invention can be obtained.
図１は、本発明に係る二次電池の一実施形態について、基本的な積層構成を模式化して示す縦断面図である。FIG. 1 is a vertical cross-sectional view schematically showing the basic lamination structure of one embodiment of the secondary battery according to the present invention.
［二次電池用バインダー組成物］
　本発明の二次電池用バインダー組成物（以降、「本発明のバインダー組成物」とも称す。）は、水溶性高分子（Ｘ）と、水溶性高分子（Ｙ）と、重合体粒子とを含有する。本発明のバインダー組成物は、好ましくは非水系二次電池、より好ましくは非水電解液二次電池を構成する部材ないし構成層の形成材料として好適である。本発明のバインダー組成物は、液媒体として、好ましくは水を含有する。典型的には、本発明のバインダー組成物は、二次電池の電極における電極活物質層の形成に好適に用いることができる。例えば、本発明のバインダー組成物に電極活物質（正極活物質又は負極活物質、これらを合わせて、単に「活物質」とも称す。）を含有させて非水系二次電池の電極（正極又は負極）活物質層の形成に用いることができる。 [Binder composition for secondary battery]
The secondary battery binder composition of the present invention (hereinafter also referred to as "the binder composition of the present invention") comprises a water-soluble polymer (X), a water-soluble polymer (Y), and polymer particles. contains. The binder composition of the present invention is suitable as a material for forming members or constituent layers that constitute a non-aqueous secondary battery, more preferably a non-aqueous electrolyte secondary battery. The binder composition of the invention preferably contains water as the liquid medium. Typically, the binder composition of the present invention can be suitably used for forming electrode active material layers in electrodes of secondary batteries. For example, an electrode active material (positive electrode active material or negative electrode active material, collectively referred to as an “active material”) is added to the binder composition of the present invention to form an electrode (positive electrode or negative electrode) of a non-aqueous secondary battery. ) can be used to form an active material layer.
　本発明のバインダー組成物が含有する水溶性高分子（Ｘ）及び重合体粒子は、例えば、本発明のバインダー組成物と固体粒子（電極活物質、導電助剤等）とを混合して形成した層中において、主として、これらの固体粒子同士を結着させる結着剤（バインダー）として機能すると考えられる。また、集電体と固体粒子とを結着させる結着剤としても機能しうる。水溶性高分子（Ｘ）及び重合体粒子の固体粒子及び集電体に対する吸着は、物理的吸着だけでなく、化学的吸着（化学結合の形成による吸着、電子の授受による吸着等）も含む。
　一方、本発明のバインダー組成物が含有する水溶性高分子（Ｙ）は、主として、本発明のバインダー組成物中で増粘剤（分散剤）として機能するものと考えられる。 The water-soluble polymer (X) and polymer particles contained in the binder composition of the present invention are, for example, formed by mixing the binder composition of the present invention and solid particles (electrode active material, conductive aid, etc.). In the layer, it is believed to function mainly as a binding agent (binder) that binds these solid particles together. It can also function as a binder that binds the current collector and the solid particles. Adsorption of the water-soluble polymer (X) and polymer particles to solid particles and current collectors includes not only physical adsorption but also chemical adsorption (adsorption due to formation of chemical bonds, adsorption due to transfer of electrons, etc.).
On the other hand, the water-soluble polymer (Y) contained in the binder composition of the invention is considered to function mainly as a thickener (dispersant) in the binder composition of the invention.
　本発明のバインダー組成物は、例えば、活物質を含む形態で電極シートを作製して、これを二次電池の電極に適用することで、電極シートの密着性を高め、かつ、二次電池のサイクル特性を向上させることができる。この理由は定かではないが、以下のように考えられる。
　本発明のバインダー組成物は水溶性高分子（Ｙ）を含有することにより増粘し、バインダー組成物の分散性が高められている。したがって、このバインダー組成物を用いて形成される電極活物質層中においても、水溶性高分子（Ｘ）、水溶性高分子（Ｙ）、重合体粒子及び活物質等の固体粒子が実質的に均一に分散して存在することができる。そして、水溶性高分子（Ｘ）がその特定の構造に起因して固体粒子等と相互作用しながら、重合体粒子よりも格段に硬い物性により電極活物質層の体積変化に抑制的に作用し、重合体粒子の固体粒子等に対する追従性と結着性を無理なく十分に引き出すことができることが、サイクル特性向上の一因と考えられる。 The binder composition of the present invention can be used, for example, by preparing an electrode sheet in a form containing an active material and applying it to the electrode of a secondary battery, thereby increasing the adhesion of the electrode sheet and improving the performance of the secondary battery. Cycle characteristics can be improved. Although the reason for this is not clear, it is considered as follows.
The binder composition of the present invention is thickened by containing the water-soluble polymer (Y), and the dispersibility of the binder composition is enhanced. Therefore, even in the electrode active material layer formed using this binder composition, solid particles such as water-soluble polymer (X), water-soluble polymer (Y), polymer particles, and active materials are substantially It can be distributed uniformly. Due to its specific structure, the water-soluble polymer (X) interacts with the solid particles and the like, and its physical properties are much harder than those of the polymer particles, thereby suppressing changes in the volume of the electrode active material layer. It is considered that one of the reasons for the improvement of the cycle characteristics is that the conformability and binding property of the polymer particles to the solid particles and the like can be brought out without difficulty.
（水溶性高分子（Ｘ））
　水溶性高分子（Ｘ）は、下記一般式（Ｂ－１）で表される構成成分及び／又は下記一般式（Ｂ－２）で表される構成成分を含む重合体（下記一般式（Ｂ－１）で表される構成成分及び下記一般式（Ｂ－２）で表される構成成分の少なくとも１種を含む重合体）である。重合体粒子の引張弾性率に対する水溶性高分子（Ｘ）の引張弾性率の比の値（「水溶性高分子（Ｘ）の引張弾性率」／「重合体粒子の引張弾性率」）は、１０を超え、１２以上であることが好ましい。一方、「水溶性高分子（Ｘ）の引張弾性率」／「重合体粒子の引張弾性率」は、４０以下であることが実際的であり、２５以下が好ましい。 (Water-soluble polymer (X))
The water-soluble polymer (X) is a polymer (general formula (B -1) and a polymer containing at least one component represented by the following general formula (B-2). The value of the ratio of the tensile elastic modulus of the water-soluble polymer (X) to the tensile elastic modulus of the polymer particles (“tensile elastic modulus of the water-soluble polymer (X)”/“tensile elastic modulus of the polymer particles”) is More than 10 and preferably 12 or more. On the other hand, the ratio of "tensile modulus of water-soluble polymer (X)"/"tensile modulus of polymer particles" is practically 40 or less, preferably 25 or less.
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000003
　一般式（Ｂ－１）中、Ｒ１１～Ｒ１３は水素原子、シアノ基又は炭素数１～６のアルキル基を示す。この炭素数１～６のアルキル基は直鎖でも分岐を有してもよい。この炭素数１～６のアルキル基は、炭素数１～４のアルキル基が好ましく、メチル又はエチルがより好ましく、メチルが更に好ましい。
　Ｒ１１及びＲ１２としては、水素原子が好ましい。
　Ｒ１３としては、水素原子又はメチルが好ましく、水素原子がより好ましい。
　Ｒ１４は水素原子、ヒドロキシ基、炭素数１～６のアルコキシ基（アルキルオキシ基）、シアノ基、フェニル基、カルボキシ基、スルホ基（－Ｓ（＝Ｏ）２（ＯＨ））、リン酸基（－ＯＰ（＝Ｏ）（ＯＨ）２）又はホスホン酸基（－Ｐ（＝Ｏ）（ＯＨ）２）を示す。上記の炭素数１～６のアルコキシ基中のアルキル基は直鎖でも分岐を有してもよい。この炭素数１～６のアルコキシ基は、炭素数１～４のアルコキシ基が好ましく、メトキシ又はエトキシがより好ましい。
　Ｒ１４としては、水素原子、ヒドロキシ基、メトキシ又はエトキシが好ましく、水素原子がより好ましい。
　Ｌ１１は単結合、炭素数１～１６のアルキレン基、炭素数６～１２のアリーレン基、酸素原子（－Ｏ－）、硫黄原子（－Ｓ－）、カルボニル基（＞Ｃ＝Ｏ）若しくはイミノ基（＞ＮＲＮ）、又はこれらを組み合わせた連結基を示す。また、後述のように、Ｌ１１は後記する置換基群Ｔから選ばれる置換基を有していてもよく、この置換基としては、ヒドロキシ基が好ましい。
　上記ＲＮは、水素原子又はアルキル基を示す。
　Ｌ１１が単結合以外の連結基を示す場合、Ｌ１１の化学式量は１４～２０００が好ましく、１４～５００がより好ましく、２８～２００が更に好ましい。Ｌ１１が有しうる炭素数１～１６のアルキレン基は直鎖でも分岐を有してもよい。この炭素数１～１６のアルキレン基は、炭素数１～１２のアルキレン基が好ましく、炭素数１～１０のアルキレン基がより好ましく、炭素数１～６のアルキレン基が更に好ましく、炭素数１～４のアルキレン基が特に好ましい。
　Ｌ１１としては、単結合、メチレン、エチレン、プロピレン、２－ヒドロキシプロピレン又はブチレンが好ましく、単結合、エチレン又はブチレンがより好ましい。
　＊は上記ポリマー（水溶性高分子（Ｘ））主鎖中に組み込まれるための結合部位を示す。 In general formula (B-1), R 11 to R 13 each represent a hydrogen atom, a cyano group or an alkyl group having 1 to 6 carbon atoms. This alkyl group having 1 to 6 carbon atoms may be linear or branched. The alkyl group having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 4 carbon atoms, more preferably methyl or ethyl, and still more preferably methyl.
A hydrogen atom is preferable as R 11 and R 12 .
R 13 is preferably a hydrogen atom or methyl, more preferably a hydrogen atom.
R 14 is a hydrogen atom, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms (alkyloxy group), a cyano group, a phenyl group, a carboxy group, a sulfo group (-S(=O) 2 (OH)), a phosphate group; (--OP(=O)(OH) 2 ) or phosphonic acid group (--P(=O)(OH) 2 ). The alkyl group in the alkoxy group having 1 to 6 carbon atoms may be linear or branched. The alkoxy group having 1 to 6 carbon atoms is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably methoxy or ethoxy.
R 14 is preferably a hydrogen atom, a hydroxy group, methoxy or ethoxy, more preferably a hydrogen atom.
L 11 is a single bond, an alkylene group having 1 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom (-O-), a sulfur atom (-S-), a carbonyl group (>C=O) or imino group (>NR N ) or a linking group combining these. In addition, as will be described later, L 11 may have a substituent selected from the substituent group T described later, and the substituent is preferably a hydroxy group.
RN represents a hydrogen atom or an alkyl group.
When L 11 represents a linking group other than a single bond, the chemical formula weight of L 11 is preferably 14-2000, more preferably 14-500, even more preferably 28-200. The alkylene group having 1 to 16 carbon atoms that L 11 may have may be linear or branched. The alkylene group having 1 to 16 carbon atoms is preferably an alkylene group having 1 to 12 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms, still more preferably an alkylene group having 1 to 6 carbon atoms, and 1 to 1 carbon atoms. An alkylene group of 4 is particularly preferred.
L 11 is preferably a single bond, methylene, ethylene, propylene, 2-hydroxypropylene or butylene, more preferably a single bond, ethylene or butylene.
* indicates a binding site for incorporation into the main chain of the polymer (water-soluble polymer (X)).
　一般式（Ｂ－２）中、Ｒ２１～Ｒ２３は上記Ｒ１１～Ｒ１３と同義であり、好ましい形態も同じである。すなわち、Ｒ２１及びＲ２２としては、水素原子が好ましく、Ｒ２３としては、水素原子又はメチルが好ましく、水素原子がより好ましい。
　Ｒ２４は水素原子、アシル基（アルキルカルボニル基）、ヒドロキシ基、フェニル基又はカルボキシ基を示す。アシル基中のアルキル基としては、例えば、Ｒ１１～Ｒ１３として採り得る炭素数１～６のアルキル基を採用することができる。
　Ｒ２４としては、水素原子又はヒドロキシ基が好ましく、水素原子がより好ましい。
　Ｌ２１は、上記Ｌ１１と同義であり、好ましい形態としてＬ１１の好ましい形態が挙げられ、単結合又はエチレンがより好ましく、単結合が更に好ましい。
　＊は上記ポリマー（水溶性高分子（Ｘ））主鎖中に組み込まれるための結合部位を示す。 In general formula (B-2), R 21 to R 23 have the same definitions as R 11 to R 13 above, and preferred forms are also the same. That is, R 21 and R 22 are preferably hydrogen atoms, R 23 is preferably a hydrogen atom or methyl, and more preferably a hydrogen atom.
R24 represents a hydrogen atom, an acyl group (alkylcarbonyl group), a hydroxy group, a phenyl group or a carboxy group. As the alkyl group in the acyl group, for example, an alkyl group having 1 to 6 carbon atoms that can be used as R 11 to R 13 can be employed.
R 24 is preferably a hydrogen atom or a hydroxy group, more preferably a hydrogen atom.
L 21 has the same definition as L 11 above, and preferred forms thereof include the preferred forms of L 11 , more preferably a single bond or ethylene, and still more preferably a single bond.
* indicates a binding site for incorporation into the main chain of the polymer (water-soluble polymer (X)).
　上記一般式（Ｂ－１）で表される構成成分の具体例としては、（メタ）アクリル酸成分；（メタ）アクリル酸メチル成分、（メタ）アクリル酸エチル成分、（メタ）アクリル酸プロピル成分及び（メタ）アクリル酸ブチル成分等の（メタ）アクリル酸アルキル成分；２－ヒドロキシエチル（メタ）アクリレート成分、４－ヒドロキシブチル（メタ）アクリレート成分、２，３－ジヒドロキシプロピル（メタ）アクリレート成分等のヒドロキシアルキル（メタ）アクリレート成分；メトキシエチル（メタ）アクリレート成分、エトキシエチル（メタ）アクリレート成分等のアルコキシアルキル（メタ）アクリレート成分が挙げられ、（メタ）アクリル酸成分、又は、ヒドロキシアルキル（メタ）アクリレート成分が好ましい。
　上記一般式（Ｂ－２）で表される構成成分の具体例としては、（メタ）アクリルアミド成分；Ｎ－（２－ヒドロキシエチル）（メタ）アクリルアミド成分等のＮ－（ヒドロキシアルキル）（メタ）アクリルアミド成分が挙げられ、（メタ）アクリルアミド成分が好ましく、アクリルアミド成分がより好ましい。 Specific examples of the component represented by the general formula (B-1) include (meth)acrylic acid component; methyl (meth)acrylate component, ethyl (meth)acrylate component, and propyl (meth)acrylate component. and alkyl (meth)acrylate components such as butyl (meth)acrylate component; 2-hydroxyethyl (meth)acrylate component, 4-hydroxybutyl (meth)acrylate component, 2,3-dihydroxypropyl (meth)acrylate component, etc. hydroxyalkyl (meth)acrylate component; alkoxyalkyl (meth)acrylate components such as methoxyethyl (meth)acrylate component and ethoxyethyl (meth)acrylate component, (meth)acrylic acid component, or hydroxyalkyl (meth) ) acrylate components are preferred.
Specific examples of the component represented by the general formula (B-2) include (meth)acrylamide component; N-(hydroxyalkyl)(meth) such as N-(2-hydroxyethyl)(meth)acrylamide component An acrylamide component may be mentioned, with a (meth)acrylamide component being preferred, and an acrylamide component being more preferred.
　水溶性高分子（Ｘ）は、電極活物質層の体積変化を効果的に抑制してサイクル特性を向上させる観点から、上記一般式（Ｂ－２）で表される構成成分を含むことが好ましく、アクリルアミド成分を含むことがより好ましい。 From the viewpoint of effectively suppressing the volume change of the electrode active material layer and improving the cycle characteristics, the water-soluble polymer (X) preferably contains a component represented by the general formula (B-2). , more preferably an acrylamide component.
　水溶性高分子（Ｘ）中におけるアクリルアミド成分の含有量は、６０質量％以上が好ましく、７０質量％以上がより好ましく、８０質量％以上が更に好ましく、８５質量％以上が特に好ましい。上限値に特に制限はなく、１００質量％とすることができる。 The content of the acrylamide component in the water-soluble polymer (X) is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 85% by mass or more. The upper limit is not particularly limited, and may be 100% by mass.
　本発明に用いられる水溶性高分子（Ｘ）は、本発明の効果を損なわない範囲内で、上記一般式（Ｂ－１）で表される構成成分及び／又は上記一般式（Ｂ－２）で表される構成成分以外の構成成分を含んでもよく、このような構成成分として、アクリロニトリル成分、Ｎ－ビニル－２－ピロリドン成分及びスチレン成分が挙げられ、アクリロニトリル成分が好ましい。
　なお、水溶性高分子（Ｘ）に含まれる構成成分の種類は特に制限されず、１～１０種が好ましく、１～５種がより好ましく、１種又は２種が更に好ましい。後述する水溶性高分子（Ｘ）の具体例では、構成成分の種類が１種又は２種の重合体を記載している。この具体例において、構成成分の種類が１種の重合体はポリアクリルアミドである。
　水溶性高分子（Ｘ）中、上記一般式（Ｂ－１）で表される構成成分及び／又は上記一般式（Ｂ－２）で表される構成成分の含有量は、合計で６０質量％以上が好ましく、７０質量％以上がより好ましく、８０質量％以上が更に好ましく、８５質量％以上が更に好ましく、９０質量％以上が更に好ましく、９５質量％以上が更に好ましく、１００質量％であってもよい。
　水溶性高分子（Ｘ）中、上記一般式（Ｂ－１）で表される構成成分の含有量は、４０質量％以下が好ましく、２０質量％未満がより好ましく、１５質量％以下が更に好ましい。一方、水溶性高分子（Ｘ）中、上記一般式（Ｂ－２）で表される構成成分の含有量は、６０質量％以上が好ましく、密着性及びサイクル特性をより向上させる観点から、８０質量％を超えることがより好ましく、８５質量％以上が更に好ましい。
　なお、水溶性高分子（Ｘ）が、上記一般式（Ｂ－１）で表される構成成分及び／又は上記一般式（Ｂ－２）で表される構成成分以外の構成成分（すなわち、上記一般式（Ｂ－１）で表される構成成分以外で、かつ、上記一般式（Ｂ－２）で表される構成成分以外の構成成分）を含む場合には、上記一般式（Ｂ－２）で表される構成成分の含有量は、６５質量％以上であることも好ましく、密着性及びサイクル特性をより向上させる観点から、７５質量％以上がより好ましい。
　水溶性高分子（Ｘ）が上記一般式（Ｂ－１）で表される構成成分と上記一般式（Ｂ－２）で表される構成成分とを含む場合、水溶性高分子（Ｘ）中、上記一般式（Ｂ－１）で表される構成成分の含有量に対する上記一般式（Ｂ－２）で表される構成成分の含有量の質量比（上記一般式（Ｂ－２）で表される構成成分の含有量／上記一般式（Ｂ－１）で表される構成成分の含有量）は特に制限されず、９９／１～６０／４０が好ましい。 The water-soluble polymer (X) used in the present invention is a component represented by the general formula (B-1) and/or the general formula (B-2) within a range that does not impair the effects of the present invention. It may contain constituents other than the constituents represented by and examples of such constituents include an acrylonitrile component, an N-vinyl-2-pyrrolidone component and a styrene component, with the acrylonitrile component being preferred.
The types of constituent components contained in the water-soluble polymer (X) are not particularly limited, and are preferably 1 to 10 types, more preferably 1 to 5 types, and even more preferably 1 or 2 types. Specific examples of the water-soluble polymer (X) described later describe polymers having one or two types of constituent components. In this embodiment, the one-component polymer is polyacrylamide.
In the water-soluble polymer (X), the content of the component represented by the general formula (B-1) and/or the component represented by the general formula (B-2) is 60% by mass in total. is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 85% by mass or more, still more preferably 90% by mass or more, still more preferably 95% by mass or more, and 100% by mass. good too.
The content of the component represented by the general formula (B-1) in the water-soluble polymer (X) is preferably 40% by mass or less, more preferably less than 20% by mass, and even more preferably 15% by mass or less. . On the other hand, in the water-soluble polymer (X), the content of the component represented by the general formula (B-2) is preferably 60% by mass or more, and from the viewpoint of further improving adhesion and cycle characteristics, it is 80% by mass. More preferably, it exceeds 85% by mass, and more preferably 85% by mass or more.
The water-soluble polymer (X) is a component other than the component represented by the general formula (B-1) and/or the component represented by the general formula (B-2) (that is, the Other than the constituents represented by the general formula (B-1), and the constituents other than the constituents represented by the general formula (B-2)), the general formula (B-2 ) is preferably 65% by mass or more, and more preferably 75% by mass or more from the viewpoint of further improving adhesion and cycle characteristics.
When the water-soluble polymer (X) contains a component represented by the general formula (B-1) and a component represented by the general formula (B-2), in the water-soluble polymer (X) , the mass ratio of the content of the component represented by the general formula (B-2) to the content of the component represented by the general formula (B-1) (represented by the general formula (B-2) The content of the component represented by the general formula (B-1)/the content of the component represented by the general formula (B-1)) is not particularly limited, and is preferably 99/1 to 60/40.
　本発明に用いられる水溶性高分子（Ｘ）の重量平均分子量（Ｍｗ）は特に制限されず、サイクル特性向上の観点から、１０００００～９０００００が好ましく、２０００００～５０００００がより好ましい。
　水溶性高分子（Ｘ）は架橋構造を有しないこと、すなわち、鎖状高分子であることが好ましい。 The weight average molecular weight (Mw) of the water-soluble polymer (X) used in the present invention is not particularly limited, and is preferably 100,000 to 900,000, more preferably 200,000 to 500,000, from the viewpoint of improving cycle characteristics.
It is preferable that the water-soluble polymer (X) does not have a crosslinked structure, that is, it is a chain polymer.
　また、サイクル特性向上の観点から、水溶性高分子（Ｘ）の分子量分布（分散度とも称され、［重量平均分子量（Ｍｗ）］／［数平均分子量（Ｍｎ）］により算出される。）は、５．０以下が好ましく、３．０以下がより好ましい。一方、分子量分布は１．０以上が実際的である。 Further, from the viewpoint of improving cycle characteristics, the molecular weight distribution of the water-soluble polymer (X) (also called dispersity, calculated by [weight average molecular weight (Mw)]/[number average molecular weight (Mn)]) is , is preferably 5.0 or less, more preferably 3.0 or less. On the other hand, the practical molecular weight distribution is 1.0 or more.
（重量平均分子量、数平均分子量の測定）
　本発明において、ポリマーの重量平均分子量及び数平均分子量については、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）によって測定する。分子量は、ポリエチレンオキシド換算の分子量をいう。その測定法としては、基本として下記測定条件１の方法により測定した値とする。ただし、ポリマーの種類によっては適宜適切な溶離液を選定して用いればよい。
（測定条件１）
　　測定器：ＨＬＣ－８２２０ＧＰＣ（商品名、東ソー社製）
　　カラム：ＴＯＳＯＨ　ＴＳＫｇｅｌ　５０００ＰＷＸＬ（商品名、東ソー社製）、ＴＯＳＯＨ　ＴＳＫｇｅｌ　Ｇ４０００ＰＷＸＬ（商品名、東ソー社製）、ＴＯＳＯＨ　ＴＳＫｇｅｌ　Ｇ２５００ＰＷＸＬ（商品名、東ソー社製）をつなげる。
　　キャリア：２００ｍＭ　硝酸ナトリウム水溶液
　　測定温度：４０℃
　　キャリア流量：１．０ｍｌ／ｍｉｎ
　　試料濃度：０．２質量％
　　検出器：ＲＩ（屈折率）検出器
　架橋がかかっている場合など、上記測定条件１で分子量が測れない場合は下記測定条件２で静的光散乱により、分子量を測定する。
（測定条件２）
　　測定器：ＤＬＳ－８０００（商品名、大塚電子社製）
　　測定濃度：０．２５、０．５０、０．７５、１．００ｍｇ／ｍＬ
　　希釈液：０．１Ｍ　ＮａＣｌ水溶液
　　レーザー波長：６３３ｎｍ
　　ピンホール：ＰＨ１＝Ｏｐｅｎ、ＰＨ２＝Ｓｌｉｔ
　　測定角度：６０、７０、８０、９０、１００、１１０、１２０、１３０度
　　解析法：Ｚｉｍｍ平方根プロットより、分子量を測定する。解析に必要なｄｎ／ｄｃはＡｂｂｅ屈折率計で実測する。 (Measurement of weight average molecular weight and number average molecular weight)
In the present invention, the weight average molecular weight and number average molecular weight of the polymer are measured by gel permeation chromatography (GPC). Molecular weight refers to molecular weight in terms of polyethylene oxide. As a method for the measurement, the values are basically measured according to the method of measurement condition 1 below. However, depending on the type of polymer, an appropriate eluent may be selected and used.
(Measurement condition 1)
Measuring instrument: HLC-8220GPC (trade name, manufactured by Tosoh Corporation)
Column: TOSOH TSKgel 5000PWXL (trade name, manufactured by Tosoh Corporation), TOSOH TSKgel G4000PWXL (trade name, manufactured by Tosoh Corporation), and TOSOH TSKgel G2500PWXL (trade name, manufactured by Tosoh Corporation) are connected.
Carrier: 200 mM sodium nitrate aqueous solution Measurement temperature: 40°C
Carrier flow rate: 1.0 ml/min
Sample concentration: 0.2% by mass
Detector: RI (refractive index) detector If the molecular weight cannot be measured under the measurement condition 1 above, such as when cross-linking is applied, the molecular weight is measured by static light scattering under the measurement condition 2 below.
(Measurement condition 2)
Measuring instrument: DLS-8000 (trade name, manufactured by Otsuka Electronics Co., Ltd.)
Measurement concentration: 0.25, 0.50, 0.75, 1.00 mg/mL
Diluent: 0.1 M NaCl aqueous solution Laser wavelength: 633 nm
Pinhole: PH1=Open, PH2=Slit
Measurement angle: 60, 70, 80, 90, 100, 110, 120, 130 degrees Analysis method: Molecular weight is measured from Zimm square root plot. dn/dc required for analysis is actually measured with an Abbe refractometer.
　本発明に用いられる水溶性高分子（Ｘ）は、電極活物質層の体積変化を効果的に抑制してサイクル特性を向上させる観点から、引張弾性率が３５００ＭＰａ以上であることが好ましく、４０００ＭＰａ以上がより好ましく、５０００ＭＰａ以上が更に好ましく、６０００ＭＰａ以上が特に好ましい。一方、引張弾性率は１５０００ＭＰａ以下が実際的である。
　本発明において、上記引張弾性率は後記実施例に記載の方法により得られる値とする。 The water-soluble polymer (X) used in the present invention preferably has a tensile modulus of 3500 MPa or more, preferably 4000 MPa or more, from the viewpoint of effectively suppressing volume change of the electrode active material layer and improving cycle characteristics. is more preferable, 5000 MPa or more is still more preferable, and 6000 MPa or more is particularly preferable. On the other hand, it is practical that the tensile modulus is 15000 MPa or less.
In the present invention, the tensile modulus is a value obtained by the method described in Examples below.
　上記水溶性高分子（Ｘ）は、上述した各構造ないし部分構造において更に置換基を有していてもよく、この置換基としては、下記置換基群Ｔから選ばれる置換基が挙げられる。また、水溶性高分子（Ｘ）における各置換基については、特段の断りのない限り、下記置換基群Ｔにおける対応する置換基の記載を適用することができる。水溶性高分子（Ｘ）における各連結基についても、特段の断りのない限り、下記置換基群Ｔにおける対応する置換基から水素結合を除いて得られる連結基の記載を適用することができる。 The water-soluble polymer (X) may further have a substituent in each structure or partial structure described above, and examples of the substituent include substituents selected from the following substituent group T. Further, with respect to each substituent in the water-soluble polymer (X), unless otherwise specified, the description of the corresponding substituent in the following substituent group T can be applied. For each linking group in the water-soluble polymer (X), unless otherwise specified, the description of the linking group obtained by removing the hydrogen bond from the corresponding substituent in the following substituent group T can be applied.
－　置換基群Ｔ　－
　アルキル基（好ましくは炭素数が１～２０であるアルキル基、例えばメチル、エチル、イソプロピル、ｔ－ブチル、ペンチル、ヘプチル、１－エチルペンチル、ベンジル、２－エトキシエチル、１－カルボキシメチル等）、アルケニル基（好ましくは炭素数が２～２０であるアルケニル基、例えば、ビニル、アリル、オレイル等）、アルキニル基（好ましくは炭素数が２～２０であるアルキニル基、例えば、エチニル、ブタジイニル、フェニルエチニル等）、シクロアルキル基（好ましくは炭素数が３～２０であるシクロアルキル基、例えば、シクロプロピル、シクロペンチル、シクロヘキシル、４－メチルシクロヘキシル等）、アリール基（好ましくは炭素数が６～２６であるアリール基、例えば、フェニル、１－ナフチル、４－メトキシフェニル、２－クロロフェニル、３－メチルフェニル等）、ヘテロ環基（好ましくは炭素数が２～２０であるヘテロ環基で、より好ましくは、酸素原子、硫黄原子及び窒素原子の少なくとも１種を環構成原子として有する５又は６員のヘテロ環基である。ヘテロ環基は芳香族ヘテロ環基及び脂肪族ヘテロ環基を含む。例えば、テトラヒドロピラン環基、テトラヒドロフラン環基、２－ピリジル、４－ピリジル、２－イミダゾリル、２－ベンゾイミダゾリル、２－チアゾリル、２－オキサゾリル等）、アルコキシ基（好ましくは炭素数が１～２０であるアルコキシ基、例えば、メトキシ、エトキシ、イソプロピルオキシ、ベンジルオキシ等）、アリールオキシ基（好ましくは炭素数が６～２６であるアリールオキシ基、例えば、フェノキシ、１－ナフチルオキシ、３－メチルフェノキシ、４－メトキシフェノキシ等）、ヘテロ環オキシ基（上記ヘテロ環基に－Ｏ－基が結合した基）、アルコキシカルボニル基（好ましくは炭素数が２～２０であるアルコキシカルボニル基、例えば、エトキシカルボニル、２－エチルヘキシルオキシカルボニル等）、アリールオキシカルボニル基（好ましくは炭素数が７～２６であるアリールオキシカルボニル基、例えば、フェノキシカルボニル、１－ナフチルオキシカルボニル、３－メチルフェノキシカルボニル、４－メトキシフェノキシカルボニル等）、アミノ基（好ましくは炭素数が０～２０であるアミノ基であり、アルキル基及びアリール基から選択される基で置換されたアミノ基を含む。例えば、アミノ（－ＮＨ２）、Ｎ，Ｎ－ジメチルアミノ、Ｎ，Ｎ－ジエチルアミノ、Ｎ－エチルアミノ、アニリノ等）、スルファモイル基（好ましくは炭素数が０～２０であるスルファモイル基であり、アルキル基及びアリール基から選択される基で置換されたスルファモイル基を含む。例えば、スルファモイル（－ＳＯ２ＮＨ２）、Ｎ，Ｎ－ジメチルスルファモイル、Ｎ－フェニルスルファモイル等）、アシル基（アルキルカルボニル基、アルケニルカルボニル基、アルキニルカルボニル基、アリールカルボニル基及びヘテロ環カルボニル基を含み、好ましくは炭素数が１～２０であるアシル基、例えば、ホルミル、アセチル、プロピオニル、ブチリル、オクタノイル、ヘキサデカノイル、アクリロイル、メタクリロイル、クロトノイル、ベンゾイル、ナフトイル、ニコチノイル等）、アシルオキシ基（アルキルカルボニルオキシ基、アルケニルカルボニルオキシ基、アルキニルカルボニルオキシ基、アリールカルボニルオキシ基及びヘテロ環カルボニルオキシ基を含み、好ましくは炭素数が１～２０であるアシルオキシ基、例えば、ホルミルオキシ、アセチルオキシ、プロピオニルオキシ、ブチリルオキシ、オクタノイルオキシ、ヘキサデカノイルオキシ、アクリロイルオキシ、メタクリロイルオキシ、クロトノイルオキシ、ベンゾイルオキシ、ナフトイルオキシ、ニコチノイルオキシ等）、カルバモイル基（好ましくは炭素数が１～２０であるカルバモイル基であり、アルキル基及びアリール基から選択される基で置換されたカルバモイル基を含む。例えば、Ｎ，Ｎ－ジメチルカルバモイル、Ｎ－フェニルカルバモイル等）、アシルアミノ基（好ましくは炭素数が１～２０であるアシルアミノ基であり、アシルアミノ基におけるアシル基としては、上記アシル基が好ましく挙げられる。例えば、アセチルアミノ、ベンゾイルアミノ等）、アルキルチオ基（好ましくは炭素数が１～２０であるアルキルチオ基、例えば、メチルチオ、エチルチオ、イソプロピルチオ、ベンジルチオ等）、アリールチオ基（好ましくは炭素数が６～２６であるアリールチオ基、例えば、フェニルチオ、１－ナフチルチオ、３－メチルフェニルチオ、４－メトキシフェニルチオ等）、アリールシリル基（好ましくは炭素数が６～４２であるアリールシリル基、例えば、トリフェニルシリル等）、ヘテロ環チオ基（上記ヘテロ環基に－Ｓ－基が結合した基）、アルキルスルホニル基（好ましくは炭素数が１～２０であるアルキルスルホニル基、例えば、メチルスルホニル、エチルスルホニル等）、アリールスルホニル基（好ましくは炭素数が６～２２であるアリールスルホニル基、例えば、ベンゼンスルホニル等）、アルキルシリル基（好ましくは炭素数が１～２０であるアルキルシリル基、例えば、モノメチルシリル、ジメチルシリル、トリメチルシリル、トリエチルシリル等）、亜リン酸基（好ましくは炭素数が０～２０である亜リン酸基、例えば、－ＯＰ（＝Ｏ）（－ＯＨ）（ＲＰ））、次亜リン酸基（好ましくは炭素数が０～２０である次亜リン酸基、例えば、－ＯＰ（＝Ｏ）（ＲＰ）２）、ホスホリル基（好ましくは炭素数が０～２０であるホスホリル基、例えば、－Ｐ（＝Ｏ）（ＲＰ）２）、ホスフィニル基（好ましくは炭素数が０～２０であるホスフィニル基、例えば、－Ｐ（ＲＰ）２）、スルホ基、リン酸基、ホスホン酸基、カルボキシ基、ヒドロキシ基、スルファニル基、シアノ基、ハロゲン原子（例えばフッ素原子、塩素原子、臭素原子、ヨウ素原子）が挙げられる。ＲＰは、水素原子又は置換基（好ましくは置換基群Ｔから選択される基）である。
　また、これらの置換基群Ｔで挙げた各基は、上記置換基群Ｔで挙げた各基を更に置換基として有していてもよい。 - Substituent group T -
alkyl groups (preferably alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), alkenyl groups (preferably alkenyl groups having 2 to 20 carbon atoms, such as vinyl, allyl, oleyl, etc.), alkynyl groups (preferably alkynyl groups having 2 to 20 carbon atoms, such as ethynyl, butadiynyl, phenylethynyl etc.), cycloalkyl groups (preferably cycloalkyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.), aryl groups (preferably having 6 to 26 carbon atoms aryl groups such as phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, etc.), heterocyclic groups (preferably heterocyclic groups having 2 to 20 carbon atoms, more preferably It is a 5- or 6-membered heterocyclic group having at least one of an oxygen atom, a sulfur atom and a nitrogen atom as a ring-constituting atom, and the heterocyclic group includes an aromatic heterocyclic group and an aliphatic heterocyclic group, such as tetrahydro pyran ring group, tetrahydrofuran ring group, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, etc.), alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, methoxy, ethoxy, isopropyloxy, benzyloxy, etc.), aryloxy groups (preferably aryloxy groups having 6 to 26 carbon atoms, such as phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy) etc.), a heterocyclic oxy group (a group in which an —O— group is bonded to the above heterocyclic group), an alkoxycarbonyl group (preferably an alkoxycarbonyl group having 2 to 20 carbon atoms, such as ethoxycarbonyl, 2-ethylhexyloxy carbonyl, etc.), aryloxycarbonyl group (preferably an aryloxycarbonyl group having 7 to 26 carbon atoms, such as phenoxycarbonyl, 1-naphthyloxycarbonyl, 3-methylphenoxycarbonyl, 4-methoxyphenoxycarbonyl, etc.), amino group (preferably an amino group having 0 to 20 carbon atoms, including an amino group substituted with a group selected from an alkyl group and an aryl group. For example, amino (—NH 2 ), N,N-dimethyl amino, N,N-diethylamino, N-ethylamino, anilino, etc.), sulfamoyl group (preferably a sulfamoyl group having 0 to 20 carbon atoms, substituted with a group selected from an alkyl group and an aryl group) including groups. For example, sulfamoyl (—SO 2 NH 2 ), N,N-dimethylsulfamoyl, N-phenylsulfamoyl, etc.), acyl groups (alkylcarbonyl groups, alkenylcarbonyl groups, alkynylcarbonyl groups, arylcarbonyl groups and heterocyclic Acyl groups containing carbonyl groups, preferably having 1 to 20 carbon atoms, such as formyl, acetyl, propionyl, butyryl, octanoyl, hexadecanoyl, acryloyl, methacryloyl, crotonoyl, benzoyl, naphthoyl, nicotinoyl, etc.), acyloxy groups (Including an alkylcarbonyloxy group, an alkenylcarbonyloxy group, an alkynylcarbonyloxy group, an arylcarbonyloxy group and a heterocyclic carbonyloxy group, preferably an acyloxy group having 1 to 20 carbon atoms, such as formyloxy, acetyloxy, propionyloxy, butyryloxy, octanoyloxy, hexadecanoyloxy, acryloyloxy, methacryloyloxy, crotonoyloxy, benzoyloxy, naphthoyloxy, nicotinoyloxy, etc.), carbamoyl group (preferably having 1 to 20 carbon atoms) A carbamoyl group, including a carbamoyl group substituted with a group selected from an alkyl group and an aryl group, such as N,N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.), an acylamino group (preferably having 1 to 20, and the acyl group in the acylamino group is preferably the above acyl group, such as acetylamino, benzoylamino, etc.), an alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms, methylthio, ethylthio, isopropylthio, benzylthio, etc.), arylthio groups (preferably arylthio groups having 6 to 26 carbon atoms, such as phenylthio, 1-naphthylthio, 3-methylphenylthio, 4-methoxyphenylthio, etc.) , an arylsilyl group (preferably an arylsilyl group having 6 to 42 carbon atoms, such as triphenylsilyl, etc.), a heterocyclic thio group (a group in which a -S- group is bonded to the above heterocyclic group), an alkylsulfonyl group (preferably an alkylsulfonyl group having 1 to 20 carbon atoms, such as methylsulfonyl, ethylsulfonyl, etc.), an arylsulfonyl group (preferably an arylsulfonyl group having 6 to 22 carbon atoms, such as benzenesulfonyl, etc.), Alkylsilyl groups (preferably alkylsilyl groups having 1 to 20 carbon atoms, such as monomethylsilyl, dimethylsilyl, trimethylsilyl, triethylsilyl, etc.), phosphorous groups (preferably phosphorous groups having 0 to 20 carbon atoms, Acid groups, such as —OP(=O)(—OH)(R P )), hypophosphite groups (preferably hypophosphite groups having 0 to 20 carbon atoms, such as —OP(=O )(R P ) 2 ), phosphoryl group (preferably a phosphoryl group having 0 to 20 carbon atoms, such as —P(=O)(R P ) 2 ), phosphinyl group (preferably having 0 to 20 carbon atoms is a phosphinyl group, such as —P(R P ) 2 ), a sulfo group, a phosphoric acid group, a phosphonic acid group, a carboxy group, a hydroxy group, a sulfanyl group, a cyano group, a halogen atom (such as a fluorine atom, a chlorine atom, a bromine atom, iodine atom). R P is a hydrogen atom or a substituent (preferably a group selected from Substituent Group T).
In addition, each group listed in these substituent group T may further have each group listed in the above substituent group T as a substituent.
　本発明に用いられる水溶性高分子（Ｘ）は、通常のポリマーの合成方法により得ることができる。本発明に用いられる水溶性高分子（Ｘ）の合成において、連鎖重合等の方法及び条件は、特に限定されず、通常の方法及び条件を、目的に応じて適宜に適用することができる。
　なお、水溶性高分子（Ｘ）の「水溶性」は、例えば、構成成分の種類及びその含有量によって制御することができる。 The water-soluble polymer (X) used in the present invention can be obtained by a conventional polymer synthesis method. In the synthesis of the water-soluble polymer (X) used in the present invention, the method and conditions for chain polymerization and the like are not particularly limited, and ordinary methods and conditions can be appropriately applied depending on the purpose.
The "water-solubility" of the water-soluble polymer (X) can be controlled by, for example, the types and contents of constituent components.
　本発明に用いる水溶性高分子（Ｘ）の好ましい具体例を以下に示すが、本発明はこれらに限定して解釈されるものではない。下記具体例において、ａ及びｂは各構成成分の割合（質量％）を示す。ａ＝９９～６０であり、ｂ＝１～４０である。ただし、ａ＋ｂ＝１００である。 Preferable specific examples of the water-soluble polymer (X) used in the present invention are shown below, but the present invention should not be construed as being limited to these. In the following specific examples, a and b indicate the ratio (% by mass) of each component. a=99-60 and b=1-40. However, a+b=100.
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
　本発明において、水溶性高分子（Ｘ）は１種単独で用いてもよく、２種以上を組み合わせて用いてもよい。 In the present invention, the water-soluble polymer (X) may be used singly or in combination of two or more.
（水溶性高分子（Ｙ））
　本発明において、水溶性高分子（Ｙ）は、上述の水溶性高分子（Ｘ）とは構造の異なる水溶性の高分子であり、二次電池の電極活物質層形成用スラリーの増粘剤として機能するものを広く用いることができる。上記増粘剤として例えば、セルロース化合物及び天然多糖類等の多糖類が挙げられる。
　セルロース化合物としては、例えばメチルセルロース、エチルセルロース、ベンジルセルロース、トリエチルセルロース、シアノエチルセルロース、ニトロセルロース、ヒドロキシメチルセルロース、ヒドロキシエチルセルロース（ＨＥＣ）、ヒドロキシプロピルセルロース（ＨＰＣ）、ヒドロキシプロピルメチルセルロース（ＨＰＭＣ）、ヒドロキシブチルメチルセルロース、カルボキシメチルセルロース（ＣＭＣ）、アミノメチルヒドロキシプロピルセルロース、アミノエチルヒドロキシプロピルセルロース、セルロースナノファイバー（ＣＮＦ）、セルロースナノクリスタル（ＣＮＣ）等が挙げられる。また、セルロース化合物は、アンモニウム塩、ナトリウム塩、リチウム塩等の塩の態様であってもよい。
　天然多糖類としては、例えばカラギナン、キサンタンガム、グァーガム、タマリンドガム（タマリンドシードガム）、ダイユータンガム、ウェランガム、ジェランガム、ローカストビーンガム、タラガム等が挙げられる。
　これらの中でも、水溶性高分子（Ｙ）は、カルボキシメチルセルロース、セルロースナノファイバー、ヒドロキシエチルセルロース、ヒドロキシプロピルセルロース及びキサンタンガムの少なくとも１種を含むことが好ましい。
　本発明において、水溶性高分子（Ｙ）は１種単独で用いてもよく、２種以上を組み合わせて用いてもよい。 (Water-soluble polymer (Y))
In the present invention, the water-soluble polymer (Y) is a water-soluble polymer having a structure different from that of the water-soluble polymer (X) described above, and is used as a thickening agent for slurry for forming an electrode active material layer of a secondary battery. can be used widely. Examples of the thickener include cellulose compounds and polysaccharides such as natural polysaccharides.
Cellulose compounds include, for example, methylcellulose, ethylcellulose, benzylcellulose, triethylcellulose, cyanoethylcellulose, nitrocellulose, hydroxymethylcellulose, hydroxyethylcellulose (HEC), hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC), hydroxybutylmethylcellulose, carboxy Methylcellulose (CMC), aminomethylhydroxypropylcellulose, aminoethylhydroxypropylcellulose, cellulose nanofiber (CNF), cellulose nanocrystal (CNC) and the like. Moreover, the cellulose compound may be in the form of a salt such as an ammonium salt, sodium salt, or lithium salt.
Examples of natural polysaccharides include carrageenan, xanthan gum, guar gum, tamarind gum (tamarind seed gum), diutan gum, welan gum, gellan gum, locust bean gum, and tara gum.
Among these, the water-soluble polymer (Y) preferably contains at least one of carboxymethylcellulose, cellulose nanofibers, hydroxyethylcellulose, hydroxypropylcellulose and xanthan gum.
In the present invention, the water-soluble polymer (Y) may be used singly or in combination of two or more.
（重合体粒子）
　本発明に用いられる重合体粒子は粒子状のポリマーであり、「粒子状」は、偏平状、無定形等であってもよく、球状若しくは顆粒状が好ましい。
　なお、重合体粒子は非水溶性高分子である。すなわち、重合体粒子は２０℃において水に対する溶解度が１０ｇ／Ｌ－Ｈ２Ｏ未満である（水１リットルに対して１０ｇ以上溶解しない）ポリマーである。 (Polymer particles)
The polymer particles used in the present invention are particulate polymers, and "particulate" may be flat, amorphous, or the like, preferably spherical or granular.
Incidentally, the polymer particles are water-insoluble polymers. That is, the polymer particles are polymers that have a solubility in water of less than 10 g/L-H 2 O at 20° C. (no more than 10 g dissolved in 1 liter of water).
　重合体粒子の引張弾性率は、「水溶性高分子（Ｘ）の引張弾性率」／「重合体粒子の引張弾性率」が１０を超えれば特に制限されず、固体粒子同士又は集電体と固体粒子との密着性を高めて電極シートの密着性及びサイクル特性を向上させる観点から、１００～３０００ＭＰａが好ましく、１００～１０００ＭＰａがより好ましい。本発明において、上記引張弾性率は後記実施例に記載の方法により得られる値とする。 The tensile elastic modulus of the polymer particles is not particularly limited as long as the "tensile elastic modulus of the water-soluble polymer (X)"/"the tensile elastic modulus of the polymer particles" exceeds 10. From the viewpoint of enhancing the adhesion to the solid particles and improving the adhesion and cycle characteristics of the electrode sheet, the pressure is preferably 100 to 3000 MPa, more preferably 100 to 1000 MPa. In the present invention, the tensile modulus is a value obtained by the method described in Examples below.
　重合体粒子のガラス転移温度は特に制限されず、電極シートの密着性及びサイクル特性向上の観点から、－５０～１５０℃が好ましく、－３０～１００℃がより好ましい。
　なお、重合体粒子がガラス転移温度を２点以上有する場合には、その全てが上記好ましい範囲内に入ることが好ましい。 The glass transition temperature of the polymer particles is not particularly limited, and is preferably -50 to 150°C, more preferably -30 to 100°C, from the viewpoint of improving adhesion of the electrode sheet and cycle characteristics.
When the polymer particles have two or more glass transition temperatures, all of them are preferably within the above preferred range.
―ガラス転移温度―
　市販品の重合体粒子を用いる場合、重合体粒子のガラス転移温度は製造元のカタログ記載の値を採用する。
　製造元のガラス転移温度の情報が入手できない場合又は合成した重合体粒子を用いる場合は、文献ＰＯＬＹＭＥＲ　ＨＡＮＤＢＯＯＫ　４ｔｈ、３６章の表のガラス転移温度を採用する。上記文献にガラス転移温度が記載されていない場合は下記測定条件で測定して得られるガラス転移温度を採用する。 -Glass-transition temperature-
When using commercially available polymer particles, the value described in the manufacturer's catalog is adopted as the glass transition temperature of the polymer particles.
If the manufacturer's glass transition temperature information is not available or if synthetic polymer particles are used, the glass transition temperature table in the literature POLYMER HANDBOOK 4th, chapter 36 is adopted. When the glass transition temperature is not described in the above document, the glass transition temperature obtained by measuring under the following measurement conditions is adopted.
　ガラス転移温度（Ｔｇ）は、重合体粒子の乾燥試料を用いて、示差走査熱量計：Ｘ－ＤＳＣ７０００（商品名、ＳＩＩ・ナノテクノロジー社製）を用いて下記測定条件で測定のうえ算出する。測定は同一の試料で二回実施し、二回目の測定結果を採用する。
（測定条件）
　　測定室内の雰囲気：窒素ガス（５０ｍＬ／ｍｉｎ）
　　昇温速度：５℃／ｍｉｎ
　　測定開始温度：－８０℃
　　測定終了温度：２５０℃
　　試料パン：アルミニウム製パン
　　測定試料の質量：５ｍｇ
　　Ｔｇの算出：ＤＳＣ（示差走査熱量測定）チャートの下降開始点と下降終了点の中間温度の小数点以下を四捨五入することでＴｇを算出する。 The glass transition temperature (Tg) is calculated by measuring a dry sample of polymer particles with a differential scanning calorimeter: X-DSC7000 (trade name, manufactured by SII Nano Technology Co., Ltd.) under the following measurement conditions. The same sample is measured twice, and the result of the second measurement is adopted.
(Measurement condition)
Atmosphere in measurement chamber: Nitrogen gas (50 mL/min)
Heating rate: 5°C/min
Measurement start temperature: -80°C
Measurement end temperature: 250°C
Sample pan: Aluminum pan Mass of measurement sample: 5 mg
Calculation of Tg: Tg is calculated by rounding off the decimal point of the intermediate temperature between the start point and the end point of the drop on the DSC (differential scanning calorimetry) chart.
　重合体粒子の平均粒径（平均一次粒子径）は、特に制限されず、５０～３００ｎｍが好ましく、５０～２５０ｎｍがより好ましく、５０～２００ｎｍが更に好ましい。
　市販品の重合体粒子を用いる場合、重合体粒子の平均粒径は製造元のカタログ記載の値を採用する。
　製造元の平均粒径の情報が入手できない場合又は合成した重合体粒子を用いる場合は、重合体粒子の平均粒径は、後述する負極活物質の平均粒径（水中での体積基準のメジアン径Ｄ５０）の測定方法を適用して得られた値を採用すればよい。 The average particle size (average primary particle size) of the polymer particles is not particularly limited, and is preferably 50 to 300 nm, more preferably 50 to 250 nm, even more preferably 50 to 200 nm.
When using commercially available polymer particles, the average particle size of the polymer particles is the value described in the manufacturer's catalog.
When information on the average particle size of the manufacturer is not available or when synthetic polymer particles are used, the average particle size of the polymer particles is the average particle size of the negative electrode active material (volume-based median diameter in water D50 ) can be used.
　重合体粒子は逐次重合ポリマー粒子及び連鎖重合ポリマー粒子のいずれでもよく、連鎖重合ポリマー粒子が好ましい。連鎖重合ポリマー粒子は、ホモポリマーでもよく、コポリマーでもよい。コポリマーの重合形態はランダム及びブロックのいずれでもよい。
　重合体粒子（連鎖重合ポリマー）の構成成分としては、例えば、共役ジエン成分、芳香族ビニルモノマー成分、エチレン性不飽和カルボン酸成分、シアノ基含有エチレン性モノマー成分、エチレン性不飽和カルボン酸エステル成分及びフッ化ビニルモノマー成分が挙げられ、共役ジエン成分、エチレン性不飽和カルボン酸成分、シアノ基含有エチレン性モノマー成分及び芳香族ビニルモノマー成分の少なくとも１種を含むことが好ましい。重合体粒子は、上記構成成分の中でも共役ジエン成分及び芳香族ビニルモノマー成分を有することが好ましい。
　上記において、芳香族ビニルモノマー成分とは炭素－炭素二重結合（好ましくは１つ又は２つ、より好ましくは１つ）とアリール基（好ましくは１つ）とを有するモノマー由来の成分を意味し、エチレン性不飽和カルボン酸成分とは炭素－炭素二重結合（好ましくは１つ）とカルボキシ基（好ましくは１つ又は２つ）とを有するモノマー由来の成分を意味し、シアノ基含有エチレン性モノマー成分とは炭素－炭素二重結合（好ましくは１つ）とシアノ基（好ましくは１つ又は２つ、より好ましくは１つ）とを有するモノマー由来の成分を意味し、エチレン性不飽和カルボン酸エステル成分とは炭素－炭素二重結合（好ましくは１つ）とカルボン酸エステル部位（エステル化されたカルボキシ基）（好ましくは１つ）とを有するモノマー由来の成分を意味し、フッ化ビニルモノマー成分とは１～４個（好ましくは２個）のフッ素原子を有するエチレン由来の成分を意味する。
　なお、上記「炭素－炭素二重結合」には、芳香族環の炭素－炭素二重結合は含まれない。 The polymer particles may be either sequentially polymerized polymer particles or chain polymerized polymer particles, preferably chain polymerized polymer particles. The chain polymer particles may be homopolymers or copolymers. The polymerization form of the copolymer may be either random or block.
Constituents of the polymer particles (chain polymerization polymer) include, for example, a conjugated diene component, an aromatic vinyl monomer component, an ethylenically unsaturated carboxylic acid component, a cyano group-containing ethylenic monomer component, and an ethylenically unsaturated carboxylic acid ester component. and fluorinated vinyl monomer components, and preferably contain at least one of a conjugated diene component, an ethylenically unsaturated carboxylic acid component, a cyano group-containing ethylenic monomer component and an aromatic vinyl monomer component. The polymer particles preferably have a conjugated diene component and an aromatic vinyl monomer component among the above components.
In the above, the aromatic vinyl monomer component means a component derived from a monomer having a carbon-carbon double bond (preferably one or two, more preferably one) and an aryl group (preferably one). , The ethylenically unsaturated carboxylic acid component means a component derived from a monomer having a carbon-carbon double bond (preferably one) and a carboxy group (preferably one or two), and a cyano group-containing ethylenic A monomer component means a component derived from a monomer having a carbon-carbon double bond (preferably one) and a cyano group (preferably one or two, more preferably one), and an ethylenically unsaturated carboxylic acid. The acid ester component means a monomer-derived component having a carbon-carbon double bond (preferably one) and a carboxylic acid ester site (esterified carboxy group) (preferably one), and vinyl fluoride A monomer component means an ethylene-derived component having 1 to 4 (preferably 2) fluorine atoms.
The "carbon-carbon double bond" above does not include the carbon-carbon double bond of the aromatic ring.
　共役ジエン成分を導く共役ジエンとしては、例えば、１，３－ブタジエン、２－メチル－１，３－ブタジエン（イソプレン）、２，３－ジメチル－１，３－ブタジエン及び２－クロロ－１，３－ブタジエン等の脂肪族共役ジエンが挙げられる。
　芳香族ビニルモノマー成分を導く芳香族ビニルモノマーとしては、例えば、スチレン、α－メチルスチレン、４－ｔｅｒｔ－ブチルスチレン、４－ｔｅｒｔ－ブトキシスチレン、ビニルトルエン（３－ビニルトルエン、４－ビニルトルエン）及びジビニルベンゼン（ｍ－ジビニルベンゼン、ｐ－ジビニルベンゼン）が挙げられる。
　エチレン性不飽和カルボン酸成分を導くエチレン性不飽和カルボン酸としては、例えば、（メタ）アクリル酸、マレイン酸、イタコン酸及びフマル酸が挙げられる。
　シアノ基含有エチレン性モノマー成分を導くシアノ基含有エチレン性モノマーとしては、例えば、（メタ）アクリロニトリル、α－クロロアクリロニトリル、α－エチルアクリロニトリル及びシアン化ビニリデンが挙げられる。
　エチレン性不飽和カルボン酸エステル成分を導くエチレン性不飽和カルボン酸エステルとしては、例えば、（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸プロピル、（メタ）アクリル酸ブチル、（メタ）アクリル酸ヘキシル、（メタ）アクリル酸オクチル及び２－エチルヘキシル（メタ）アクリレート等の（メタ）アクリル酸アルキルエステルが挙げられる。
　フッ化ビニルモノマー成分を導くフッ化ビニルモノマーとしては、例えば、フッ化ビニリデンが挙げられる。 Conjugated dienes leading to the conjugated diene component include, for example, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene and 2-chloro-1,3 - Aliphatic conjugated dienes such as butadiene.
Examples of aromatic vinyl monomers leading to aromatic vinyl monomer components include styrene, α-methylstyrene, 4-tert-butylstyrene, 4-tert-butoxystyrene, vinyltoluene (3-vinyltoluene, 4-vinyltoluene). and divinylbenzene (m-divinylbenzene, p-divinylbenzene).
Ethylenically unsaturated carboxylic acids leading to the ethylenically unsaturated carboxylic acid component include, for example, (meth)acrylic acid, maleic acid, itaconic acid and fumaric acid.
Examples of the cyano group-containing ethylenic monomer leading to the cyano group-containing ethylenic monomer component include (meth)acrylonitrile, α-chloroacrylonitrile, α-ethylacrylonitrile and vinylidene cyanide.
Examples of the ethylenically unsaturated carboxylic acid ester leading to the ethylenically unsaturated carboxylic acid ester component include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, Examples include (meth)acrylic acid alkyl esters such as hexyl (meth)acrylate, octyl (meth)acrylate and 2-ethylhexyl (meth)acrylate.
Examples of the vinyl fluoride monomer that leads to the vinyl fluoride monomer component include vinylidene fluoride.
　本発明に用いられる重合体粒子は、通常のポリマーの合成方法により得ることができる。本発明に用いられる重合体粒子の合成において、連鎖重合等の方法及び条件は、特に限定されず、通常の方法及び条件を、目的に応じて適宜に適用することができる。
　また、重合体粒子は、上述の逐次重合ポリマー粒子及び連鎖重合ポリマー粒子について、カルボキシ変性等の変性処理を行った粒子でもよい。変性処理の方法及び条件は、特に限定されず、常法により行うことができる。
　重合体粒子の水に対する溶解度、引張弾性率、ガラス転移温度及び平均粒径は、例えば、ポリマー中の構成成分の種類及び含有量により調整できる。 The polymer particles used in the present invention can be obtained by a conventional polymer synthesis method. In synthesizing the polymer particles used in the present invention, the method and conditions for chain polymerization and the like are not particularly limited, and ordinary methods and conditions can be appropriately applied depending on the purpose.
Further, the polymer particles may be particles obtained by subjecting the above-described successively polymerized polymer particles and chain polymerized polymer particles to modification treatment such as carboxy modification. The method and conditions for modification treatment are not particularly limited, and conventional methods can be used.
The solubility in water, tensile modulus, glass transition temperature and average particle size of the polymer particles can be adjusted by, for example, the types and contents of constituents in the polymer.
　重合体粒子の具体例としては、スチレン／ブタジエンコポリマー、アクリルポリマー及びポリ（フッ化ビニリデン）が挙げられ、スチレン／ブタジエンコポリマーが好ましい。
　スチレン／ブタジエンコポリマーとは、上記芳香族ビニルモノマー成分及び上記共役ジエン成分を有する共重合体を意味し、カルボキシ変性等の変性共重合体であってもよい。
　本発明において、重合体粒子は１種単独で用いてもよく、２種以上を組み合わせて用いてもよい。 Specific examples of polymeric particles include styrene/butadiene copolymers, acrylic polymers and poly(vinylidene fluoride), with styrene/butadiene copolymers being preferred.
A styrene/butadiene copolymer means a copolymer having the above aromatic vinyl monomer component and the above conjugated diene component, and may be a modified copolymer such as a carboxy-modified copolymer.
In the present invention, polymer particles may be used singly or in combination of two or more.
　本発明のバインダー組成物は、水溶性高分子（Ｘ）、水溶性高分子（Ｙ）及び重合体粒子以外に、電池用のバインダーとして常用されるその他のポリマーを含有していてもよい。
　本発明のバインダー組成物に含有される全てのポリマーに占める水溶性高分子（Ｘ）、水溶性高分子（Ｙ）及び重合体粒子の割合は、合計で８０質量％以上が好ましく、９０質量％以上がより好ましく、９５質量％以上が更に好ましく、９９質量％以上が特に好ましい。また、本発明のバインダー組成物に含有されるポリマーの全てが水溶性高分子（Ｘ）、水溶性高分子（Ｙ）及び重合体粒子であることが最も好ましい。
　本発明のバインダー組成物中、水溶性高分子（Ｘ）と、水溶性高分子（Ｙ）と、重合体粒子との質量比（水溶性高分子（Ｘ）の質量：水溶性高分子（Ｙ）の質量：重合体粒子の質量）は特に制限されず、１０～８０：１０～８０：１０～５０が好ましく、２０～７０：２０～７０：１０～３０がより好ましい。 In addition to the water-soluble polymer (X), water-soluble polymer (Y), and polymer particles, the binder composition of the present invention may contain other polymers commonly used as binders for batteries.
The total proportion of the water-soluble polymer (X), water-soluble polymer (Y) and polymer particles in all polymers contained in the binder composition of the present invention is preferably 80% by mass or more, and 90% by mass. The above is more preferable, 95% by mass or more is still more preferable, and 99% by mass or more is particularly preferable. Most preferably, all of the polymers contained in the binder composition of the present invention are water-soluble polymer (X), water-soluble polymer (Y) and polymer particles.
In the binder composition of the present invention, the mass ratio of the water-soluble polymer (X), the water-soluble polymer (Y), and the polymer particles (mass of the water-soluble polymer (X): water-soluble polymer (Y ):mass of polymer particles) is not particularly limited, and is preferably 10-80:10-80:10-50, more preferably 20-70:20-70:10-30.
　本発明のバインダー組成物は、液媒体として水を含有することが好ましい。
　本発明のバインダー組成物中の水の含有量は、特に制限されず、例えば、１０質量％以上とすることができ、好ましくは２０質量％以上、より好ましくは３０質量％以上、更に好ましくは４０質量％以上、特に好ましくは５０質量％以上である。本発明のバインダー組成物は、水を６０質量％以上含有していてもよく、７０質量％以上含有していてもよく、８０質量％以上含有していてもよい。一方、本発明のバインダー組成物中の水の含有量は、９９．５質量％以下であることが実際的である。
　本発明のバインダー組成物は、水以外の液媒体を含有していてもよい。水以外の液媒体としては、例えば、水と混合したときに相分離せずに混じり合う有機溶媒（以下、水溶性有機溶媒と称す。）が挙げられ、Ｎ－メチルピロリドン、メタノール、エタノール、アセトン、テトラヒドロフラン等が好ましく挙げられる。 The binder composition of the present invention preferably contains water as a liquid medium.
The content of water in the binder composition of the present invention is not particularly limited, and can be, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, and still more preferably 40% by mass. It is at least 50% by mass, particularly preferably at least 50% by mass. The binder composition of the present invention may contain water in an amount of 60% by mass or more, 70% by mass or more, or 80% by mass or more. On the other hand, it is practical that the water content in the binder composition of the present invention is 99.5% by mass or less.
The binder composition of the present invention may contain a liquid medium other than water. Liquid media other than water include, for example, organic solvents that mix with water without phase separation (hereinafter referred to as water-soluble organic solvents), such as N-methylpyrrolidone, methanol, ethanol, and acetone. , tetrahydrofuran and the like are preferred.
　本発明のバインダー組成物中、水溶性高分子（Ｘ）、水溶性高分子（Ｙ）及び重合体粒子の含有量は目的に応じて適宜に設定すればよい。例えば、バインダー組成物中の水溶性高分子（Ｘ）、水溶性高分子（Ｙ）及び重合体粒子の含有量を合計で０．５～５０質量％とすることができ、好ましくは５～３０質量％、より好ましくは１０～２０質量％である。
　本発明のバインダー組成物は、水溶性高分子（Ｘ）、水溶性高分子（Ｙ）、重合体粒子、水、水以外の液媒体の他にも、目的に応じて他の成分を含有することができる。他の成分としては、例えば、多価アルコール（ヒドロキシ基を２つ以上有するアルコール）が挙げられる。
　また、本発明のバインダー組成物は、水溶性高分子（Ｘ）、水溶性高分子（Ｙ）及び重合体粒子の合成液を希釈する等により調製することもできる。そのため、本発明のバインダー組成物中には、水溶性高分子（Ｘ）、水溶性高分子（Ｙ）及び重合体粒子の合成に使用した化合物又はその反応後の副生成物が含まれていてもよい。 The contents of the water-soluble polymer (X), the water-soluble polymer (Y) and the polymer particles in the binder composition of the present invention may be appropriately set according to the purpose. For example, the total content of the water-soluble polymer (X), water-soluble polymer (Y) and polymer particles in the binder composition can be 0.5 to 50% by mass, preferably 5 to 30%. % by mass, more preferably 10 to 20% by mass.
The binder composition of the present invention contains water-soluble polymer (X), water-soluble polymer (Y), polymer particles, water, liquid media other than water, and other components depending on the purpose. be able to. Other components include, for example, polyhydric alcohols (alcohols having two or more hydroxy groups).
The binder composition of the present invention can also be prepared by diluting a synthetic solution of the water-soluble polymer (X), water-soluble polymer (Y) and polymer particles. Therefore, the binder composition of the present invention contains the water-soluble polymer (X), the water-soluble polymer (Y), and the compounds used in the synthesis of the polymer particles or by-products after the reaction thereof. good too.
＜電極用組成物＞
　本発明のバインダー組成物は、その一形態として、水溶性高分子（Ｘ）、水溶性高分子（Ｙ）及び重合体粒子に加え、周期律表第１族又は第２族に属する金属のイオンの挿入放出が可能な活物質を含有しうる。本発明のバインダー組成物中に活物質を含有する場合を、特に本発明の電極用組成物と称す。本発明の電極用組成物は、必要に応じて更に導電助剤、他の添加剤を含むことができる。活物質は正極活物質でもよく、負極活物質でもよい。電極用組成物が正極活物質を含む場合、電極用組成物を、二次電池の正極活物質層形成用スラリーとして用いることができる。また、電極用組成物が負極活物質を含む場合、電極用組成物を負極活物質層形成用スラリーとして用いることができる。上記二次電池用バインダー組成物は正極又は負極どちらの電極用組成物にも適用できるが、負極に用いることが好ましく、特にケイ素系活物質を含有する負極の電極用組成物に用いることが好ましい。
　上記活物質、導電助剤、他の添加剤としては、特に限定されるものではなく、二次電池に常用されるものから目的に応じて適宜選択して用いればよい。 <Electrode composition>
The binder composition of the present invention, as one form thereof, contains the water-soluble polymer (X), the water-soluble polymer (Y) and polymer particles, and in addition, ions of metals belonging to Group 1 or Group 2 of the periodic table. can contain an active material capable of intercalating and releasing The case where the binder composition of the present invention contains an active material is particularly referred to as the electrode composition of the present invention. The electrode composition of the present invention may further contain a conductive aid and other additives as required. The active material may be a positive electrode active material or a negative electrode active material. When the electrode composition contains a positive electrode active material, the electrode composition can be used as slurry for forming a positive electrode active material layer of a secondary battery. Moreover, when the composition for electrodes contains a negative electrode active material, the composition for electrodes can be used as slurry for forming a negative electrode active material layer. The secondary battery binder composition can be applied to either a positive electrode or a negative electrode composition, but it is preferably used for a negative electrode, and particularly preferably used for a negative electrode composition containing a silicon-based active material. .
The active material, conductive aid, and other additives are not particularly limited, and may be appropriately selected and used from those commonly used in secondary batteries according to the purpose.
　水溶性高分子（Ｘ）、水溶性高分子（Ｙ）及び重合体粒子の、本発明の電極用組成物中の含有量は特に制限されず、全固形分量に対して、合計で０．５～３０質量％が好ましく、１．０～２０質量％がより好ましく、１．５～１５質量％が更に好ましく、２．５～１０質量％が特に好ましい。
　本発明の電極用組成物中、水溶性高分子（Ｘ）と、水溶性高分子（Ｙ）と、重合体粒子との質量比（水溶性高分子（Ｘ）の質量：水溶性高分子（Ｙ）の質量：重合体粒子の質量）は特に制限されず、１０～８０：１０～８０：１０～５０が好ましく、２０～７０：２０～７０：１０～３０がより好ましい。 The content of the water-soluble polymer (X), the water-soluble polymer (Y) and the polymer particles in the electrode composition of the present invention is not particularly limited, and is 0.5 in total with respect to the total solid content. ~30% by mass is preferred, 1.0 to 20% by mass is more preferred, 1.5 to 15% by mass is even more preferred, and 2.5 to 10% by mass is particularly preferred.
In the electrode composition of the present invention, the mass ratio of the water-soluble polymer (X), the water-soluble polymer (Y), and the polymer particles (mass of the water-soluble polymer (X): water-soluble polymer ( The mass of Y): mass of polymer particles) is not particularly limited, and is preferably 10-80:10-80:10-50, more preferably 20-70:20-70:10-30.
（正極活物質）
　正極活物質は、周期律表第１族又は第２族に属する金属のイオンの挿入放出が可能な活物質であればよく、中でも可逆的にリチウムイオンを挿入及び放出できるものが好ましい。その材料は、上記特性を有するものであれば、特に制限はなく、遷移金属酸化物、有機物、硫黄等のＬｉと複合化できる元素、硫黄と金属の複合物等でもよい。
　中でも、正極活物質としては、遷移金属酸化物を用いることが好ましく、遷移金属元素Ｍａ（Ｃｏ、Ｎｉ、Ｆｅ、Ｍｎ、Ｃｕ及びＶから選択される１種以上の元素）を有する遷移金属酸化物がより好ましい。また、この遷移金属酸化物に元素Ｍｂ（リチウム以外の周期律表の第１（Ｉａ）族の元素、第２（ＩＩａ）族の元素、Ａｌ、Ｇａ、Ｉｎ、Ｇｅ、Ｓｎ、Ｐｂ、Ｓｂ、Ｂｉ、Ｓｉ、Ｐ又はＢ等の元素）を混合してもよい。元素Ｍｂの混合量としては、遷移金属元素Ｍａの量１００モル％に対して０～３０モル％が好ましい。遷移金属元素Ｍａに対するＬｉのモル比（Ｌｉ／Ｍａ）が０．３～２．２になるように混合して合成されたものが、より好ましい。
　遷移金属酸化物の具体例としては、（ＭＡ）層状岩塩型構造を有する遷移金属酸化物、（ＭＢ）スピネル型構造を有する遷移金属酸化物、（ＭＣ）リチウム含有遷移金属リン酸化合物、（ＭＤ）リチウム含有遷移金属ハロゲン化リン酸化合物及び（ＭＥ）リチウム含有遷移金属ケイ酸化合物等が挙げられる。 (Positive electrode active material)
The positive electrode active material may be any active material capable of inserting and releasing ions of metals belonging to Group 1 or Group 2 of the periodic table, and among these, those capable of reversibly inserting and releasing lithium ions are preferable. The material is not particularly limited as long as it has the above properties, and may be a transition metal oxide, an organic substance, an element such as sulfur that can be combined with Li, a compound of sulfur and a metal, or the like.
Among them, it is preferable to use a transition metal oxide as the positive electrode active material. objects are more preferred. In addition, the element M b (an element of group 1 (Ia) of the periodic table other than lithium, an element of group 2 (IIa) of the periodic table, Al, Ga, In, Ge, Sn, Pb, Sb) is added to the transition metal oxide. , Bi, Si, P or B) may be mixed. The mixing amount of the element Mb is preferably 0 to 30 mol % with respect to 100 mol % of the transition metal element M a . It is more preferable to synthesize by mixing so that the molar ratio of Li to the transition metal element M a (Li/M a ) is 0.3 to 2.2.
Specific examples of the transition metal oxide include (MA) a transition metal oxide having a layered rock salt structure, (MB) a transition metal oxide having a spinel structure, (MC) a lithium-containing transition metal phosphate compound, (MD ) lithium-containing transition metal halide phosphate compounds and (ME) lithium-containing transition metal silicate compounds.
　（ＭＡ）層状岩塩型構造を有する遷移金属酸化物の具体例として、ＬｉＣｏＯ２（コバルト酸リチウム［ＬＣＯ］）、ＬｉＮｉ２Ｏ２（ニッケル酸リチウム）、ＬｉＮｉ０．８５Ｃｏ０．１０Ａｌ０．０５Ｏ２（ニッケルコバルトアルミニウム酸リチウム［ＮＣＡ］）、ＬｉＮｉ１／３Ｃｏ１／３Ｍｎ１／３Ｏ２（ニッケルマンガンコバルト酸リチウム［ＮＭＣ］）及びＬｉＮｉ０．５Ｍｎ０．５Ｏ２（マンガンニッケル酸リチウム）が挙げられる。
　（ＭＢ）スピネル型構造を有する遷移金属酸化物の具体例として、ＬｉＭｎ２Ｏ４（ＬＭＯ）、ＬｉＣｏＭｎＯ４、Ｌｉ２ＦｅＭｎ３Ｏ８、Ｌｉ２ＣｕＭｎ３Ｏ８、Ｌｉ２ＣｒＭｎ３Ｏ８及びＬｉ２ＮｉＭｎ３Ｏ８が挙げられる。
　（ＭＣ）リチウム含有遷移金属リン酸化合物としては、例えば、ＬｉＦｅＰＯ４及びＬｉ３Ｆｅ２（ＰＯ４）３等のオリビン型リン酸鉄塩、ＬｉＦｅＰ２Ｏ７等のピロリン酸鉄類、ＬｉＣｏＰＯ４等のリン酸コバルト類並びにＬｉ３Ｖ２（ＰＯ４）３（リン酸バナジウムリチウム）等の単斜晶ナシコン型リン酸バナジウム塩が挙げられる。
　（ＭＤ）リチウム含有遷移金属ハロゲン化リン酸化合物としては、例えば、Ｌｉ２ＦｅＰＯ４Ｆ等のフッ化リン酸鉄塩、Ｌｉ２ＭｎＰＯ４Ｆ等のフッ化リン酸マンガン塩及びＬｉ２ＣｏＰＯ４Ｆ等のフッ化リン酸コバルト類が挙げられる。
　（ＭＥ）リチウム含有遷移金属ケイ酸化合物としては、例えば、Ｌｉ２ＦｅＳｉＯ４、Ｌｉ２ＭｎＳｉＯ４及びＬｉ２ＣｏＳｉＯ４等が挙げられる。
　本発明では、（ＭＡ）層状岩塩型構造を有する遷移金属酸化物が好ましく、ＬＣＯ又はＮＭＣがより好ましい。 (MA) Specific examples of transition metal oxides having a layered rocksalt structure include LiCoO 2 (lithium cobalt oxide [LCO]), LiNi 2 O 2 (lithium nickel oxide), and LiNi 0.85 Co 0.10 Al 0.85. 05O2 (lithium nickel cobalt aluminum oxide [NCA]), LiNi1 /3Co1/ 3Mn1 / 3O2 ( lithium nickel manganese cobaltate [NMC]) and LiNi0.5Mn0.5O2 ( lithium manganese nickelate).
(MB) Specific examples of transition metal oxides having a spinel structure include LiMn 2 O 4 (LMO), LiCoMnO 4 , Li 2 FeMn 3 O 8 , Li 2 CuMn 3 O 8 , Li 2 CrMn 3 O 8 and Li 2NiMn3O8 . _
Examples of (MC) lithium-containing transition metal phosphate compounds include olivine-type iron phosphates such as LiFePO 4 and Li 3 Fe 2 (PO 4 ) 3 , iron pyrophosphates such as LiFeP 2 O 7 , and LiCoPO 4 . and monoclinic Nasicon-type vanadium phosphates such as Li 3 V 2 (PO 4 ) 3 (lithium vanadium phosphate).
Examples of (MD) lithium-containing transition metal halogenated phosphate compounds include iron fluorophosphates such as Li 2 FePO 4 F, manganese fluorophosphates such as Li 2 MnPO 4 F, and Li 2 CoPO 4 F. and other cobalt fluoride phosphates.
(ME) Lithium-containing transition metal silicate compounds include, for example, Li 2 FeSiO 4 , Li 2 MnSiO 4 and Li 2 CoSiO 4 .
In the present invention, transition metal oxides having a (MA) layered rocksalt structure are preferred, and LCO or NMC is more preferred.
　正極活物質の形状は特に制限されず、粒子状が好ましい。正極活物質の平均粒径（体積基準のメジアン径Ｄ５０）は特に制限されない。例えば、０．１～５０μｍとすることができる。正極活物質を所定の粒子径にするには、粉砕機又は分級機を用い常法により調製すればよい。後述する負極活物質の所定の粒子径への調製方法も適用することができる。焼成法によって得られた正極活物質は、水、酸性水溶液、アルカリ性水溶液又は有機溶剤等にて洗浄した後使用してもよい。
　市販品の正極活物質を用いる場合、正極活物質の平均粒径は製造元のカタログ記載の値を採用し、製造元の平均粒径の情報が入手できない場合又は合成した正極活物質を用いる場合は、後述の負極活物質に記載の方法により測定、算出された値を採用する。 The shape of the positive electrode active material is not particularly limited, and is preferably particulate. The average particle diameter (volume-based median diameter D50) of the positive electrode active material is not particularly limited. For example, it can be 0.1 to 50 μm. In order to make the positive electrode active material have a predetermined particle size, it may be prepared by a conventional method using a pulverizer or a classifier. A method for preparing a negative electrode active material having a predetermined particle size, which will be described later, can also be applied. The positive electrode active material obtained by the calcination method may be washed with water, an acidic aqueous solution, an alkaline aqueous solution, an organic solvent, or the like before use.
When using a commercially available positive electrode active material, adopt the value described in the manufacturer's catalog for the average particle size of the positive electrode active material. A value measured and calculated by the method described below for the negative electrode active material is employed.
　上記焼成法により得られた化合物の化学式は、測定方法として誘導結合プラズマ（ＩＣＰ）発光分光分析法、簡便法として、焼成前後の粉体の質量差から算出できる。 The chemical formula of the compound obtained by the above firing method can be calculated by inductively coupled plasma (ICP) emission spectrometry as a measurement method and from the difference in mass of the powder before and after firing as a simple method.
　正極活物質の表面は、別の金属酸化物等の酸化物、炭素系材料等で表面被覆されていてもよい。表面被覆材としては、後述する負極活物質の表面被覆に用いうる表面被覆材を用いることができる。 The surface of the positive electrode active material may be surface-coated with an oxide such as another metal oxide, a carbon-based material, or the like. As the surface coating material, a surface coating material that can be used for coating the surface of the negative electrode active material described later can be used.
　また、正極活物質の表面は硫黄又はリンで表面処理されていてもよい。
　更に、正極活物質の粒子表面は、上記表面被覆の前後において活性光線又は活性気体（プラズマ等）により表面処理を施されていてもよい。 Moreover, the surface of the positive electrode active material may be surface-treated with sulfur or phosphorus.
Furthermore, the particle surface of the positive electrode active material may be surface-treated with actinic rays or an active gas (plasma, etc.) before and after the surface coating.
　上記正極活物質は、１種を単独で用いても、２種以上を組み合わせて用いてもよい。
　正極活物質層を形成する場合、正極活物質層の単位面積（ｃｍ２）当たりの正極活物質の質量（ｍｇ）（目付量）は特に限定されるものではない。設計された電池容量に応じて、適宜に決めることができる。 The said positive electrode active material may be used individually by 1 type, or may be used in combination of 2 or more type.
When the positive electrode active material layer is formed, the mass (mg) (basis weight) of the positive electrode active material per unit area (cm 2 ) of the positive electrode active material layer is not particularly limited. It can be determined appropriately according to the designed battery capacity.
　本発明の電極用組成物中における正極活物質の含有量は、特に限定されず、全固形分量に対して、１０～９９質量％が好ましく、３０～９８質量％がより好ましく、５０～９７質量％が更に好ましく、５５～９５質量％が特に好ましい。 The content of the positive electrode active material in the electrode composition of the present invention is not particularly limited, and is preferably 10 to 99% by mass, more preferably 30 to 98% by mass, more preferably 50 to 97% by mass, based on the total solid content. % is more preferred, and 55 to 95% by mass is particularly preferred.
（負極活物質）
　負極活物質は、周期律表第１族又は第２族に属する金属のイオン（好ましくはリチウムイオン）の挿入放出が可能な活物質であればよく、中でも可逆的にリチウムイオンを吸蔵及び放出できるものが好ましい。その材料は、上記特性を有するものであれば、特に制限はなく、炭素質材料、ケイ素系材料（ケイ素元素を含有する材料を意味する。）、スズ系材料（スズ元素を含有する材料を意味する。）、金属酸化物、金属複合酸化物、リチウム単体、リチウム合金等が挙げられる。中でも、炭素質材料又はケイ素系材料が信頼性の点から好ましく用いられる。 (Negative electrode active material)
The negative electrode active material may be an active material capable of inserting and releasing metal ions (preferably lithium ions) belonging to Group 1 or Group 2 of the periodic table, and in particular, capable of reversibly intercalating and deintercalating lithium ions. things are preferred. The material is not particularly limited as long as it has the above properties. Carbonaceous materials, silicon-based materials (meaning materials containing silicon element), tin-based materials (meaning materials containing tin element) ), metal oxides, metal composite oxides, elemental lithium, lithium alloys, and the like. Among them, a carbonaceous material or a silicon-based material is preferably used from the viewpoint of reliability.
　負極活物質として用いられる炭素質材料とは、実質的に炭素からなる材料である。例えば、石油ピッチ、アセチレンブラック等のカーボンブラック、黒鉛（鱗片状黒鉛、塊状黒鉛等の天然黒鉛、気相成長黒鉛、繊維状黒鉛等の人造黒鉛、鱗片状黒鉛を特殊加工してなる膨張黒鉛等）、活性炭、カーボンファイバー、コークス、ソフトカーボン、ハードカーボン、及びＰＡＮ（ポリアクリロニトリル）系の樹脂若しくはフルフリルアルコール樹脂等の各種の合成樹脂を焼成した炭素質材料を挙げることができる。更に、ＰＡＮ系炭素繊維、セルロース系炭素繊維、ピッチ系炭素繊維、気相成長炭素繊維、脱水ＰＶＡ（ポリビニルアルコール）系炭素繊維、リグニン炭素繊維、ガラス状炭素繊維及び活性炭素繊維等の各種炭素繊維類、メソフェーズ微小球体、グラファイトウィスカー並びに平板状の黒鉛等を挙げることもできる。 A carbonaceous material used as a negative electrode active material is a material that is substantially made of carbon. For example, petroleum pitch, carbon black such as acetylene black, graphite (natural graphite such as flaky graphite and massive graphite, artificial graphite such as vapor-grown graphite and fibrous graphite, expanded graphite obtained by special processing of flaky graphite, etc. ), activated carbon, carbon fiber, coke, soft carbon, hard carbon, and carbonaceous materials obtained by baking various synthetic resins such as PAN (polyacrylonitrile)-based resins and furfuryl alcohol resins. Furthermore, various carbon fibers such as PAN-based carbon fiber, cellulose-based carbon fiber, pitch-based carbon fiber, vapor growth carbon fiber, dehydrated PVA (polyvinyl alcohol)-based carbon fiber, lignin carbon fiber, vitreous carbon fiber and activated carbon fiber. , mesophase microspheres, graphite whiskers and tabular graphite.
　負極活物質として用いられるスズ系材料（スズ系活物質）としては、例えば、Ｓｎ、ＳｎＯ、ＳｎＯ２、ＳｎＳ、ＳｎＳ２が挙げられる。 Tin-based materials (tin-based active materials) used as negative electrode active materials include, for example, Sn, SnO, SnO 2 , SnS, and SnS 2 .
　負極活物質として適用される金属酸化物及び金属複合酸化物としては、周期律表第１族又は第２族に属する金属のイオンの挿入放出が可能な酸化物であれば特に制限されず、金属酸化物としては金属元素の酸化物（金属酸化物）及び、半金属元素の酸化物（半金属酸化物）が挙げられ、金属複合酸化物としては、金属元素の複合酸化物、金属元素と半金属元素との複合酸化物、及び、半金属元素の複合酸化物が挙げられる。
　これらの金属酸化物及び金属複合酸化物としては、非晶質酸化物が好ましく、更に金属元素と周期律表第１６族の元素との反応生成物であるカルコゲナイドも好ましく挙げられる。ここでいう非晶質とは、ＣｕＫα線を用いたＸ線回折法で、２θ値で２０°～４０°の領域に頂点を有するブロードな散乱帯を有するものを意味し、結晶性の回折線を有してもよい。
　上記非晶質酸化物及びカルコゲナイドからなる化合物群の中でも、半金属元素の非晶質酸化物、又は上記カルコゲナイドがより好ましく、周期律表第１３（ＩＩＩＢ）族～１５（ＶＢ）族の元素（例えば、Ａｌ、Ｇａ、Ｓｉ、Ｓｎ、Ｇｅ、Ｐｂ、Ｓｂ及びＢｉ）のうちの１種単独若しくはそれらの２種以上の組み合わせからなる酸化物もしくは複合酸化物、又はカルコゲナイドが特に好ましい。非晶質酸化物及びカルコゲナイドの具体例としては、例えば、Ｇａ２Ｏ３、ＧｅＯ、ＰｂＯ、ＰｂＯ２、Ｐｂ２Ｏ３、Ｐｂ２Ｏ４、Ｐｂ３Ｏ４、Ｓｂ２Ｏ３、Ｓｂ２Ｏ４、Ｓｂ２Ｏ８Ｂｉ２Ｏ３、Ｓｂ２Ｏ８Ｓｉ２Ｏ３、Ｓｂ２Ｏ５、Ｂｉ２Ｏ３、Ｂｉ２Ｏ４、ＧｅＳ、ＰｂＳ、ＰｂＳ２、Ｓｂ２Ｓ３及びＳｂ２Ｓ５が好ましく挙げられる。 The metal oxide and metal composite oxide used as the negative electrode active material are not particularly limited as long as they are oxides capable of inserting and releasing ions of metals belonging to Group 1 or Group 2 of the periodic table. Examples of oxides include oxides of metal elements (metal oxides) and oxides of semimetal elements (semimetal oxides). Metal composite oxides include composite oxides of metal elements, Composite oxides with metal elements and composite oxides with metalloid elements are included.
As these metal oxides and metal composite oxides, amorphous oxides are preferred, and chalcogenides, which are reaction products of metal elements and Group 16 elements of the periodic table, are also preferred. The term “amorphous” as used herein means a broad scattering band having an apex in the region of 20° to 40° in terms of 2θ value in an X-ray diffraction method using CuKα rays, and a crystalline diffraction line. may have
Among the compound group consisting of the above amorphous oxides and chalcogenides, amorphous oxides of metalloid elements or the above chalcogenides are more preferable, and elements of groups 13 (IIIB) to 15 (VB) of the periodic table ( For example, oxides or composite oxides, or chalcogenides consisting of one of Al, Ga, Si, Sn, Ge, Pb, Sb and Bi) alone or in combination of two or more thereof are particularly preferable. Specific examples of amorphous oxides and chalcogenides include Ga2O3 , GeO, PbO, PbO2 , Pb2O3 , Pb2O4 , Pb3O4 , Sb2O3 , Sb2O 4 , Sb2O8Bi2O3 , Sb2O8Si2O3 , Sb2O5 , Bi2O3 , Bi2O4 , GeS , PbS , PbS2 , Sb2S3 and Sb2S 5 is preferred.
　金属（複合）酸化物及び上記カルコゲナイドは、構成成分として、チタン及びリチウムの少なくとも一方を含有していることが、高電流密度充放電特性の観点で好ましい。リチウムを含有する金属複合酸化物（リチウム複合金属酸化物）としては、例えば、酸化リチウムと上記金属（複合）酸化物若しくは上記カルコゲナイドとの複合酸化物、より具体的には、Ｌｉ２ＳｎＯ２が挙げられる。 The metal (composite) oxide and the chalcogenide preferably contain at least one of titanium and lithium as a constituent component from the viewpoint of high current density charge/discharge characteristics. Examples of lithium-containing metal composite oxides (lithium composite metal oxides) include composite oxides of lithium oxide and the above metal (composite) oxides or chalcogenides, more specifically Li 2 SnO 2 . mentioned.
　負極活物質はチタン元素を含有することも好ましい。より具体的にはＴｉＮｂ２Ｏ７（チタン酸ニオブ酸化物［ＮＴＯ］）、Ｌｉ４Ｔｉ５Ｏ１２（チタン酸リチウム［ＬＴＯ］）がリチウムイオンの吸蔵放出時の体積変動が小さいことから急速充放電特性に優れ、電極の劣化が抑制され、リチウムイオン二次電池のサイクル特性向上が可能となる点で好ましい。 It is also preferable that the negative electrode active material contains a titanium element. More specifically, TiNb 2 O 7 (niobium titanate [NTO]) and Li 4 Ti 5 O 12 (lithium titanate [LTO]) have small volume fluctuations when absorbing and desorbing lithium ions, and are therefore suitable for rapid charging. It is preferable in that the discharge characteristics are excellent, the deterioration of the electrode is suppressed, and the cycle characteristics of the lithium ion secondary battery can be improved.
　負極活物質としてのリチウム合金としては、二次電池の負極活物質として通常用いられる合金であれば特に制限されず、例えば、リチウムアルミニウム合金が挙げられる。 The lithium alloy as the negative electrode active material is not particularly limited as long as it is an alloy normally used as a negative electrode active material for secondary batteries, and examples thereof include lithium aluminum alloys.
　ケイ素系材料（ケイ素系活物質）としては、ケイ素元素を含む負極活物質であり、例えば、Ｓｉ、ＳｉＯｘ（０＜ｘ≦１．５）等のケイ素材料、更には、チタン、バナジウム、クロム、マンガン、ニッケル、銅若しくはランタンを含むケイ素含有合金（例えば、ＬａＳｉ２、ＶＳｉ２）、又は組織化した活物質（例えば、ＬａＳｉ２／Ｓｉ）、他にも、上述の金属酸化物及び金属複合酸化物の記載におけるケイ素元素を含む酸化物又は複合酸化物、ＳｎＳｉＯ３、ＳｎＳｉＳ３等のケイ素元素及びスズ元素を含む活物質等が挙げられる。
　ＳｉＯｘは、それ自体を負極活物質（半金属酸化物）として用いることができ、また、電池の稼働によりＳｉを生成するため、リチウムと合金形成可能な活物質（その前駆体物質）として用いることができる。 The silicon - based material (silicon-based active material) is a negative electrode active material containing a silicon element. , manganese, nickel, copper or lanthanum containing silicon-containing alloys (e.g. LaSi2 , VSi2 ), or structured active materials (e.g. LaSi2 /Si), as well as the metal oxides and metal composites mentioned above. Examples include oxides or composite oxides containing silicon element in the description of oxides, and active materials containing silicon element and tin element such as SnSiO 3 and SnSiS 3 .
SiO x itself can be used as a negative electrode active material (semimetal oxide), and since Si is generated by the operation of the battery, it is used as an active material (precursor material thereof) capable of forming an alloy with lithium. be able to.
　上記では負極活物質を成分に着目して説明しているが、特性の観点からは、負極活物質は、リチウムと合金形成可能な負極活物質であることが好ましい。
　リチウムと合金形成可能な負極活物質は、二次電池の負極活物質として通常用いられるものであれば特に制限されない。このような活物質として、上述のケイ素元素及び／又はスズ元素を含む負極活物質、Ａｌ及びＩｎ等の各金属が挙げられる。より高い電池容量を可能とする点でケイ素系活物質が好ましく、ケイ素元素の含有量が全構成元素の４０モル％以上であるケイ素系活物質がより好ましい。
　一般的に、これらのリチウムと合金形成可能な負極活物質を含有する負極（例えば、ケイ素系活物質を含むＳｉ負極、スズ系活物質を含むＳｎ負極）は、炭素質材料のみからなる負極（黒鉛、カーボンブラック等）に比べて、より多くのＬｉイオンを吸蔵できる。すなわち、単位質量あたりのＬｉイオンの吸蔵量が増加する。そのため、電池容量（エネルギー密度）を大きくすることができる。その結果、バッテリー駆動時間を長くすることができるという利点がある。このように、ケイ素元素及び／又はスズ元素を含む負極活物質は、高容量活物質とも称される。 Although the negative electrode active material has been described above by focusing on its components, from the viewpoint of characteristics, the negative electrode active material is preferably a negative electrode active material capable of forming an alloy with lithium.
The negative electrode active material capable of forming an alloy with lithium is not particularly limited as long as it is commonly used as a negative electrode active material for secondary batteries. Examples of such an active material include the aforementioned negative electrode active material containing silicon element and/or tin element, and metals such as Al and In. A silicon-based active material is preferable in terms of enabling a higher battery capacity, and a silicon-based active material containing 40 mol % or more of the total constituent elements is more preferable.
In general, a negative electrode containing a negative electrode active material capable of forming an alloy with lithium (for example, a Si negative electrode containing a silicon-based active material, a Sn negative electrode containing a tin-based active material) is a negative electrode made only of a carbonaceous material ( Graphite, carbon black, etc.) can occlude more Li ions. That is, the amount of Li ions stored per unit mass increases. Therefore, the battery capacity (energy density) can be increased. As a result, there is an advantage that the battery driving time can be lengthened. Thus, the negative electrode active material containing silicon element and/or tin element is also called high capacity active material.
　負極活物質の表面は、別の金属酸化物等の酸化物、炭素系材料等で表面被覆されていてもよい（以下、炭素系材料で表面被覆されていることを「カーボンコートされた」と記載することがある）。表面被覆材としてはＴｉ、Ｎｂ、Ｔａ、Ｗ、Ｚｒ、Ａｌ、Ｓｉ又はＬｉを含有する金属酸化物等が挙げられる。具体的には、チタン酸スピネル、タンタル系酸化物、ニオブ系酸化物、ニオブ酸リチウム系化合物等が挙げられ、更に具体的には、Ｌｉ４Ｔｉ５Ｏ１２、Ｌｉ２Ｔｉ２Ｏ５、ＬｉＴａＯ３、ＬｉＮｂＯ３、ＬｉＡｌＯ２、Ｌｉ２ＺｒＯ３、Ｌｉ２ＷＯ４、Ｌｉ２ＴｉＯ３、Ｌｉ２Ｂ４Ｏ７、Ｌｉ３ＰＯ４、Ｌｉ２ＭｏＯ４、Ｌｉ３ＢＯ３、ＬｉＢＯ２、Ｌｉ２ＣＯ３、Ｌｉ２ＳｉＯ３、ＳｉＯ２、ＴｉＯ２、ＺｒＯ２、Ａｌ２Ｏ３、Ｂ２Ｏ３等が挙げられる。また、Ｃ、ＳｉＣ、炭素添加シリコン酸化物等の炭素系材料も表面被覆材として用いることができる。 The surface of the negative electrode active material may be surface-coated with an oxide such as another metal oxide, a carbon-based material, or the like (hereinafter, surface-coated with a carbon-based material is referred to as “carbon-coated”. may be stated). Examples of the surface coating material include metal oxides containing Ti, Nb, Ta, W, Zr, Al, Si or Li. Specific examples include titanate spinel, tantalum-based oxides, niobium-based oxides, lithium niobate-based compounds, and more specifically Li 4 Ti 5 O 12 , Li 2 Ti 2 O 5 , LiTaO. 3 , LiNbO3 , LiAlO2 , Li2ZrO3 , Li2WO4 , Li2TiO3 , Li2B4O7 , Li3PO4 , Li2MoO4 , Li3BO3 , LiBO2 , Li2 CO 3 , Li 2 SiO 3 , SiO 2 , TiO 2 , ZrO 2 , Al 2 O 3 , B 2 O 3 and the like. Carbon-based materials such as C, SiC, and carbon-added silicon oxide can also be used as the surface coating material.
　また、負極活物質の表面は硫黄又はリンで表面処理されていてもよい。
　更に、負極活物質の粒子表面は、上記表面被覆の前後において活性光線又は活性気体（プラズマ等）により表面処理を施されていてもよい。 Moreover, the surface of the negative electrode active material may be surface-treated with sulfur or phosphorus.
Furthermore, the surface of the particles of the negative electrode active material may be surface-treated with actinic rays or an active gas (such as plasma) before and after the surface coating.
　負極活物質は、金属元素をドープされていてもよい。金属元素をドープされた負極活物質において、ドープされる金属元素は、Ｌｉ、Ｎｉ及びＴｉの少なくともいずれか１種であることが好ましく、Ｌｉであることがより好ましい。 The negative electrode active material may be doped with a metal element. In the negative electrode active material doped with a metal element, the doped metal element is preferably at least one of Li, Ni and Ti, more preferably Li.
　本発明においては、負極活物質として、ケイ素系活物質を用いることが好ましく、酸化ケイ素（ＳｉＯｘ（０＜ｘ≦１．５））又はカーボンコートされた酸化ケイ素（カーボンコートされたＳｉＯｘ（０＜ｘ≦１．５））を用いることがより好ましく、カーボンコートされた酸化ケイ素を用いることが更に好ましい。カーボンコートされた酸化ケイ素は、更に金属元素をドープされていてもよい。
　カーボンコートされた酸化ケイ素中に占める炭素元素の含有量の割合は特に制限されず、例えば、０．５～５質量％が好ましく、１～３質量％がより好ましい。
　酸化ケイ素又はカーボンコートされた酸化ケイ素は市販品を用いてもよい。また、カーボンコートされた酸化ケイ素は、例えば特開２０１９－２０４６８６号公報を参照して、酸化ケイ素をカーボンコートすることにより調製することもできる。
　負極活物質中の酸化ケイ素又はカーボンコートされた酸化ケイ素の含有量は特に制限されず、例えば１０～９０質量％とすることができ、１０～５０質量％が好ましく、１５～４０質量％がより好ましい。 In the present invention, it is preferable to use a silicon-based active material as the negative electrode active material, and silicon oxide (SiO x (0<x≦1.5)) or carbon-coated silicon oxide (carbon-coated SiO x ( 0<x≦1.5)), more preferably carbon-coated silicon oxide. The carbon-coated silicon oxide may be further doped with a metal element.
The ratio of the carbon element content in the carbon-coated silicon oxide is not particularly limited, and is preferably 0.5 to 5% by mass, more preferably 1 to 3% by mass.
Commercially available silicon oxide or carbon-coated silicon oxide may be used. Carbon-coated silicon oxide can also be prepared by carbon-coating silicon oxide, for example, with reference to JP-A-2019-204686.
The content of silicon oxide or carbon-coated silicon oxide in the negative electrode active material is not particularly limited, and can be, for example, 10 to 90% by mass, preferably 10 to 50% by mass, more preferably 15 to 40% by mass. preferable.
　本発明においては、負極活物質として、金属元素をドープされたケイ素系材料を用いることも好ましく、Ｌｉ、Ｎｉ及びＴｉの少なくともいずれか１種をドープされたケイ素系材料がより好ましく、Ｌｉをドープされたケイ素系材料が更に好ましい。金属元素のドープに付されるケイ素系材料としては、酸化ケイ素又はカーボンコートされた酸化ケイ素が好ましい。
　金属元素をドープされた酸化ケイ素、並びに、金属元素のドープ及びカーボンコートの両方が施された酸化ケイ素としては、市販品を用いてもよい。また、例えば、特開２０２２－１２１５８２号公報、国際公開第１４／１８８８５１号及び特開２０２１－１５００７７号公報等を参照して、酸化ケイ素又はカーボンコートされた酸化ケイ素に金属元素をドープすること、又は、酸化ケイ素に金属元素をドープし、必要に応じてさらにカーボンコートを施すことにより調製することもできる。
　本発明において、「金属元素のドープ及びカーボンコートの両方が施された」とは、金属元素のドープを施した後、カーボンコート処理を施したもの、及び、カーボンコート処理を施した後、金属元素のドープを施したものの両方を含む意味で使用する。
　本発明においては、負極活物質として、金属元素のドープ及びカーボンコートの両方が施されたケイ素系材料を用いることも好ましく、このような負極活物質としては、金属元素のドープ及びカーボンコートの両方が施された酸化ケイ素がより好ましく、リチウムドープ及びカーボンコートの両方が施された酸化ケイ素が特に好ましい。 In the present invention, a silicon-based material doped with a metal element is preferably used as the negative electrode active material, and a silicon-based material doped with at least one of Li, Ni and Ti is more preferable, and Li is doped. Further preferred are silicon-based materials. Silicon oxide or carbon-coated silicon oxide is preferable as the silicon-based material to be doped with a metal element.
As the silicon oxide doped with a metal element and the silicon oxide doped with both a metal element and a carbon coat, commercially available products may be used. Also, for example, referring to JP-A-2022-121582, WO 14/188851 and JP-A-2021-150077, doping a metal element into silicon oxide or carbon-coated silicon oxide, Alternatively, it can be prepared by doping silicon oxide with a metal element and, if necessary, further applying a carbon coat.
In the present invention, the phrase “both doped with a metal element and carbon-coated” means a product that has been doped with a metal element and then subjected to a carbon coating treatment, and a product that has been subjected to a carbon coating treatment and then subjected to a metal coating treatment. It is used in the sense of including both elements doped with an element.
In the present invention, it is also preferable to use a silicon-based material that is both doped with a metal element and coated with carbon as the negative electrode active material. is more preferred, and silicon oxide that is both lithium-doped and carbon-coated is particularly preferred.
　負極活物質の形状は特に制限されず、粒子状が好ましい。負極活物質の平均粒径（体積基準のメジアン径Ｄ５０）は、０．１～６０μｍが好ましい。更に、負極活物質が酸化ケイ素又はカーボンコートされた酸化ケイ素である場合、平均粒径は５～２０μｍがより好ましい。所定の粒子径にするには、粉砕機又は分級機を用い常法により調製することができる。例えば、乳鉢、ボールミル、サンドミル、振動ボールミル、衛星ボールミル、遊星ボールミル、旋回気流型ジェットミル又は篩等が好適に用いられる。粉砕時には水又はメタノール等の有機溶媒を共存させた湿式粉砕も行うことができる。所望の粒子径とするためには分級を行うことが好ましい。分級方法としては、特に限定はなく、篩、風力分級機等を所望により用いることができる。分級は乾式及び湿式ともに用いることができる。
　市販品の負極活物質を用いる場合、負極活物質の平均粒径は製造元のカタログ記載の値を採用する。
　製造元の平均粒径の情報が入手できない場合又は合成した負極活物質を用いる場合は、負極活物質を水中で分散させ、レーザ回折／散乱式粒子径分布測定装置（例えば、ＨＯＲＩＢＡ社製のＰａｒｔｉｃｌｅ　ＬＡ－９６０Ｖ２（商品名））で測定して得られる平均粒径の値（水中での体積基準のメジアン径Ｄ５０）を採用する。 The shape of the negative electrode active material is not particularly limited, and is preferably particulate. The average particle diameter (volume-based median diameter D50) of the negative electrode active material is preferably 0.1 to 60 μm. Furthermore, when the negative electrode active material is silicon oxide or carbon-coated silicon oxide, the average particle size is more preferably 5 to 20 μm. In order to obtain a predetermined particle size, it can be prepared by a conventional method using a pulverizer or a classifier. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a whirling jet mill, a sieve, or the like is preferably used. At the time of pulverization, wet pulverization can also be performed in which an organic solvent such as water or methanol is allowed to coexist. Classification is preferably carried out in order to obtain a desired particle size. The classification method is not particularly limited, and a sieve, an air classifier, or the like can be used as desired. Both dry and wet classification can be used.
When using a commercially available negative electrode active material, the average particle size of the negative electrode active material is the value described in the manufacturer's catalog.
If information on the average particle size of the manufacturer cannot be obtained or if a synthesized negative electrode active material is used, the negative electrode active material is dispersed in water and measured with a laser diffraction/scattering particle size distribution analyzer (for example, HORIBA's Particle LA -960V2 (trade name)) is used (volume-based median diameter D50 in water) obtained by measurement.
　負極活物質は、１種を単独で用いても、２種以上を組み合わせて用いてもよい。その中でも、ケイ素系活物質と炭素質材料との組み合わせが好ましく、ケイ素系活物質と黒鉛との組み合わせがより好ましく、酸化ケイ素又はカーボンコートされた酸化ケイ素と黒鉛との組み合わせが更に好ましい。酸化ケイ素及びカーボンコートされた酸化ケイ素は、それぞれ、上述の金属元素のドープが施された酸化ケイ素及び金属元素のドープ及びカーボンコートの両方が施された酸化ケイ素であってもよい。ドープされる金属元素は、Ｌｉ、Ｎｉ及びＴｉの少なくともいずれか１種であることが好ましく、Ｌｉであることがより好ましい。
　ケイ素系活物質と黒鉛とを組み合わせる場合、黒鉛に対するケイ素系活物質の質量比率（ケイ素系活物質／黒鉛）は２以下が好ましく、１以下がより好ましく、０．５以下が更に好ましい。黒鉛に対するケイ素系活物質の質量比率の下限値に特に制限はないが、０．０５以上が実際的である。
　負極活物質層を形成する場合、負極活物質層の単位面積（ｃｍ２）当たりの負極活物質の質量（ｍｇ）（目付量）は特に限定されるものではない。設計された電池容量に応じて、適宜に決めることができる。 A negative electrode active material may be used individually by 1 type, or may be used in combination of 2 or more type. Among them, a combination of a silicon-based active material and a carbonaceous material is preferable, a combination of a silicon-based active material and graphite is more preferable, and a combination of silicon oxide or carbon-coated silicon oxide and graphite is even more preferable. The silicon oxide and carbon-coated silicon oxide may be silicon oxide doped with a metal element and silicon oxide both doped with a metal element and carbon-coated, respectively, as described above. The metal element to be doped is preferably at least one of Li, Ni and Ti, more preferably Li.
When a silicon-based active material and graphite are combined, the mass ratio of the silicon-based active material to graphite (silicon-based active material/graphite) is preferably 2 or less, more preferably 1 or less, and even more preferably 0.5 or less. Although there is no particular lower limit for the mass ratio of the silicon-based active material to graphite, it is practically 0.05 or more.
When the negative electrode active material layer is formed, the mass (mg) (basis weight) of the negative electrode active material per unit area (cm 2 ) of the negative electrode active material layer is not particularly limited. It can be determined appropriately according to the designed battery capacity.
　負極活物質の、本発明の電極用組成物中における含有量は、特に限定されず、全固形分量に対して、１０～９９質量％であることが好ましく、３０～９８質量％がより好ましく、４５～９７質量％が更に好ましく、５５～９５質量％が特に好ましい。 The content of the negative electrode active material in the electrode composition of the present invention is not particularly limited, and is preferably 10 to 99% by mass, more preferably 30 to 98% by mass, based on the total solid content. 45 to 97 mass % is more preferred, and 55 to 95 mass % is particularly preferred.
　本発明において、負極活物質層を電池の充電により形成する場合、上記負極活物質に代えて、二次電池内に発生する周期律表第１族若しくは第２族に属する金属のイオンを用いることができる。このイオンを電子と結合させて金属として析出させることで、負極活物質層を形成できる。 In the present invention, when the negative electrode active material layer is formed by charging the battery, ions of a metal belonging to Group 1 or Group 2 of the periodic table generated in the secondary battery are used instead of the negative electrode active material. can be done. A negative electrode active material layer can be formed by combining this ion with an electron and depositing it as a metal.
（導電助剤）
　本発明の電極用組成物は、導電助剤を含有することもでき、特に負極活物質としてのケイ素系活物質は導電助剤と併用されることが好ましい。
　導電助剤としては、特に制限はなく、一般的な導電助剤として知られているものを用いることができる。例えば、電子伝導性材料である、アセチレンブラック、ケッチェンブラック、ファーネスブラック等のカーボンブラック類、ニードルコークス等の無定形炭素、気相成長炭素繊維若しくはカーボンナノチューブ等の炭素繊維類、グラフェン若しくはフラーレン等の炭素質材料であってもよいし、銅、ニッケル等の金属粉、金属繊維でもよく、ポリアニリン、ポリピロール、ポリチオフェン、ポリアセチレン、ポリフェニレン誘導体等の導電性高分子を用いてもよい。
　本発明において、活物質と導電助剤とを併用する場合、上記の導電助剤のうち、電池を充放電した際にＬｉの挿入と放出が起きず、活物質として機能しないものを導電助剤とする。したがって、導電助剤の中でも、電池を充放電した際に活物質層中において活物質として機能しうるものは、導電助剤ではなく活物質に分類する。電池を充放電した際に活物質として機能するか否かは、一義的ではなく、活物質との組み合わせにより決定される。 (Conductivity aid)
The electrode composition of the present invention can also contain a conductive aid, and it is particularly preferred that the silicon-based active material as the negative electrode active material is used in combination with the conductive aid.
There are no particular restrictions on the conductive aid, and any commonly known conductive aid can be used. For example, carbon blacks such as acetylene black, ketjen black, furnace black, etc., amorphous carbon such as needle coke, carbon fibers such as vapor-grown carbon fiber or carbon nanotube, graphene or fullerene, etc. , metal powders and fibers such as copper and nickel, and conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene and polyphenylene derivatives.
In the present invention, when an active material and a conductive aid are used in combination, among the above conductive aids, a conductive aid that does not cause insertion and release of Li during charging and discharging of the battery and does not function as an active material. and Therefore, among the conductive aids, those that can function as an active material in the active material layer during charging and discharging of the battery are classified as active materials rather than conductive aids. Whether or not it functions as an active material when the battery is charged/discharged is not univocally determined by the combination with the active material.
　導電助剤は、１種を単独で用いても、２種以上を組み合わせて用いてもよい。
　導電助剤の、本発明の電極用組成物中の含有量は、全固形分量に対して、０．５～６０質量％が好ましく、１．０～５０質量％がより好ましく、１．５～４０質量％が更に好ましく、２．５～３５質量％が特に好ましい。 A conductive support agent may be used individually by 1 type, or may be used in combination of 2 or more type.
The content of the conductive aid in the electrode composition of the present invention is preferably 0.5 to 60% by mass, more preferably 1.0 to 50% by mass, more preferably 1.5 to 1.5% by mass, based on the total solid content. 40% by mass is more preferred, and 2.5 to 35% by mass is particularly preferred.
　導電助剤の形状は、特に制限されず、粒子状が好ましい。導電助剤の平均粒径（体積基準のメジアン径Ｄ５０）は、特に限定されず、例えば、０．０１～５０μｍが好ましく、０．０２～１０．０μｍがより好ましい。
　市販品の導電助剤を用いる場合、導電助剤の平均粒径は製造元のカタログ記載の値を採用する。
　製造元の平均粒径の情報が入手できない場合又は合成した導電助剤を用いる場合は、導電助剤の平均粒径は、前述した負極活物質の平均粒径（水中での体積基準のメジアン径Ｄ５０）の測定方法を適用して得られた値を採用すればよい。 The shape of the conductive aid is not particularly limited, and is preferably particulate. The average particle diameter (volume-based median diameter D50) of the conductive aid is not particularly limited, and is preferably 0.01 to 50 μm, more preferably 0.02 to 10.0 μm.
When a commercially available conductive additive is used, the average particle diameter of the conductive additive adopts the value described in the manufacturer's catalog.
When information on the average particle size of the manufacturer is not available or when a synthetic conductive agent is used, the average particle size of the conductive agent is the average particle size of the negative electrode active material (volume-based median diameter in water D50 ) can be used.
（他の添加剤）
　本発明の電極用組成物は、上記各成分以外の他の成分として、所望により、リチウム塩、イオン液体、増粘剤、消泡剤、レベリング剤、脱水剤、酸化防止剤等を含有することができる。
　上記活物質、導電助剤、他の添加剤に関し、例えば、国際公開第２０１９／２０３３３４号、特開２０１５－４６３８９号公報等を参照することができる。 (other additives)
The electrode composition of the present invention may optionally contain lithium salts, ionic liquids, thickeners, antifoaming agents, leveling agents, dehydrating agents, antioxidants, etc. as other components in addition to the above components. can be done.
Regarding the active materials, conductive aids, and other additives, for example, International Publication No. 2019/203334, Japanese Patent Application Laid-Open No. 2015-46389, etc. can be referred to.
［二次電池用バインダー組成物の調製方法］
　本発明の二次電池用バインダー組成物は、水溶性高分子（Ｘ）、水溶性高分子（Ｙ）、重合体粒子、好ましくは、水、更には適宜に、任意の他の成分を、例えば通常用いる各種の混合機で混合することにより、混合物として、好ましくはスラリーとして、調製することができる。本発明の電極用組成物の場合は、上記に加えて活物質を、更には適宜に、導電助剤を、混合する。
　混合方法は特に制限されず、一括して混合してもよく、順次混合してもよい。また、複数の成分を混合して得られる混合物を他の成分と混合してもよく、例えば、水溶性高分子（Ｘ）、水溶性高分子（Ｙ）、活物質、導電助剤及び水を混合した後、水と重合体粒子を加えて更に混合して二次電池用バインダー組成物（電極用組成物）を得ることもできる。 [Method for preparing binder composition for secondary battery]
The binder composition for a secondary battery of the present invention contains a water-soluble polymer (X), a water-soluble polymer (Y), polymer particles, preferably water, and optionally any other component such as It can be prepared as a mixture, preferably as a slurry, by mixing with various commonly used mixers. In the case of the electrode composition of the present invention, in addition to the above, an active material and, optionally, a conductive aid are mixed.
The mixing method is not particularly limited, and may be mixed all at once or sequentially. Also, a mixture obtained by mixing a plurality of components may be mixed with other components, for example, water-soluble polymer (X), water-soluble polymer (Y), active material, conductive aid and water After mixing, water and polymer particles may be added and further mixed to obtain a secondary battery binder composition (electrode composition).
［電極シート］
　本発明の電極シートは、本発明の電極用組成物を用いて形成された層（電極活物質層、すなわち、負極活物質層又は正極活物質層）を有する。本発明の電極シートは、電極活物質層を有する電極シートであればよく、電極活物質層が、集電体等の基材上に形成されているシートでも、基材を有さず、電極活物質層（負極活物質層又は正極活物質層）だけで形成されているシートであってもよい。この電極シートは、通常、集電体上に電極活物質層を積層した構成のシートである。本発明の電極シートは、他の層として、例えば、剥離シート等の保護層、コート層を有してもよい。
　本発明の電極シートは、二次電池の負極活物質層又は正極活物質層を構成する材料、あるいは、負極集電体と負極活物質層の積層体（負極層）又は正極集電体と正極活物質層の積層体（正極層）として好適に用いることができる。 [Electrode sheet]
The electrode sheet of the present invention has a layer (electrode active material layer, ie, negative electrode active material layer or positive electrode active material layer) formed using the electrode composition of the present invention. The electrode sheet of the present invention may be any electrode sheet having an electrode active material layer. A sheet formed only of an active material layer (negative electrode active material layer or positive electrode active material layer) may be used. This electrode sheet is usually a sheet having a structure in which an electrode active material layer is laminated on a current collector. The electrode sheet of the present invention may have other layers such as a protective layer such as a release sheet and a coat layer.
The electrode sheet of the present invention is a material constituting a negative electrode active material layer or a positive electrode active material layer of a secondary battery, or a laminate (negative electrode layer) of a negative electrode current collector and a negative electrode active material layer, or a positive electrode current collector and a positive electrode. It can be suitably used as a laminate of active material layers (positive electrode layer).
　本発明の電極シートが集電体を有する場合、本発明の電極シートを構成する集電体は、電子伝達体であり、通常はフィルムシート状である。集電体は、活物質に応じて適宜選択することができる。
　正極集電体の構成材料としては、アルミニウム、アルミニウム合金、ステンレス鋼、ニッケル、及び、チタンが挙げられ、アルミニウム又はアルミニウム合金が好ましい。なお、正極集電体としては、アルミニウム又はステンレス鋼の表面にカーボン、ニッケル、チタン又は銀を処理させ、コート層（薄膜）を形成したものも挙げられる。
　負極集電体の構成材料としては、アルミニウム、銅、銅合金、ステンレス鋼、ニッケル、及び、チタンが挙げられ、アルミニウム、銅、銅合金、又は、ステンレス鋼が好ましい。なお、負極集電体としては、アルミニウム、銅、銅合金又はステンレス鋼の表面にカーボン、ニッケル、チタン又は銀を処理させ、コート層（薄膜）を形成したものも挙げられる。 When the electrode sheet of the present invention has a current collector, the current collector constituting the electrode sheet of the present invention is an electron mediator and is usually in the form of a film sheet. The current collector can be appropriately selected according to the active material.
Examples of the constituent material of the positive electrode current collector include aluminum, aluminum alloys, stainless steel, nickel, and titanium, with aluminum or aluminum alloys being preferred. Examples of the positive electrode current collector include those obtained by treating the surface of aluminum or stainless steel with carbon, nickel, titanium or silver to form a coat layer (thin film).
Materials constituting the negative electrode current collector include aluminum, copper, copper alloys, stainless steel, nickel, and titanium, with aluminum, copper, copper alloys, and stainless steel being preferred. Examples of the negative electrode current collector include those obtained by treating the surface of aluminum, copper, copper alloy or stainless steel with carbon, nickel, titanium or silver to form a coat layer (thin film).
　本発明の電極シートを構成する正極活物質層の厚さは特に制限されず、例えば、５～５００μｍとすることができ、２０～２００μｍが好ましい。
　また、本発明の電極シートを構成する正極集電体の厚さは特に制限されず、例えば、１０～１００μｍとすることができ、１０～５０μｍが好ましい。 The thickness of the positive electrode active material layer constituting the electrode sheet of the present invention is not particularly limited, and can be, for example, 5 to 500 μm, preferably 20 to 200 μm.
Moreover, the thickness of the positive electrode current collector constituting the electrode sheet of the present invention is not particularly limited, and can be, for example, 10 to 100 μm, preferably 10 to 50 μm.
　本発明の電極シートを構成する負極活物質層の厚さは特に制限されず、例えば、５～５００μｍとすることができ、２０～２００μｍが好ましい。
　また、本発明の電極シートを構成する負極集電体の厚さは特に制限されず、例えば、１０～１００μｍとすることができ、１０～５０μｍが好ましい。 The thickness of the negative electrode active material layer constituting the electrode sheet of the present invention is not particularly limited, and can be, for example, 5 to 500 μm, preferably 20 to 200 μm.
Moreover, the thickness of the negative electrode current collector constituting the electrode sheet of the present invention is not particularly limited, and can be, for example, 10 to 100 μm, preferably 10 to 50 μm.
［電極シートの製造方法］
　本発明の電極シートは、本発明の電極用組成物を用いて電極活物質層を形成することにより得ることができる。例えば、本発明の電極用組成物を用いて製膜することにより、本発明の電極シートを製造することができる。具体的には、集電体等を基材として、その上（他の層を介していてもよい）に本発明の電極用組成物を塗布して塗膜を形成し、これを乾燥して、基材上に活物質層（塗布乾燥層）を有する電極シートを得ることができる。
　また、本発明の二次電池は、上記電極シートの製造方法により得られた電極シートを二次電池の電極（正極及び負極）の少なくとも一方に組み込むことにより得ることができる。 [Manufacturing method of electrode sheet]
The electrode sheet of the present invention can be obtained by forming an electrode active material layer using the electrode composition of the present invention. For example, the electrode sheet of the present invention can be produced by forming a film using the electrode composition of the present invention. Specifically, a current collector or the like is used as a base material, and the electrode composition of the present invention is applied thereon (may be via another layer) to form a coating film, which is then dried. , an electrode sheet having an active material layer (coated and dried layer) on a substrate can be obtained.
Also, the secondary battery of the present invention can be obtained by incorporating the electrode sheet obtained by the electrode sheet manufacturing method into at least one of the electrodes (positive electrode and negative electrode) of the secondary battery.
［二次電池］
　本発明の二次電池は、正極活物質層及び負極活物質層の少なくとも１つの層が、本発明の電極用組成物を用いて形成された層である。好ましくは、本発明の二次電池は、正極活物質層とセパレータと負極活物質層とをこの順で有し、上記正極活物質層及び上記負極活物質層の少なくとも１つの層が、本発明の電極用組成物を用いて形成された層である。
　本発明の二次電池について、非水電解液二次電池の形態を例にして説明するが、本発明の二次電池は非水電解液二次電池に限定されるものではなく、二次電池全般を広く包含するものである。 [Secondary battery]
In the secondary battery of the present invention, at least one of the positive electrode active material layer and the negative electrode active material layer is a layer formed using the electrode composition of the present invention. Preferably, the secondary battery of the present invention has a positive electrode active material layer, a separator, and a negative electrode active material layer in this order, and at least one of the positive electrode active material layer and the negative electrode active material layer comprises the This is a layer formed using the electrode composition of
The secondary battery of the present invention will be described by taking the form of a non-aqueous electrolyte secondary battery as an example, but the secondary battery of the present invention is not limited to a non-aqueous electrolyte secondary battery. It encompasses all things broadly.
　本発明の好ましい一実施形態である非水電解液二次電池は、正極と、負極と、正極と負極との間に配されたセパレータとを含む構成を有する。正極は、正極集電体と、この正極集電体に接する正極活物質層とを有し、負極は、負極集電体と、この負極集電体に接する負極活物質層とを有する。本発明の非水電解液二次電池は、上記正極活物質層及び上記負極活物質層の少なくとも１つの層が、本発明の電極用組成物を用いて形成されている。なお、本発明の非水電解液二次電池には、正極活物質層及び負極活物質層のいずれか一方のみを有し、この有する電極活物質層が本発明の電極用組成物を用いて形成されている構成の非水電解液二次電池も含まれる。本発明の非水電解液二次電池は、正極と負極との間に非水電解液を満たすことにより、充放電により二次電池として機能する。 A non-aqueous electrolyte secondary battery, which is a preferred embodiment of the present invention, has a configuration including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. The positive electrode has a positive electrode current collector and a positive electrode active material layer in contact with the positive electrode current collector, and the negative electrode has a negative electrode current collector and a negative electrode active material layer in contact with the negative electrode current collector. In the non-aqueous electrolyte secondary battery of the present invention, at least one of the positive electrode active material layer and the negative electrode active material layer is formed using the electrode composition of the present invention. The non-aqueous electrolyte secondary battery of the present invention has only one of the positive electrode active material layer and the negative electrode active material layer, and the electrode active material layer having this electrode active material layer uses the electrode composition of the present invention. A non-aqueous electrolyte secondary battery having a formed structure is also included. The non-aqueous electrolyte secondary battery of the present invention functions as a secondary battery by charging and discharging by filling a non-aqueous electrolyte between the positive electrode and the negative electrode.
　図１は、一般的な非水電解液二次電池１０の積層構造を、電池として作動させる際の作動電極も含めて、模式化して示す断面図である。非水電解液二次電池１０は、負極側からみて、負極集電体１、負極活物質層２、セパレータ３、正極活物質層４、正極集電体５を、この順に有する積層構造を有している。負極活物質層２と正極活物質層４との間は非水電解液（図示せず）で満たされ、かつセパレータ３で分断されている。セパレータ３は空孔を有し、通常の電池の使用状態では電解液及びイオンをこの空孔により透過しながら正負極間を絶縁する正負極分離膜として機能する。このような構造により、例えばリチウムイオン二次電池であれば、充電時には外部回路を通って負極側に電子（ｅ－）が供給され、同時に電解液を介して正極からリチウムイオン（Ｌｉ＋）が移動してきて負極に蓄積される。一方、放電時には、負極に蓄積されたリチウムイオン（Ｌｉ＋）が電解液を介して正極側に戻され、作動部位６には電子が供給される。図示した例では、作動部位６に電球を採用しており、放電によりこれが点灯するようにされている。
　本発明において、負極集電体１と負極活物質層２とを合わせて負極と称し、正極活物質層４と正極集電体５とを合わせて正極と称している。 FIG. 1 is a schematic cross-sectional view showing a laminate structure of a general non-aqueous electrolyte secondary battery 10 including working electrodes when operated as a battery. The non-aqueous electrolyte secondary battery 10 has a laminated structure having, when viewed from the negative electrode side, a negative electrode current collector 1, a negative electrode active material layer 2, a separator 3, a positive electrode active material layer 4, and a positive electrode current collector 5 in this order. are doing. A space between the negative electrode active material layer 2 and the positive electrode active material layer 4 is filled with a non-aqueous electrolyte (not shown) and separated by the separator 3 . The separator 3 has pores, and functions as a positive/negative separator that insulates the positive/negative electrodes while permeating the electrolyte and ions through the pores under normal battery usage conditions. With such a structure, for example, in the case of a lithium ion secondary battery, during charging, electrons (e − ) are supplied to the negative electrode side through an external circuit, and at the same time lithium ions (Li + ) are released from the positive electrode through the electrolyte. It moves and accumulates at the negative electrode. On the other hand, during discharge, the lithium ions (Li + ) accumulated in the negative electrode are returned to the positive electrode side through the electrolyte, and electrons are supplied to the operating portion 6 . In the illustrated example, a light bulb is employed as the actuating portion 6, which is lit by discharge.
In the present invention, the negative electrode current collector 1 and the negative electrode active material layer 2 are collectively referred to as a negative electrode, and the positive electrode active material layer 4 and the positive electrode current collector 5 are collectively referred to as a positive electrode.
　本発明の二次電池は、本発明の二次電池用バインダー組成物ないし電極用組成物を用いて形成された正極活物質層及び負極活物質層の少なくともいずれか１つを具備してなること以外は、電解液（水系電解液、非水電解液）又は固体電解質材料等の電解質、セパレータ等のその他の各部材等は、特に制限されない。これらの材料及び部材等は、通常の二次電池に用いられるものを適宜に適用することができる。また、本発明の二次電池の作製方法についても、本発明の二次電池用バインダー組成物ないし電極用組成物を用いて正極活物質層及び負極活物質層の少なくともいずれか１つを形成すること以外は、通常の方法を適宜に採用することができる。これらの二次電池に通常使用される部材及び作製方法については、例えば、特開２０１６－２０１３０８号公報、特開２００５－１０８８３５号公報、特開２０１２－１８５９３８号公報及び国際公開第２０２０／０６７１０６号等を適宜に参照することができる。
　非水電解液の好ましい形態について、より詳しく説明する。 The secondary battery of the present invention comprises at least one of a positive electrode active material layer and a negative electrode active material layer formed using the secondary battery binder composition or electrode composition of the present invention. Other than that, the electrolytic solution (aqueous electrolytic solution, non-aqueous electrolytic solution) or electrolytes such as solid electrolyte materials, and other members such as separators are not particularly limited. As these materials, members, and the like, those used in ordinary secondary batteries can be appropriately applied. Further, in the method of manufacturing the secondary battery of the present invention, at least one of the positive electrode active material layer and the negative electrode active material layer is formed using the secondary battery binder composition or the electrode composition of the present invention. Other than that, conventional methods can be employed as appropriate. Regarding the members and manufacturing methods that are usually used in these secondary batteries, for example, JP 2016-201308, JP 2005-108835, JP 2012-185938 and WO 2020/067106 etc. can be referred to as appropriate.
A preferred form of the non-aqueous electrolyte will be described in more detail.
（電解質）
　非水電解液に用いる電解質は周期律表第１族又は第２族に属する金属イオンの塩が好ましい。使用する金属イオンの塩は非水電解液の使用目的により適宜選択される。例えば、リチウム塩、カリウム塩、ナトリウム塩、カルシウム塩、マグネシウム塩等が挙げられ、二次電池等に使用される場合には、出力の観点からリチウム塩が好ましい。非水電解液をリチウムイオン二次電池用電解液として用いる場合には、金属イオンの塩としてリチウム塩を選択すればよい。リチウム塩としては、リチウムイオン二次電池用電解液の電解質に通常用いられるリチウム塩が好ましく、例えば、以下のリチウム塩が挙げられる。 (Electrolytes)
The electrolyte used for the non-aqueous electrolyte is preferably a salt of a metal ion belonging to Group 1 or Group 2 of the periodic table. The metal ion salt to be used is appropriately selected depending on the intended use of the non-aqueous electrolyte. Examples include lithium salts, potassium salts, sodium salts, calcium salts, magnesium salts, etc. When used in secondary batteries and the like, lithium salts are preferred from the viewpoint of output. When a non-aqueous electrolyte is used as an electrolyte for a lithium ion secondary battery, a lithium salt may be selected as the metal ion salt. The lithium salt is preferably a lithium salt that is commonly used in electrolytes for lithium ion secondary batteries, and examples thereof include the following lithium salts.
（Ｌ－１）無機リチウム塩：ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＡｓＦ６、ＬｉＳｂＦ６等の無機フッ化物塩、ＬｉＣｌＯ４、ＬｉＢｒＯ４、ＬｉＩＯ４等の過ハロゲン酸塩、ＬｉＡｌＣｌ４等の無機塩化物塩等 (L-1) Inorganic lithium salts: inorganic fluoride salts such as LiPF 6 , LiBF 4 , LiAsF 6 and LiSbF 6 , perhalogenates such as LiClO 4 , LiBrO 4 and LiIO 4 , inorganic chloride salts such as LiAlCl 4 etc
（Ｌ－２）含フッ素有機リチウム塩：ＬｉＣＦ３ＳＯ３等のパーフルオロアルカンスルホン酸塩、ＬｉＮ（ＣＦ３ＳＯ２）２、ＬｉＮ（ＣＦ３ＣＦ２ＳＯ２）２、ＬｉＮ（ＦＳＯ２）２、ＬｉＮ（ＣＦ３ＳＯ２）（Ｃ４Ｆ９ＳＯ２）等のパーフルオロアルカンスルホニルイミド塩、ＬｉＣ（ＣＦ３ＳＯ２）３等のパーフルオロアルカンスルホニルメチド塩、Ｌｉ［ＰＦ５（ＣＦ２ＣＦ２ＣＦ３）］、Ｌｉ［ＰＦ４（ＣＦ２ＣＦ２ＣＦ３）２］、Ｌｉ［ＰＦ３（ＣＦ２ＣＦ２ＣＦ３）３］、Ｌｉ［ＰＦ５（ＣＦ２ＣＦ２ＣＦ２ＣＦ３）］、Ｌｉ［ＰＦ４（ＣＦ２ＣＦ２ＣＦ２ＣＦ３）２］、Ｌｉ［ＰＦ３（ＣＦ２ＣＦ２ＣＦ２ＣＦ３）３］等のパーフルオロアルキルフッ化リン酸塩等 (L-2) Fluorine-containing organic lithium salts: Perfluoroalkanesulfonates such as LiCF 3 SO 3 , LiN(CF 3 SO 2 ) 2 , LiN(CF 3 CF 2 SO 2 ) 2 , LiN(FSO 2 ) 2 , perfluoroalkanesulfonylimide salts such as LiN( CF3SO2 ) ( C4F9SO2 ) , perfluoroalkanesulfonylmethide salts such as LiC( CF3SO2 ) 3 , Li [ PF5 ( CF2 CF2CF3 ) ], Li[ PF4 ( CF2CF2CF3 ) 2 ] , Li [ PF3 (CF2CF2CF3 ) 3 ] , Li [ PF5 ( CF2CF2CF2CF3 )], Li[PF 4 (CF 2 CF 2 CF 2 CF 3 ) 2 ], Li[PF 3 (CF 2 CF 2 CF 2 CF 3 ) 3 ], perfluoroalkyl fluoride phosphates, etc.
（Ｌ－３）オキサラトボレート塩：リチウムビス（オキサラト）ボレート、リチウムジフルオロオキサラトボレート等 (L-3) Oxalatoborate salts: lithium bis(oxalato)borate, lithium difluorooxalatoborate, etc.
　これらのなかでも、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＡｓＦ６、ＬｉＳｂＦ６、ＬｉＣｌＯ４、Ｌｉ（Ｒｆ１ＳＯ３）、ＬｉＮ（Ｒｆ１ＳＯ２）２、ＬｉＮ（ＦＳＯ２）２、又は、ＬｉＮ（Ｒｆ１ＳＯ２）（Ｒｆ２ＳＯ２）等のリチウムイミド塩が好ましく、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＮ（Ｒｆ１ＳＯ２）２、ＬｉＮ（ＦＳＯ２）２、又は、ＬｉＮ（Ｒｆ１ＳＯ２）（Ｒｆ２ＳＯ２）等のリチウムイミド塩がより好ましい。ここで、Ｒｆ１及びＲｆ２はそれぞれパーフルオロアルキル基を示し、炭素数は１～６であることが好ましい。
　なお、非水電解液に用いる電解質は、１種を単独で使用しても、２種以上を任意に組み合わせてもよい。 Among these, LiPF6 , LiBF4 , LiAsF6, LiSbF6 , LiClO4 , Li( Rf1SO3 ) , LiN( Rf1SO2 ) 2 , LiN( FSO2 ) 2 , or LiN( Rf1 SO 2 )(R f2 SO 2 ) are preferred, LiPF 6 , LiBF 4 , LiN(R f1 SO 2 ) 2 , LiN(FSO 2 ) 2 or LiN(R f1 SO 2 )(R Lithium imide salts such as f2SO2 ) are more preferred. Here, each of R f1 and R f2 represents a perfluoroalkyl group, preferably having 1 to 6 carbon atoms.
In addition, the electrolyte used for a nonaqueous electrolyte may be used individually by 1 type, or may combine 2 or more types arbitrarily.
　非水電解液における電解質（好ましくは周期律表第１族又は第２族に属する金属のイオン若しくはその金属塩）の塩濃度は非水電解液の使用目的により適宜選択されるが、一般的には非水電解液の全質量中１０～５０質量％であり、好ましくは１５～３０質量％である。モル濃度としては０．５～１．５Ｍが好ましい。なお、イオンの濃度として評価するときには、その好適に適用される金属との塩換算で算出すればよい。 The salt concentration of the electrolyte in the non-aqueous electrolyte (preferably the ion of a metal belonging to Group 1 or Group 2 of the periodic table or a metal salt thereof) is appropriately selected depending on the purpose of use of the non-aqueous electrolyte, but generally is 10 to 50% by mass, preferably 15 to 30% by mass, of the total mass of the non-aqueous electrolyte. The molar concentration is preferably 0.5-1.5M. When the concentration of ions is evaluated, it may be calculated by salt conversion with the suitably applied metal.
（非水溶媒）
　非水電解液は、非水溶媒を含有する。
　非水溶媒としては、非プロトン性有機溶媒が好ましく、中でも炭素数が２～１０の非プロトン性有機溶媒がより好ましい。
　このような非水溶媒としては、鎖状若しくは環状のカーボネート化合物、ラクトン化合物、鎖状若しくは環状のエーテル化合物、エステル化合物、ニトリル化合物、アミド化合物、オキサゾリジノン化合物、ニトロ化合物、鎖状又は環状のスルホン若しくはスルホキシド化合物、リン酸エステル化合物が挙げられる。
　なお、エーテル結合、カルボニル結合、エステル結合又はカーボネート結合を有する化合物が好ましい。これらの化合物は置換基を有していてもよく、有していてもよい置換基としては、例えば上述の置換基群Ｔから選ばれる置換基が挙げられる。 (Non-aqueous solvent)
The non-aqueous electrolyte contains a non-aqueous solvent.
As the non-aqueous solvent, an aprotic organic solvent is preferable, and an aprotic organic solvent having 2 to 10 carbon atoms is more preferable.
Examples of such non-aqueous solvents include chain or cyclic carbonate compounds, lactone compounds, chain or cyclic ether compounds, ester compounds, nitrile compounds, amide compounds, oxazolidinone compounds, nitro compounds, chain or cyclic sulfones or Examples include sulfoxide compounds and phosphate ester compounds.
A compound having an ether bond, a carbonyl bond, an ester bond or a carbonate bond is preferred. These compounds may have a substituent, and examples of the substituent which may have include a substituent selected from the above-described substituent group T.
　非水溶媒としては、例えば、エチレンカーボネート、フッ化エチレンカーボネート、ビニレンカーボネート、プロピレンカーボネート、ブチレンカーボネート、ジメチルカーボネート、ジエチルカーボネート、エチルメチルカーボネート、メチルプロピルカーボネート、γ－ブチロラクトン、γ－バレロラクトン、１，２－ジメトキシエタン、テトラヒドロフラン、２－メチルテトラヒドロフラン、テトラヒドロピラン、１，３－ジオキソラン、４－メチル－１，３－ジオキソラン、１，３－ジオキサン、１，４－ジオキサン、酢酸メチル、酢酸エチル、プロピオン酸メチル、プロピオン酸エチル、酪酸メチル、イソ酪酸メチル、トリメチル酢酸メチル、トリメチル酢酸エチル、アセトニトリル、グルタロニトリル、アジポニトリル、メトキシアセトニトリル、３－メトキシプロピオニトリル、Ｎ，Ｎ－ジメチルホルムアミド、Ｎ－メチルピロリジノン、Ｎ－メチルオキサゾリジノン、Ｎ，Ｎ’－ジメチルイミダゾリジノン、ニトロメタン、ニトロエタン、スルホラン、リン酸トリメチル、ジメチルスルホキシドあるいはジメチルスルホキシドリン酸等が挙げられる。これらは、１種単独で用いても２種以上を併用してもよい。中でも、エチレンカーボネート、プロピレンカーボネート、ジメチルカーボネート、ジエチルカーボネート及びエチルメチルカーボネート、γ－ブチロラクトンからなる群のうちの少なくとも１種が好ましく、エチレンカーボネート又はプロピレンカーボネート等の高粘度（高誘電率）溶媒（例えば、比誘電率ε≧３０）とジメチルカーボネート、エチルメチルカーボネート又はジエチルカーボネート等の低粘度溶媒（例えば、粘度≦１ｍＰａ・ｓ）との組み合わせがより好ましい。このような組み合わせの混合溶媒とすることで、電解質塩の解離性及びイオンの移動度が向上する。
　なお、本発明に用いられる非水溶媒は、これらに限定されるものではない。 Non-aqueous solvents include, for example, ethylene carbonate, fluoroethylene carbonate, vinylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, methylpropyl carbonate, γ-butyrolactone, γ-valerolactone, 1, 2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,3-dioxane, 1,4-dioxane, methyl acetate, ethyl acetate, propion Methyl acid, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethylacetate, ethyl trimethylacetate, acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, N,N-dimethylformamide, N-methyl pyrrolidinone, N-methyloxazolidinone, N,N'-dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, trimethyl phosphate, dimethylsulfoxide or dimethylsulfoxyphosphoric acid; These may be used individually by 1 type, or may use 2 or more types together. Among them, at least one selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and γ-butyrolactone is preferable, and a high viscosity (high dielectric constant) solvent such as ethylene carbonate or propylene carbonate (for example, , dielectric constant ε≧30) and a low-viscosity solvent such as dimethyl carbonate, ethylmethyl carbonate or diethyl carbonate (for example, viscosity ≦1 mPa·s) is more preferable. By using such a combination of mixed solvents, the dissociation property of the electrolyte salt and the mobility of ions are improved.
In addition, the non-aqueous solvent used in the present invention is not limited to these.
　本発明の二次電池は、例えば、ノートパソコン、ペン入力パソコン、モバイルパソコン、電子ブックプレーヤー、携帯電話、コードレスフォン子機、ページャー、ハンディーターミナル、携帯ファックス、携帯コピー、携帯プリンター、ヘッドフォンステレオ、ビデオムービー、液晶テレビ、ハンディークリーナー、ポータブルＣＤ、ミニディスク、電気シェーバー、トランシーバー、電子手帳、電卓、携帯テープレコーダー、ラジオ、バックアップ電源、メモリーカード等の電子機器に搭載することができる。また、民生用として、自動車、電動車両、モーター、照明器具、玩具、ゲーム機器、ロードコンディショナー、時計、ストロボ、カメラ、医療機器（ペースメーカー、補聴器、肩もみ機等）等に搭載することができる。更に、各種軍需用、及び、宇宙用として用いることができる。また、太陽電池と組み合わせることもできる。 The secondary battery of the present invention can be used, for example, in notebook computers, pen-input computers, mobile computers, e-book players, mobile phones, cordless phone slaves, pagers, handy terminals, mobile faxes, mobile copiers, mobile printers, headphone stereos, and videos. It can be installed in electronic equipment such as movies, liquid crystal televisions, handy cleaners, portable CDs, minidiscs, electric shavers, transceivers, electronic notebooks, calculators, portable tape recorders, radios, backup power supplies, memory cards, and the like. In addition, for consumer use, it can be installed in automobiles, electric vehicles, motors, lighting equipment, toys, game devices, road conditioners, watches, strobes, cameras, medical devices (pacemakers, hearing aids, shoulder massagers, etc.). Furthermore, it can be used for various military uses and for space use. It can also be combined with a solar cell.
　実施例に基づき本発明について更に詳細に説明する。なお、本発明は本発明で規定すること以外は、これらの実施例により限定して解釈されるものではない。また、室温とは、特段の断りのない限り、２７℃を意味する。組成比、配合量比、含有量については、特段の断りのない限り、質量基準を意味する。 The present invention will be described in more detail based on examples. It should be noted that the present invention is not to be construed as being limited by these examples, except as defined by the present invention. Further, room temperature means 27° C. unless otherwise specified. Unless otherwise specified, the composition ratio, compounding ratio, and content are based on mass.
［水溶性高分子（Ｘ）の合成］
　後記表１に記載するバインダー組成物１及びｃ１～ｃ３の調製に用いる水溶性高分子（Ｘ）を合成した。
　具体的には、還流冷却管、ガス導入コックを付した１Ｌ三口フラスコに、蒸留水　３３７．５ｇを加えた。流速２００ｍＬ／ｍｉｎにて窒素ガスを６０分間導入した後に、７５℃に昇温した。別容器にて調製した液（アクリルアミド（富士フイルム和光純薬社製）　７５．０ｇ、蒸留水　７５．０ｇ、ＶＡ－０５７（商品名、富士フイルム和光純薬社製の水溶性アゾ重合開始剤）　０．５３ｇを室温で撹拌して混合した液）を、１Ｌ三口フラスコ中の蒸留水に１時間かけて滴下した。滴下完了後、７５℃で３時間撹拌を続けた。室温まで冷却し、バインダー組成物１及びｃ１～ｃ３の調製に用いる水溶性高分子（Ｘ）（ポリアクリルアミド（ＰＡＡｍ））の水溶液を得た。固形分濃度は１４．０質量％、Ｍｗは３４７０００、Ｍｗ／Ｍｎは２．４０であった。 [Synthesis of water-soluble polymer (X)]
A water-soluble polymer (X) used for preparing binder compositions 1 and c1 to c3 shown in Table 1 below was synthesized.
Specifically, 337.5 g of distilled water was added to a 1 L three-necked flask equipped with a reflux condenser and a gas inlet cock. After introducing nitrogen gas at a flow rate of 200 mL/min for 60 minutes, the temperature was raised to 75°C. Liquid prepared in a separate container (acrylamide (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) 75.0 g, distilled water 75.0 g, VA-057 (trade name, water-soluble azo polymerization initiator manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) 0.53 g was stirred at room temperature and mixed) was added dropwise to distilled water in a 1 L three-necked flask over 1 hour. After completion of dropping, stirring was continued at 75° C. for 3 hours. After cooling to room temperature, an aqueous solution of water-soluble polymer (X) (polyacrylamide (PAAm)) used for preparing binder compositions 1 and c1 to c3 was obtained. Solid concentration was 14.0% by mass, Mw was 347000, and Mw/Mn was 2.40.
　上記水溶性高分子（Ｘ）の合成例において、アクリルアミドに代えてアクリルアミド及びアクリル酸を、アクリルアミド／アクリル酸＝９７／３（質量比）で用いたこと以外は、バインダー組成物１及びｃ１～ｃ３の調製に用いる水溶性高分子（Ｘ）の水溶液の調製と同様にして、後記表１に記載するバインダー組成物２の調製に用いる水溶性高分子（Ｘ）の水溶液を得た。 Binder compositions 1 and c1 to c3 except that acrylamide and acrylic acid were used in place of acrylamide in the synthesis example of the water-soluble polymer (X) at an acrylamide/acrylic acid ratio of 97/3 (mass ratio). An aqueous solution of the water-soluble polymer (X) used in the preparation of the binder composition 2 shown in Table 1 below was obtained in the same manner as in the preparation of the aqueous solution of the water-soluble polymer (X) used in the preparation of .
　上記のバインダー組成物２の調製に用いる水溶性高分子（Ｘ）の水溶液の調製において、後記表１に記載する原料化合物（モノマー）を後記表１に記載の質量比で用いたこと以外は、バインダー組成物２の調製に用いる水溶性高分子（Ｘ）の水溶液の調製と同様にして、バインダー組成物３～１１、ｃ４及びｃ５の調製に用いる水溶性高分子（Ｘ）の水溶液を調製した。
　なお、バインダー組成物ｃ５に用いる水溶性高分子（Ｘ）の水溶液の調製では、アクリルアミド／アクリル酸＝７５／２５（質量比）で重合したコポリマーの水溶液に１０％水酸化リチウム水溶液を添加して、ｐＨ８となるよう調整（中和）することで、アクリルアミド／アクリル酸リチウム＝７５／２５（質量比）の水溶液を得た。 In the preparation of the aqueous solution of the water-soluble polymer (X) used for the preparation of the binder composition 2, except that the raw material compounds (monomers) described in Table 1 below were used at the mass ratios described in Table 1 below, Aqueous solutions of the water-soluble polymer (X) used for the preparation of the binder compositions 3 to 11, c4 and c5 were prepared in the same manner as the aqueous solution of the water-soluble polymer (X) used for the preparation of the binder composition 2. .
In the preparation of the aqueous solution of the water-soluble polymer (X) used for the binder composition c5, a 10% lithium hydroxide aqueous solution was added to the aqueous solution of the copolymer polymerized with acrylamide/acrylic acid = 75/25 (mass ratio). , and adjusted (neutralized) to pH 8 to obtain an aqueous solution of acrylamide/lithium acrylate=75/25 (mass ratio).
　上記で合成した水溶性高分子について、上述のようにして重量平均分子量（Ｍｗ）及び数平均分子量（Ｍｎ）を測定し、分子量分布（Ｍｗ／Ｍｎ）を算出した。得られた結果を、表１にまとめて示す。 For the water-soluble polymer synthesized above, the weight average molecular weight (Mw) and number average molecular weight (Mn) were measured as described above, and the molecular weight distribution (Mw/Mn) was calculated. The obtained results are summarized in Table 1.
［重合体粒子の合成］
　国際公開第２０１５／１８６３６３の段落［０１４１］に記載の「粒子状重合体Ｚ１」を、同段落の記載を参照して合成した。 [Synthesis of polymer particles]
"Particulate polymer Z1" described in paragraph [0141] of International Publication No. 2015/186363 was synthesized with reference to the description in the same paragraph.
（引張弾性率の算出）
　剥離性のポリエチレンテレフタレート（ＰＥＴ）フィルム（縦５ｃｍ、横０．５ｃｍ、膜厚０．１ｍｍ）に、後記表１に記載する各水溶性高分子（Ｘ）の水溶液又は重合体粒子（ラテックスポリマー）を塗布して乾燥させた。ＰＥＴフィルムから、水溶性高分子（Ｘ）又は重合体粒子のシート（縦５ｃｍ、横０．５ｃｍ、膜厚０．０３０～０．１５０ｍｍ）を剥離して試験片を得た。試験片の縦（長さ）方向において、端から１ｃｍの位置及び他方の端から１ｃｍの位置をそれぞれ治具に固定し、引張試験機（商品名：ＦＧＳ－ＴＶ、日本電産シンポ社製）を用いて引張試験を行った。なお、この試験は２３℃、引張速度５ｍｍ／分で行った。変位に対する荷重を測定した結果から得られる応力－ひずみ曲線の弾性領域の平均値から引張弾性率を算出した。得られた引張弾性率を後記表１に示す。 (Calculation of tensile modulus)
An aqueous solution or polymer particles (latex polymer) of each water-soluble polymer (X) described in Table 1 below was applied to a peelable polyethylene terephthalate (PET) film (length 5 cm, width 0.5 cm, film thickness 0.1 mm). was applied and dried. A sheet of water-soluble polymer (X) or polymer particles (length 5 cm, width 0.5 cm, film thickness 0.030 to 0.150 mm) was peeled off from the PET film to obtain a test piece. In the vertical (length) direction of the test piece, 1 cm from one end and 1 cm from the other end are fixed to jigs, respectively, and a tensile tester (trade name: FGS-TV, manufactured by Nidec-Shimpo) A tensile test was performed using In addition, this test was performed at 23° C. and a tensile speed of 5 mm/min. The tensile modulus was calculated from the average value of the elastic region of the stress-strain curve obtained from the results of measuring the load against displacement. The obtained tensile modulus is shown in Table 1 below.
［バインダー組成物の調製］
　後記表１に記載するバインダー組成物１を調製した。
　具体的には、６０ｍＬの軟膏容器（馬野化学社製）に、水溶性高分子（Ｘ）（ＰＡＡｍ）の水溶液　７．５０ｇ（固形分量１．０５ｇ）、水溶性高分子（Ｙ）（カルボキシメチルセルロース（ＣＭＣ））の水溶液　８．００ｇ（固形分量０．４０ｇ）を加え、あわとり練太郎（商品名、ＴＨＩＮＫＹ社製）を用いて２０００ｒｐｍで４分間分散した。更に、分散した液に重合体粒子（ナルスターＳＲ－１５１（商品名、日本エイアンドエル社製のスチレンブタジエンゴムラテックス））　２．０９ｇ（液媒体として水を含む、固形分量１．０５ｇ）を加え、あわとり練太郎を用いて２０００ｒｐｍで２分間分散することにより、バインダー組成物１を得た。 [Preparation of binder composition]
A binder composition 1 described in Table 1 below was prepared.
Specifically, in a 60 mL ointment container (manufactured by Umano Kagaku), 7.50 g of an aqueous solution of water-soluble polymer (X) (PAAm) (solid content: 1.05 g), water-soluble polymer (Y) (carboxymethyl cellulose (CMC)) was added, and dispersed for 4 minutes at 2000 rpm using an Awatori Mixer (trade name, manufactured by THINKY). Furthermore, 2.09 g of polymer particles (Nalstar SR-151 (trade name, styrene-butadiene rubber latex manufactured by Nippon A&L Co., Ltd.)) (containing water as a liquid medium, solid content of 1.05 g) was added to the dispersed liquid, and foam was added. Binder composition 1 was obtained by dispersing at 2000 rpm for 2 minutes using a Tori Mixer.
　バインダー組成物１の調製において、後記表１に記載する組成を採用したこと以外は、バインダー組成物１の調製と同様にして、バインダー組成物２～１１及びｃ１～ｃ５を調製した。 Binder compositions 2 to 11 and c1 to c5 were prepared in the same manner as the binder composition 1, except that the composition shown in Table 1 below was used in the preparation of the binder composition 1.
（破断エネルギーの算出）
　剥離性ＰＥＴフィルム（縦５ｃｍ、横０．５ｃｍ、膜厚０．１ｍｍ）に、後記表１に記載する各バインダー組成物を塗布して乾燥させることにより、ＰＥＴフィルム上にポリマーシートを形成した。ＰＥＴフィルムから、ポリマーシート（縦５ｃｍ、横０．５ｃｍ、膜厚０．０３０～０．１５０ｍｍ）を剥離して試験片を得た。試験片の縦（長さ）方向において、端から１ｃｍの位置及び他方の端から１ｃｍの位置をそれぞれ治具に固定し、引張試験機（商品名：ＦＧＳ－ＴＶ、日本電産シンポ社製）を用いて引張試験を行った。なお、この試験は２３℃、引張速度５ｍｍ／分で行った。変位に対する荷重を測定した結果から得られる応力－ひずみ曲線から破断エネルギーを算出した。得られた破断エネルギーを下記評価ランクに当てはめて評価した。結果を後記表１に示す。
 
－評価ランク－
　４：　１．５ＭＰａ以上
　３：　１．０ＭＰａ以上、１．５ＭＰａ未満
　２：　０．５ＭＰａ以上、１．０ＭＰａ未満
　１：　０．５ＭＰａ未満 (Calculation of breaking energy)
A polymer sheet was formed on a peelable PET film (5 cm long, 0.5 cm wide, 0.1 mm film thickness) by applying each binder composition described in Table 1 below and drying the coating. A test piece was obtained by peeling a polymer sheet (5 cm long, 0.5 cm wide, 0.030 to 0.150 mm film thickness) from the PET film. In the vertical (length) direction of the test piece, 1 cm from one end and 1 cm from the other end are fixed to jigs, respectively, and a tensile tester (trade name: FGS-TV, manufactured by Nidec-Shimpo) A tensile test was performed using This test was conducted at 23° C. and a tensile speed of 5 mm/min. The breaking energy was calculated from the stress-strain curve obtained from the results of measuring the load against displacement. The obtained breaking energy was applied to the following evaluation ranks and evaluated. The results are shown in Table 1 below.

-Evaluation Rank-
4: 1.5 MPa or more 3: 1.0 MPa or more and less than 1.5 MPa 2: 0.5 MPa or more and less than 1.0 MPa 1: less than 0.5 MPa
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
＜表１の注＞
「－」：該当する成分を含有しないこと、該当する特性を評価していないことを示す。
ＰＡＡｍ：上記のようにして重合したポリアクリルアミド
ＡＡｍ／ＡＡ（９７／３）：アクリルアミド／アクリル酸＝９７／３（質量比）で上記のようにして重合したコポリマー
ＡＡｍ／ＡＡ（８５／１５）：アクリルアミド／アクリル酸＝８５／１５（質量比）で上記のようにして重合したコポリマー
ＡＡｍ／ＨＥＡ（８５／１５）：アクリルアミド／２－ヒドロキシエチルアクリレート＝８５／１５（質量比）で上記のようにして重合したコポリマー
ＡＡｍ／ＡＮ（８０／２０）：アクリルアミド／アクリロニトリル＝８０／２０（質量比）で上記のようにして重合したコポリマー
ＡＡｍ／ＨＥＡＡ（８０／２０）：アクリルアミド／Ｎ－（２－ヒドロキシエチル）アクリルアミド＝８０／２０（質量比）で上記のようにして重合したコポリマー
ＡＡｍ／ＨＥＡ（６０／４０）：アクリルアミド／２－ヒドロキシエチルアクリレート＝６０／４０（質量比）で上記のようにして重合したコポリマー
ＡＡｍ／ＡＡ（８０／２０）：アクリルアミド／アクリル酸＝８０／２０（質量比）で上記のようにして重合したコポリマー
ＡＡｍ／ＨＥＡ（８０／２０）：アクリルアミド／２－ヒドロキシエチルアクリレート＝８０／２０（質量比）で上記のようにして重合したコポリマー
ＡＡｍ／４ＨＢＡ（８０／２０）：アクリルアミド／４－ヒドロキシブチルアクリレート＝８０／２０（質量比）で上記のようにして重合したコポリマー
ＡＡｍ／ＡＮ（７０／３０）：アクリルアミド／アクリロニトリル＝７０／３０（質量比）で上記のようにして重合したコポリマー
ＡＡｍ／ＨＥＡ（１０／９０）：アクリルアミド／２－ヒドロキシエチルアクリレート＝１０／９０（質量比）で上記のようにして重合したコポリマー
ＡＡｍ／ＡＡＬｉ（７５／２５）：アクリルアミド／アクリル酸リチウム＝７５／２５（質量比）で上記のようにして重合したコポリマー。Ｍｗ、Ｍｎ及びＭｗ／Ｍｎは、中和前のコポリマーを測定して得た値である。
ＣＭＣ：セロゲンＷＳ－Ｃ（商品名）、第一工業製薬社製、カルボキシメチルセルロース（エーテル化度０．６６）
（ＰＡＡｍ、ＡＡｍ／ＡＡ等の表１中の水溶性高分子（Ｘ）の欄に記載する高分子、及びＣＭＣは、２０℃において水に対する溶解度が、いずれも１０ｇ／Ｌ－Ｈ２Ｏ以上であった。）
ＳＲ－１５１：ナルスターＳＲ－１５１（商品名）、日本エイアンドエル社製のスチレンブタジエンゴム
ＳＲ－１５３：ナルスターＳＲ－１５３（商品名）、日本エイアンドエル社製のスチレンブタジエンゴム
粒子状重合体Ｚ１：国際公開第２０１５／１８６３６３号の段落［０１４１］の記載に従って重合したスチレン－ブタジエン共重合体よりなる粒子状重合体Ｚ１
（上記ＳＲ－１５１、ＳＲ－１５３及び粒子状重合体Ｚ１は、２０℃において水に対する溶解度が、いずれも１０ｇ／Ｌ－Ｈ２Ｏ未満であった。）
含有量（％）：バインダー組成物に含まれる各ポリマー（固形分）の合計に占める各ポリマー（固形分）の割合を質量基準で示したものである（表１中の「％」は「質量％」を意味する。）。
Ｍｗ：水溶性高分子（Ｘ）の重量平均分子量
Ｍｎ：水溶性高分子（Ｘ）の数量平均分子量
Ｍｗ／Ｍｎ：水溶性高分子（Ｘ）の分子量分布
　ＳＲ－１５１のＴｇは２点（－２７℃と１５℃）観測される（日本エイアンドエル社のカタログ値）。 <Note to Table 1>
"-": Indicates that the corresponding component is not contained and the corresponding property has not been evaluated.
PAAm: Polyacrylamide polymerized as above AAm/AA (97/3): Copolymer AAm/AA (85/15) polymerized as above with acrylamide/acrylic acid = 97/3 (weight ratio): Copolymer AAm/HEA (85/15) polymerized as described above with acrylamide/acrylic acid = 85/15 (weight ratio): AAm/AN (80/20) polymerized as described above with acrylamide/acrylonitrile = 80/20 (weight ratio): acrylamide/N-(2-hydroxy Copolymer AAm/HEA (60/40) polymerized as above with ethyl) acrylamide = 80/20 (by weight): Acrylamide/2-hydroxyethyl acrylate = 60/40 (by weight) as above Polymerized copolymer AAm/AA (80/20): copolymer AAm/HEA (80/20) polymerized as above with acrylamide/acrylic acid = 80/20 (weight ratio): acrylamide/2-hydroxyethyl acrylate = Copolymer AAm/4HBA (80/20) polymerized as above with 80/20 (ratio by weight): Copolymer AAm polymerized as above with acrylamide/4-hydroxybutyl acrylate=80/20 (ratio by weight) /AN (70/30): copolymer polymerized as above with acrylamide/acrylonitrile = 70/30 (weight ratio) AAm/HEA (10/90): acrylamide/2-hydroxyethyl acrylate = 10/90 (weight ratio) AAm/AALi (75/25) copolymer polymerized as described above with acrylamide/lithium acrylate=75/25 (weight ratio). Mw, Mn and Mw/Mn are values obtained by measuring the copolymer before neutralization.
CMC: Celogen WS-C (trade name), manufactured by Daiichi Kogyo Seiyaku Co., Ltd., carboxymethyl cellulose (degree of etherification 0.66)
(The polymers listed in the column of water-soluble polymer (X) in Table 1, such as PAAm and AAm/AA, and CMC all have a solubility in water of 10 g/L-H 2 O or more at 20°C. there were.)
SR-151: Nalstar SR-151 (trade name), styrene-butadiene rubber manufactured by Nippon A&L Co., Ltd. SR-153: Nalstar SR-153 (trade name), styrene-butadiene rubber manufactured by Japan A&L Co., Ltd. Particulate polymer Z1: International publication Particulate polymer Z1 consisting of a styrene-butadiene copolymer polymerized according to paragraph [0141] of 2015/186363
(All of the above SR-151, SR-153 and particulate polymer Z1 had a solubility in water of less than 10 g/L-H 2 O at 20°C.)
Content (%): The ratio of each polymer (solid content) to the total of each polymer (solid content) contained in the binder composition is shown on a mass basis (“%” in Table 1 means “mass %”.).
Mw: Weight average molecular weight of water-soluble polymer (X) Mn: Number average molecular weight of water-soluble polymer (X) Mw/Mn: Molecular weight distribution of water-soluble polymer (X) Tg of SR-151 is 2 points (- 27° C. and 15° C.) are observed (catalog values of Japan A&L Co., Ltd.).
［負極用組成物の調製１］
　以下、後記表２－Ａ及び表２－Ｂをまとめて表２と称する。
　後記表２に記載する負極用組成物１を調製した。この負極用組成物は、本発明のバインダー組成物の一実施形態である。
　６０ｍＬの軟膏容器（馬野化学社製）にカーボンコートされた酸化ケイ素（炭素元素の含有量の割合１．３質量％、平均粒径：５μｍ、大阪チタニウムテクノロジーズ社製）　１．７８ｇ、黒鉛（商品名：ＭＡＧ－Ｄ、昭和電工マテリアルズ社製）　７．１２ｇ、アセチレンブラック（商品名：デンカブラック、デンカ社製）　０．６０ｇ、上記ＰＡＡｍ　１．４９ｇ（固形分量０．２０８ｇ）、上記ＣＭＣ　１．６８ｇ（固形分量０．０８４ｇ）、蒸留水　３．８ｇを加え、あわとり練太郎を用いて２０００ｒｐｍで６分間分散した。分散した液に蒸留水を１．８ｇ加え、あわとり練太郎を用いて２０００ｒｐｍで１２分間分散した。更に、分散した液に上記ナルスターＳＲ－１５１　０．４１ｇ（固形分量０．２０８ｇ）を加え、あわとり練太郎を用いて２０００ｒｐｍで３分間分散することにより、負極用組成物１を得た。 [Preparation of negative electrode composition 1]
Hereinafter, Tables 2-A and 2-B are collectively referred to as Table 2.
A negative electrode composition 1 shown in Table 2 below was prepared. This negative electrode composition is one embodiment of the binder composition of the present invention.
1.78 g of carbon-coated silicon oxide (content ratio of carbon element: 1.3% by mass, average particle size: 5 μm, manufactured by Osaka Titanium Technologies Co., Ltd.) in a 60 mL ointment container (manufactured by Umano Kagaku Co., Ltd.), graphite (product Name: MAG-D, manufactured by Showa Denko Materials Co., Ltd.) 7.12 g, acetylene black (trade name: Denka Black, manufactured by Denka) 0.60 g, PAAm 1.49 g (solid content 0.208 g), CMC 1 .68 g (0.084 g of solid content) and 3.8 g of distilled water were added, and dispersed at 2000 rpm for 6 minutes using a mixer. 1.8 g of distilled water was added to the dispersed liquid, and dispersed at 2000 rpm for 12 minutes using a mixer. Further, 0.41 g of Nalstar SR-151 (solid content: 0.208 g) was added to the dispersed liquid, and the mixture was dispersed at 2000 rpm for 3 minutes using a stirrer to obtain a negative electrode composition 1.
　負極用組成物１の調製において、負極用組成物１の組成に代えて後記表２に記載する組成を採用したこと以外は、負極用組成物１の調製と同様にして、負極用組成物２～１１及びｃ１～ｃ５を調製した。 In the preparation of negative electrode composition 1, negative electrode composition 2 was prepared in the same manner as negative electrode composition 1, except that the composition shown in Table 2 below was used instead of the composition of negative electrode composition 1. ~11 and c1-c5 were prepared.
（負極用組成物の分散性の評価）
　グラインドゲージ（ＥＲＩＣＨＳＥＮ社製、モデル２３２）を用いて、調製した負極用組成物に含まれる固体粒子（後記表２に記載の高容量活物質、活物質、導電助剤及び重合体粒子の全体）の平均粒径（体積基準のメジアン径Ｄ５０）を測定した。得られた平均粒径を下記評価ランクに当てはめて、負極用組成物の分散性を評価した。結果を後記表２に示す。
 
－評価ランク－
　３：平均粒径１０μｍ以上、３０μｍ未満
　２：平均粒径３０μｍ以上、５０μｍ未満
　１：平均粒径５０μｍ以上、７０μｍ以下 (Evaluation of Dispersibility of Negative Electrode Composition)
Using a grind gauge (manufactured by ERICHSEN, model 232), the solid particles contained in the prepared negative electrode composition (high-capacity active material, active material, conductive aid and polymer particles described in Table 2 below) The average particle diameter (volume-based median diameter D50) was measured. The obtained average particle size was applied to the following evaluation rank to evaluate the dispersibility of the negative electrode composition. The results are shown in Table 2 below.

-Evaluation Rank-
3: Average particle size 10 µm or more and less than 30 µm 2: Average particle size 30 µm or more and less than 50 µm 1: Average particle size 50 µm or more and 70 µm or less
［負極シートの作製１］
　後記表２に記載する負極シート１を作製した。
　具体的には、得られた負極用組成物１を厚み１８μｍ、横９０ｍｍ、縦２４０ｍｍの銅箔上に、アプリケーターにより塗布し、８０℃１時間で乾燥させた。その後、プレス機を用いて、加圧した後に１５０℃真空で６時間乾燥することで、負極活物質層の厚さが２５μｍの負極シート１（横５０～８０ｍｍ、縦１５０～２１０ｍｍ）を得た。 [Preparation of negative electrode sheet 1]
A negative electrode sheet 1 described in Table 2 below was produced.
Specifically, the negative electrode composition 1 thus obtained was applied onto a copper foil having a thickness of 18 μm, a width of 90 mm and a length of 240 mm using an applicator, and dried at 80° C. for 1 hour. Thereafter, using a pressing machine, it was dried at 150° C. in vacuum for 6 hours after pressurization to obtain a negative electrode sheet 1 (50 to 80 mm wide, 150 to 210 mm long) having a thickness of the negative electrode active material layer of 25 μm. .
　負極シート１の作製において、負極用組成物１に代えて後記表２に記載する負極用組成物を採用したこと以外は、負極シート１の作製と同様にして、負極シート２～１１及びｃ１～ｃ５を作製した。 In the production of negative electrode sheet 1, negative electrode sheets 2 to 11 and c1 to 2 were prepared in the same manner as in the production of negative electrode sheet 1, except that the negative electrode composition described in Table 2 below was used instead of negative electrode composition 1. c5 was produced.
（負極活物質層の密着性の評価）
　作製した負極シートから、横１０ｍｍ、縦５０ｍｍの試験片を３枚切り出した。切り出した３枚の試験片の各々の負極活物質層に、粘着テープ（横１０ｍｍ、縦５０ｍｍ、商品名：ナイスタック　ビジネスパック、両面テープ、ニチバン社製）を貼り、この粘着テープを介して、各試験片をガラス板に貼り付けた。ガラス板が下側になるようにして置き、９０°の角度、１００ｍｍ／ｍｉｎの速度で負極活物質層から銅箔（集電体）を引き剥がした際の平均応力を各試験片について測定した。得られた各平均応力の合計を３で割って得られた値（単位：Ｎ）を、下記評価ランクに当てはめて評価した。結果を後記表２に示す。
 
－密着性の評価ランク－
　４：　０．２０Ｎ以上
　３：　０．１２Ｎ以上、０．２０Ｎ未満
　２：　０．０５Ｎ以上、０．１２Ｎ未満
　１：　０．０５Ｎ未満
（評価ランクが高い程、負極活物質層と集電体（銅箔）との密着性が強固である。） (Evaluation of Adhesion of Negative Electrode Active Material Layer)
Three test pieces with a width of 10 mm and a length of 50 mm were cut out from the produced negative electrode sheet. Adhesive tape (10 mm wide, 50 mm long, product name: Nicetac Business Pack, double-sided tape, manufactured by Nichiban Co., Ltd.) is attached to each of the negative electrode active material layers of the three cut test pieces, and through this adhesive tape, Each test piece was attached to a glass plate. Placed with the glass plate facing downward, the average stress was measured for each test piece when the copper foil (current collector) was peeled off from the negative electrode active material layer at an angle of 90° and at a rate of 100 mm/min. . The value (unit: N) obtained by dividing the sum of each average stress obtained by 3 was applied to the following evaluation ranks for evaluation. The results are shown in Table 2 below.

-Adhesion evaluation rank-
4: 0.20 N or more 3: 0.12 N or more and less than 0.20 N 2: 0.05 N or more and less than 0.12 N 1: Less than 0.05 N (the higher the evaluation rank, the more the negative electrode active material layer and the current collector ( (Copper foil) has strong adhesion.)
［非水電解液二次電池（２０３２型コイン電池）の作製１］
　非水電解液二次電池１（後記表２のＮｏ．１の電池）を作製した。
　具体的には、上記負極シートから直径１３．０ｍｍの円板を切り出し、負極の形成に用いた。リチウム箔（厚み５０μｍ、１４．５ｍｍφ）、ポリプロピレン製セパレータ（厚み２５μｍ、１６．０ｍｍφ）の順番に重ねＬｉＰＦ６のエチレンカーボネート／エチルメチルカーボネート（体積比１対２、濃度１Ｍ）電解液を２００μＬセパレータに浸み込ませた。セパレータの上に更に上記電解液を２００μＬ浸み込ませて、負極シートを負極活物質層面がセパレータに接するようにして重ねた。その後、２０３２型コインケースをかしめることで、非水電解液二次電池１（Ｌｉ箔－セパレータ－負極活物質層－銅箔からなる積層体を有する電池）を作製した。 [Preparation of non-aqueous electrolyte secondary battery (2032 type coin battery) 1]
A non-aqueous electrolyte secondary battery 1 (No. 1 battery in Table 2 below) was produced.
Specifically, a disk with a diameter of 13.0 mm was cut out from the negative electrode sheet and used to form the negative electrode. Lithium foil (thickness 50 μm , 14.5 mmφ) and polypropylene separator (thickness 25 μm, 16.0 mmφ) are stacked in this order. soaked in. 200 μL of the electrolytic solution was further impregnated on the separator, and the negative electrode sheet was stacked so that the negative electrode active material layer surface was in contact with the separator. After that, the 2032 type coin case was crimped to prepare a non-aqueous electrolyte secondary battery 1 (a battery having a laminate consisting of Li foil-separator-negative electrode active material layer-copper foil).
　非水電解液二次電池１の作製において、後記表２に記載する負極用組成物（負極シート）を採用したこと以外は、非水電解液二次電池１の作製と同様にして、非水電解液二次電池２～１１及びｃ１～ｃ５（後記表２のＮｏ．２～１１及びｃ１～ｃ５の電池）を作製した。 In the production of the non-aqueous electrolyte secondary battery 1, a non-aqueous Electrolyte secondary batteries 2 to 11 and c1 to c5 (batteries Nos. 2 to 11 and c1 to c5 in Table 2 below) were produced.
［試験例１］　サイクル特性の評価
　各コイン電池の放電容量維持率を、充放電評価装置：ＴＯＳＣＡＴ－３０００（商品名、東洋システム社製）により測定した。充電は、Ｃレート（Ｃａｐａｃｉｔｙレート）０．２Ｃ（５時間で満充電になる速度）で電池電圧が０．０２Ｖに達するまで行った。放電は、Ｃレート０．２Ｃで電池電圧が１．５Ｖに達するまで行った。この充電１回と放電１回とを充放電１サイクルとして３サイクル充放電を繰り返して、各コイン電池を初期化した。
　初期化後、充電を０．５Ｃで０．０２Ｖに達するまで行った。放電を０．５Ｃで１．５Ｖに達するまで行った。この充電１回と放電１回を充放電１サイクルとして、８０サイクル充放電を繰り返すことでサイクル特性の評価を行った。
　初期化後１サイクル目の放電容量（初期放電容量）を１００％としたとき、８０サイクル目の放電容量維持率（１００×「８０サイクル目の放電容量」／「初期放電容量」）を算出し、下記評価ランクに当てはめサイクル特性を評価した。結果を後記表２に記載する。
 
－放電容量維持率の評価ランク－
　６：　９０％以上
　５：　８５％以上、９０％未満
　４：　８０％以上、８５％未満
　３：　７０％以上、８０％未満
　２：　５０％以上、７０％未満
　１：　５０％未満 [Test Example 1] Evaluation of Cycle Characteristics The discharge capacity retention rate of each coin battery was measured with a charge/discharge evaluation device: TOSCAT-3000 (trade name, manufactured by Toyo System Co., Ltd.). The battery was charged at a C rate (capacity rate) of 0.2C (the rate at which the battery is fully charged in 5 hours) until the battery voltage reached 0.02V. Discharge was performed at a C rate of 0.2C until the battery voltage reached 1.5V. Each coin battery was initialized by repeating 3 cycles of charging and discharging, with one charging and one discharging as one charging and discharging cycle.
After initialization, charging was performed at 0.5C until reaching 0.02V. Discharge was performed at 0.5C until reaching 1.5V. Cycle characteristics were evaluated by repeating 80 charge/discharge cycles, with one charge/discharge cycle as one charge/discharge cycle.
Assuming that the discharge capacity at the first cycle after initialization (initial discharge capacity) is 100%, the discharge capacity retention rate at the 80th cycle (100 × “80th cycle discharge capacity” / “initial discharge capacity”) was calculated. , was applied to the following evaluation ranks, and the cycle characteristics were evaluated. The results are shown in Table 2 below.

-Evaluation rank of discharge capacity retention rate-
6: 90% or more 5: 85% or more and less than 90% 4: 80% or more and less than 85% 3: 70% or more and less than 80% 2: 50% or more and less than 70% 1: less than 50%
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
＜表２の注＞
ＳｉＯＣ：カーボンコートされた酸化ケイ素（炭素元素の含有量の割合１．３質量％、平均粒径：５μｍ、大阪チタニウムテクノロジーズ社製）
黒鉛：ＭＡＧ－Ｄ（商品名、昭和電工マテリアルズ社製）
ＡＢ：アセチレンブラック（商品名：デンカブラック、デンカ社製）
ＰＡＡｍ、ＡＡｍ／ＡＡ（９７／３）等の水溶性高分子（Ｘ）、ＣＭＣ、ＳＲ－１５１等の重合体粒子：＜表１の注＞を参照
含有量（％）：負極用組成物に含まれる各成分（固形分）の合計に占める各成分（固形分）の割合を質量基準で示したものである（表２中の「％」は「質量％」を意味する。）。なお、負極用組成物Ｎｏ．１～１１、ｃ１～ｃ５において、高容量活物質の欄に記載のＳｉＯＣの含有量は１７．８質量％、活物質の欄に記載の黒鉛の含有量は７１．２質量％、導電助剤の欄に記載のＡＢの含有量は６．００質量％であり、上記表中では、これらの記載を省略している。
引張弾性率の比の値：水溶性高分子（Ｘ）の引張弾性率／重合体粒子の引張弾性率。表１に記載の引張弾性率の値に基づき算出した値である。 <Note to Table 2>
SiOC: carbon-coated silicon oxide (content ratio of carbon element: 1.3% by mass, average particle size: 5 μm, manufactured by Osaka Titanium Technologies Co., Ltd.)
Graphite: MAG-D (trade name, manufactured by Showa Denko Materials)
AB: Acetylene black (trade name: Denka Black, manufactured by Denka)
Water-soluble polymer (X) such as PAAm, AAm/AA (97/3), CMC, polymer particles such as SR-151: see <Notes in Table 1> Content (%): in the negative electrode composition The ratio of each component (solid content) to the total of each component (solid content) contained is shown on a mass basis (“%” in Table 2 means “% by mass”). In addition, negative electrode composition No. 1 to 11 and c1 to c5, the content of SiOC described in the column of high-capacity active material is 17.8% by mass, the content of graphite described in the column of active material is 71.2% by mass, and the conductive aid is 6.00% by mass, and these descriptions are omitted in the above table.
Value of ratio of tensile modulus: tensile modulus of water-soluble polymer (X)/tensile modulus of polymer particles. It is a value calculated based on the value of the tensile modulus described in Table 1.
　表２から以下のことが分かる。
　Ｎｏ．ｃ１の負極用組成物は、水溶性高分子（Ｙ）及び重合体粒子を用いずに調製した。Ｎｏ．ｃ１の負極用組成物を用いて作製したＮｏ．ｃ１の負極シートは密着性が劣った。
　Ｎｏ．ｃ２の負極用組成物は、重合体粒子を用いずに調製した。Ｎｏ．ｃ２の負極用組成物を用いて作製したＮｏ．ｃ２の負極シートは密着性が劣った。
　Ｎｏ．ｃ３の負極用組成物は、水溶性高分子（Ｙ）を用いずに調製した。Ｎｏ．ｃ３の負極用組成物は分散性が低く、この組成物を用いて作製したＮｏ．ｃ３の負極シートは密着性が不十分であった。また、上記組成物を用いて作製したＮｏ．ｃ３の二次電池はサイクル特性が劣った。
　Ｎｏ．ｃ４及び５の負極用組成物は、「引張弾性率の比の値」が本発明の規定を満たさない水溶性高分子（Ｘ）及び重合体粒子を用いて調製した。Ｎｏ．ｃ４及び５の負極用組成物を用いて作製したＮｏ．ｃ４及び５の二次電池はサイクル特性が劣った。
　これに対して、本発明の負極用組成物（Ｎｏ．１～１１）を用いて作製した本発明の負極シート（Ｎｏ．１～１１）は密着性が優れることが分かる。本発明の負極用組成物（Ｎｏ．１～１１）を用いて作製した本発明の二次電池（Ｎｏ．１～１１）はサイクル特性が優れることが分かる。 Table 2 reveals the following.
No. The negative electrode composition c1 was prepared without using the water-soluble polymer (Y) and polymer particles. No. No. c1 produced using the negative electrode composition. The negative electrode sheet of c1 was inferior in adhesion.
No. The negative electrode composition of c2 was prepared without using polymer particles. No. No. c2 produced using the negative electrode composition. The negative electrode sheet of c2 had poor adhesion.
No. The negative electrode composition c3 was prepared without using the water-soluble polymer (Y). No. The negative electrode composition of c3 has low dispersibility, and No. c3 produced using this composition. The negative electrode sheet of c3 had insufficient adhesion. In addition, No. 1 produced using the above composition. The c3 secondary battery was inferior in cycle characteristics.
No. The negative electrode compositions c4 and 5 were prepared using the water-soluble polymer (X) and polymer particles whose "ratio of tensile elastic moduli" did not meet the requirements of the present invention. No. Nos. c4 and 5 prepared using the negative electrode compositions. The secondary batteries of c4 and 5 were inferior in cycle characteristics.
On the other hand, it can be seen that the negative electrode sheets (Nos. 1 to 11) of the present invention produced using the negative electrode compositions (Nos. 1 to 11) of the present invention have excellent adhesion. It can be seen that the secondary batteries (Nos. 1 to 11) of the present invention produced using the negative electrode compositions (Nos. 1 to 11) of the present invention have excellent cycle characteristics.
［金属元素のドープ及びカーボンコートの両方が施された活物質の作製］
（１）リチウムドープ及びカーボンコートの両方が施された酸化ケイ素の作製
　特開２０２２－１２１５８２号公報の実施例１－１に記載の方法と同様にして、リチウムドープ及びカーボンコートの両方が施された酸化ケイ素（ＬｉＳｉＯＣ）を作製した。具体的には以下のようにして行った。
　金属ケイ素と二酸化ケイ素を混合した原料（気化出発材）を反応炉へ設置し、１０Ｐａの真空度の雰囲気中で気化させたものを吸着板上に堆積させ、十分に冷却した後、堆積物（酸化ケイ素）を取出しボールミルで粉砕した。粒径を調整した後、熱ＣＶＤ（ｔｈｅｍａｌ　ｃｈｅｍｉｃａｌ　ｖａｐｏｒ　ｄｅｐｏｓｉｔｉｏｎ）を行うことでカーボンコートを形成した。熱ＣＶＤの際には、粉砕した酸化ケイ素を、窒化珪素製トレイに仕込んだ後、雰囲気を保持できる処理炉内に静置した。次にアルゴンガスを流入し、処理炉内をアルゴン置換した後、メタン－アルゴン混合ガスを２ＮＬ／ｍｉｎ流入しつつ３００℃／ｈｒの昇温速度で昇温し、６００～１，１００℃の温度で、３～１０時間保持することにより熱ＣＶＤを施し、カーボンコートされた酸化ケイ素（ＳｉＯＣ）を得た。保持終了後、降温を開始し、室温到達後、粉末を回収した。
　続いて、カーボンコートされた酸化ケイ素に対して酸化還元法によりリチウムをドープし改質を行った。まず、カーボンコートされた酸化ケイ素を、リチウム片とナフタレンとをテトラヒドロフラン（以下、ＴＨＦと呼称する）に溶解させた溶液（溶液Ａ）に浸漬した。この溶液Ａは、具体的には、ＴＨＦ溶媒にナフタレンを０．２ｍｏｌ／Ｌの濃度で溶解させたのちに、このＴＨＦ溶媒とナフタレンとの混合液に対して１０質量％の質量分のリチウム片を加えることで作製した。また、カーボンコートされた酸化ケイ素を浸漬する際の溶液Ａの温度は２０℃とし、浸漬時間は２０時間とした。その後、固形分を濾取した。以上の処理によりカーボンコートされた酸化ケイ素にリチウムをドープした。得られた固形分をアルゴン雰囲気下６００℃で２４時間熱処理を行い、Ｌｉ化合物の安定化を行った。このようにして、カーボンコートされた酸化ケイ素の改質を行い、リチウムドープ及びカーボンコートの両方が施された酸化ケイ素（ＬｉＳｉＯＣ）を得た。なお、炭素元素の含有量の割合は３質量％、ＬｉＳｉＯＣ粒子の平均粒径（体積基準のメジアン径Ｄ５０）は６．７μｍであった。 [Preparation of active material with both metal element doping and carbon coating]
(1) Preparation of silicon oxide both lithium-doped and carbon-coated Both lithium-doped and carbon-coated in the same manner as the method described in Example 1-1 of JP-A-2022-121582. A silicon oxide (LiSiOC) was prepared. Specifically, it was carried out as follows.
A raw material (vaporization starting material) in which metal silicon and silicon dioxide are mixed is placed in a reaction furnace, vaporized in a vacuum atmosphere of 10 Pa, deposited on an adsorption plate, cooled sufficiently, and deposited ( Silicon oxide) was taken out and pulverized with a ball mill. After adjusting the particle size, a carbon coat was formed by thermal CVD (thermal chemical vapor deposition). During the thermal CVD, the pulverized silicon oxide was placed in a silicon nitride tray and then placed in a processing furnace capable of maintaining an atmosphere. Next, after argon gas was introduced to replace the inside of the treatment furnace with argon, the temperature was raised at a temperature elevation rate of 300°C/hr while introducing a methane-argon mixed gas at 2 NL/min to reach a temperature of 600 to 1,100°C. and held for 3 to 10 hours to perform thermal CVD to obtain carbon-coated silicon oxide (SiOC). After the end of holding, the temperature was started to drop, and after reaching room temperature, the powder was collected.
Subsequently, the carbon-coated silicon oxide was doped with lithium by an oxidation-reduction method for modification. First, the carbon-coated silicon oxide was immersed in a solution (solution A) in which lithium pieces and naphthalene were dissolved in tetrahydrofuran (hereinafter referred to as THF). Specifically, this solution A is obtained by dissolving naphthalene in a THF solvent at a concentration of 0.2 mol/L, and then adding 10% by mass of lithium pieces to the mixed solution of this THF solvent and naphthalene. It was made by adding Further, the temperature of the solution A when the carbon-coated silicon oxide was immersed was set to 20° C., and the immersion time was set to 20 hours. After that, the solid content was collected by filtration. Lithium was doped into the carbon-coated silicon oxide by the above treatment. The obtained solid content was heat-treated at 600° C. for 24 hours in an argon atmosphere to stabilize the Li compound. In this manner, the carbon-coated silicon oxide was modified to obtain silicon oxide (LiSiOC) that was both lithium-doped and carbon-coated. The carbon element content was 3% by mass, and the LiSiOC particles had an average particle diameter (volume-based median diameter D50) of 6.7 μm.
（２）ニッケルドープ及びカーボンコートの両方が施された酸化ケイ素、並びにチタンドープ及びカーボンコートの両方が施された酸化ケイ素の作製
　特開２０２１－１５００７７号公報の実施例に記載の負極用粉末材料の作製と同様にして、ニッケルドープ及びカーボンコートの両方が施された酸化ケイ素（ＮｉＳｉＯＣ）並びにチタンドープ及びカーボンコートの両方が施された酸化ケイ素（ＴｉＳｉＯＣ）を作製した。具体的には以下のようにして行った。
（ｉ）Ｓｉ合金の作製
　後記表Ａに示すＳｉ合金組成となるように各原料を秤量した。秤量した各原料を高周波誘導炉を用いて加熱、溶解し、合金溶湯とした。ガスアトマイズ法により、上記得られた合金溶湯から粉末状のＳｉ合金を作製した。なお、合金溶湯作製時およびガスアトマイズ時の雰囲気はアルゴン雰囲気とした。また、ガスアトマイズ時には、噴霧チャンバ内を棒状に落下する合金溶湯に対して、高圧（４ＭＰａ）のアルゴンガスを噴き付けた。得られた粉末を篩いを用いて２５μｍ以下に分級したものを、以降のステップでＳｉ合金として用いた。
（ii）メカニカルミリング処理の準備
　ステンレス製のポット中に、金属ボール（サイズ：Φ３／８ｉｎｃｈ、材質：ＳＵＪ２（ＪＩＳ（日本工業規格）　Ｇ　４８０５（２０１９）規定の高炭素クロム軸受鋼鋼材ＳＵＪ２））３０個とともに、後記表Ａに示す混合割合となるように、Ｓｉ合金と、金属酸化物としてのＳｉＯ２粉末とを投入した。例えば目的物を１０ｇ作製する場合、Ｓｉ合金９．５ｇとＳｉＯ２粉末０．５ｇとを投入した。投入後、ポット内部の雰囲気をＡｒガスで置換した。
（iii）メカニカルミリング処理
　ポットを遊星ボールミル装置（フリッチュ社製、Ｐ－５／４）にセットし、３００ｒｐｍ、１５０時間の条件で処理して得られた混合粉末を、以降のステップで金属元素をドープされたケイ素系材料（ニッケルドープされた酸化ケイ素（ＮｉＳｉＯ）又はチタンドープされた酸化ケイ素（ＴｉＳｉＯ））として用いた。
（iv）金属元素をドープされたケイ素系材料へのカーボンコート処理
　金属元素をドープされたケイ素系材料（ＮｉＳｉＯ又はＴｉＳｉＯ）に、熱ＣＶＤを行うことでカーボンコートを形成した。熱ＣＶＤの際には、メカニカルミリング処理後の金属元素をドープされたケイ素系材料を、窒化珪素製トレイに仕込んだ後、雰囲気を保持できる処理炉内に静置した。次にアルゴンガスを流入し、処理炉内をアルゴン置換した後、メタン－アルゴン混合ガスを２ＮＬ／ｍｉｎ流入しつつ３００℃／ｈｒの昇温速度で昇温し、６００～１，１００℃の温度で、３～１０時間保持することにより炭素膜の熱ＣＶＤを施し、金属元素のドープ及びカーボンコートの両方が施されたケイ素系材料（ニッケルドープ及びカーボンコートの両方が施された酸化ケイ素（ＮｉＳｉＯＣ）並びにチタンドープ及びカーボンコートの両方が施された酸化ケイ素（ＴｉＳｉＯＣ））を得た。保持終了後、降温を開始し、室温到達後、粉末を回収した。
　なお、炭素元素の含有量の割合は３質量％、ＮｉＳｉＯＣ粒子及びＴｉＳｉＯＣ粒子の平均粒径（体積基準のメジアン径Ｄ５０）は共に７μｍであった。 (2) Preparation of both nickel-doped and carbon-coated silicon oxide and titanium-doped and carbon-coated silicon oxide Powder material for negative electrode described in Examples of JP-A-2021-150077 Both nickel-doped and carbon-coated silicon oxide (NiSiOC) and titanium-doped and carbon-coated silicon oxide (TiSiOC) were prepared in the same manner as in . Specifically, it was carried out as follows.
(i) Preparation of Si alloy Each raw material was weighed so as to obtain the Si alloy composition shown in Table A below. Each weighed raw material was heated and melted using a high-frequency induction furnace to obtain a molten alloy. A powdery Si alloy was produced from the molten alloy obtained above by a gas atomization method. An argon atmosphere was used as the atmosphere during the production of the molten alloy and the gas atomization. Further, at the time of gas atomization, high-pressure (4 MPa) argon gas was sprayed onto the molten alloy falling like a rod in the atomization chamber. The obtained powder was sieved to a size of 25 μm or less and used as the Si alloy in the subsequent steps.
(ii) Preparation for mechanical milling Metal balls (size: Φ3/8 inch, material: SUJ2 (JIS (Japanese Industrial Standards) G 4805 (2019) regulated high-carbon chromium bearing steel SUJ2)) Along with the 30 pieces, a Si alloy and SiO 2 powder as a metal oxide were added so as to have a mixing ratio shown in Table A below. For example, 9.5 g of Si alloy and 0.5 g of SiO 2 powder were added to produce 10 g of the object. After charging, the atmosphere inside the pot was replaced with Ar gas.
(iii) Mechanical milling treatment The pot was set in a planetary ball mill (manufactured by Fritsch, P-5/4), and the mixed powder obtained by treatment under the conditions of 300 rpm and 150 hours was treated with metal elements in the subsequent steps. It was used as a doped silicon-based material (nickel-doped silicon oxide (NiSiO) or titanium-doped silicon oxide (TiSiO)).
(iv) Carbon coating treatment on silicon-based material doped with metal element A carbon coat was formed by thermal CVD on the silicon-based material (NiSiO or TiSiO) doped with a metal element. During the thermal CVD, the silicon-based material doped with the metal element after the mechanical milling treatment was placed in a silicon nitride tray, and then placed in a treatment furnace capable of holding an atmosphere. Next, after argon gas was introduced to replace the inside of the treatment furnace with argon, the temperature was raised at a temperature elevation rate of 300°C/hr while introducing a methane-argon mixed gas at 2 NL/min to reach a temperature of 600 to 1,100°C. , the carbon film is subjected to thermal CVD by holding for 3 to 10 hours, and a silicon-based material with both metal element doping and carbon coating (silicon oxide with both nickel doping and carbon coating (NiSiOC ) and both titanium-doped and carbon-coated silicon oxide (TiSiOC)). After the end of holding, the temperature was started to drop, and after reaching room temperature, the powder was recovered.
The carbon element content was 3% by mass, and the average particle diameter (volume-based median diameter D50) of the NiSiOC particles and the TiSiOC particles was both 7 μm.
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
＜表Ａの注＞
ＮｉＳｉＯ：ニッケルドープされた酸化ケイ素
ＴｉＳｉＯ：チタンドープされた酸化ケイ素
合金組成：金属元素をドープされたケイ素系材料（ＮｉＳｉＯ又はＴｉＳｉＯ）を得る際に投入したＳｉ合金及びＳｉＯ２粉末の合計１００質量％に占めるＳｉ合金中の各金属元素の割合を示し、単位は質量％であり、合金組成の合計は９５質量％である。
混合割合：金属元素をドープされたケイ素系材料（ＮｉＳｉＯ又はＴｉＳｉＯ）を得る際に投入したＳｉ合金及びＳｉＯ２粉末の合計に占める各成分（Ｓｉ合金又はＳｉＯ２粉末）の割合を示し、単位は質量％である。 <Note to Table A>
NiSiO: nickel-doped silicon oxide TiSiO: titanium-doped silicon oxide alloy Composition: total 100% by weight of Si alloy and SiO2 powder introduced in obtaining silicon-based material doped with metal elements (NiSiO or TiSiO) The ratio of each metal element in the Si alloy to the total of the alloy composition is 95% by mass.
Mixing ratio: Indicates the ratio of each component (Si alloy or SiO2 powder) to the total of Si alloy and SiO2 powder introduced when obtaining a silicon-based material (NiSiO or TiSiO) doped with a metal element, and the unit is % by mass.
［負極用組成物の調製２］
　上述の［負極用組成物の調製１］において、上記表２に記載の負極用組成物１～１１及びｃ１～ｃ５中の高容量活物質を、カーボンコートされた酸化ケイ素（ＳｉＯＣ）から（Ａ）リチウムドープ及びカーボンコートの両方が施された酸化ケイ素（ＬｉＳｉＯＣ）、（Ｂ）ニッケルドープ及びカーボンコートの両方が施された酸化ケイ素（ＮｉＳｉＯＣ）、又は（Ｃ）チタンドープ及びカーボンコートの両方が施された酸化ケイ素（ＴｉＳｉＯＣ）に変更した以外は、上述の［負極用組成物の調製１］と同様にして、負極用組成物１－Ａ～１１－Ａ及びｃ１－Ａ～ｃ５－Ａ、負極用組成物１－Ｂ～１１－Ｂ及びｃ１－Ｂ～ｃ５－Ｂ、並びに負極用組成物１－Ｃ～１１－Ｃ及びｃ１－Ｃ～ｃ５－Ｃをそれぞれ調製した。 [Preparation of negative electrode composition 2]
In the above [Preparation of negative electrode composition 1], the high-capacity active materials in the negative electrode compositions 1 to 11 and c1 to c5 described in Table 2 above are carbon-coated silicon oxide (SiOC) (A (B) both nickel-doped and carbon-coated silicon oxide (NiSiOC); or (C) both titanium-doped and carbon-coated. Negative electrode compositions 1-A to 11-A and c1-A to c5-A, c1-A to c5-A, and Negative electrode compositions 1-B to 11-B and c1-B to c5-B, and negative electrode compositions 1-C to 11-C and c1-C to c5-C were prepared, respectively.
（負極用組成物の分散性の評価）
　グラインドゲージ（ＥＲＩＣＨＳＥＮ社製、モデル２３２）を用いて、調製した負極用組成物に含まれる固体粒子（高容量活物質、活物質、導電助剤及び重合体粒子の全体）の平均粒径（体積基準のメジアン径Ｄ５０）を測定した。得られた平均粒径を下記評価ランクに当てはめて、負極用組成物の分散性を評価した。結果を後記表３－Ａ、表３－Ｂ及び表３－Ｃに示す。以下、後記表３－Ａ、表３－Ｂ及び表３－Ｃをまとめて表３と称する。
 
－評価ランク－
　３：平均粒径１０μｍ以上、３０μｍ未満
　２：平均粒径３０μｍ以上、５０μｍ未満
　１：平均粒径５０μｍ以上、７０μｍ以下 (Evaluation of Dispersibility of Negative Electrode Composition)
Using a grind gauge (manufactured by ERICHSEN, model 232), the average particle size (volume A standard median diameter D50) was measured. The obtained average particle size was applied to the following evaluation rank to evaluate the dispersibility of the negative electrode composition. The results are shown in Tables 3-A, 3-B and 3-C below. Hereinafter, Tables 3-A, 3-B, and 3-C are collectively referred to as Table 3.

-Evaluation Rank-
3: Average particle size 10 µm or more and less than 30 µm 2: Average particle size 30 µm or more and less than 50 µm 1: Average particle size 50 µm or more and 70 µm or less
［負極シートの作製２］
　上述の［負極シートの作製１］において、上記表２に記載の負極用組成物１～１１及びｃ１～ｃ５に代えて、後記表３に記載する負極用組成物を採用したこと以外は、上述の［負極シートの作製１］と同様にして、負極シート１－Ａ～１１－Ａ及びｃ１－Ａ～ｃ５－Ａ、負極シート１－Ｂ～１１－Ｂ及びｃ１－Ｂ～ｃ５－Ｂ、並びに負極シート１－Ｃ～１１－Ｃ及びｃ１－Ｃ～ｃ５－Ｃをそれぞれ作製した。 [Preparation of negative electrode sheet 2]
In [Preparation of Negative Electrode Sheet 1] described above, instead of the negative electrode compositions 1 to 11 and c1 to c5 described in Table 2, the negative electrode compositions described in Table 3 below were used. In the same manner as in [Preparation of negative electrode sheet 1], negative electrode sheets 1-A to 11-A and c1-A to c5-A, negative electrode sheets 1-B to 11-B and c1-B to c5-B, and Negative electrode sheets 1-C to 11-C and c1-C to c5-C were prepared, respectively.
（負極活物質層の密着性の評価）
　作製した負極シートから、横１０ｍｍ、縦５０ｍｍの試験片を３枚切り出した。切り出した３枚の試験片の各々の負極活物質層に、粘着テープ（横１０ｍｍ、縦５０ｍｍ、商品名：ナイスタック　ビジネスパック、両面テープ、ニチバン社製）を貼り、この粘着テープを介して、各試験片をガラス板に貼り付けた。ガラス板が下側になるようにして置き、９０°の角度、１００ｍｍ／ｍｉｎの速度で負極活物質層から銅箔（集電体）を引き剥がした際の平均応力を各試験片について測定した。得られた各平均応力の合計を３で割って得られた値（単位：Ｎ）を、下記評価ランクに当てはめて評価した。結果を後記表３に示す。
 
－密着性の評価ランク－
　４：　０．２０Ｎ以上
　３：　０．１２Ｎ以上、０．２０Ｎ未満
　２：　０．０５Ｎ以上、０．１２Ｎ未満
　１：　０．０５Ｎ未満
（評価ランクが高い程、負極活物質層と集電体（銅箔）との密着性が強固である。） (Evaluation of Adhesion of Negative Electrode Active Material Layer)
Three test pieces with a width of 10 mm and a length of 50 mm were cut out from the produced negative electrode sheet. Adhesive tape (10 mm wide, 50 mm long, product name: Nicetac Business Pack, double-sided tape, manufactured by Nichiban Co., Ltd.) is attached to each of the negative electrode active material layers of the three cut test pieces, and through this adhesive tape, Each test piece was attached to a glass plate. Placed with the glass plate facing downward, the average stress was measured for each test piece when the copper foil (current collector) was peeled off from the negative electrode active material layer at an angle of 90° and at a rate of 100 mm/min. . A value (unit: N) obtained by dividing the sum of each average stress obtained by 3 was applied to the following evaluation rank and evaluated. The results are shown in Table 3 below.

-Adhesion evaluation rank-
4: 0.20 N or more 3: 0.12 N or more and less than 0.20 N 2: 0.05 N or more and less than 0.12 N 1: Less than 0.05 N (the higher the evaluation rank, the more the negative electrode active material layer and the current collector ( (Copper foil) has strong adhesion.)
［非水電解液二次電池（２０３２型コイン電池）の作製２］
　上述の［非水電解液二次電池（２０３２型コイン電池）の作製１］において、上記表２に記載の負極用組成物１～１１及びｃ１～ｃ５に代えて、後記表３に記載する負極用組成物を採用したこと以外は、上述の［非水電解液二次電池（２０３２型コイン電池）の作製１］と同様にして、非水電解液二次電池１－Ａ～１１－Ａ及びｃ１－Ａ～ｃ５－Ａ、非水電解液二次電池１－Ｂ～１１－Ｂ及びｃ１－Ｂ～ｃ５－Ｂ、並びに非水電解液二次電池１－Ｃ～１１－Ｃ及びｃ１－Ｃ～ｃ５－Ｃ（後記表３のＮｏ．１－Ａ～１１－Ａ及びｃ１－Ａ～ｃ５－Ａの電池、Ｎｏ．１－Ｂ～１１－Ｂ及びｃ１－Ｂ～ｃ５－Ｂの電池、並びにＮｏ．１－Ｃ～１１－Ｃ及びｃ１－Ｃ～ｃ５－Ｃの電池）をそれぞれ作製した。 [Preparation of non-aqueous electrolyte secondary battery (2032 type coin battery) 2]
In the above [Preparation of non-aqueous electrolyte secondary battery (2032 type coin battery) 1], instead of the negative electrode compositions 1 to 11 and c1 to c5 described in Table 2 above, the negative electrode described in Table 3 below Non-aqueous electrolyte secondary batteries 1-A to 11-A and non-aqueous electrolyte secondary batteries 1-A to 11-A and c1-A to c5-A, non-aqueous electrolyte secondary batteries 1-B to 11-B and c1-B to c5-B, and non-aqueous electrolyte secondary batteries 1-C to 11-C and c1-C ~ c5-C (No. 1-A to 11-A and c1-A to c5-A batteries in Table 3 below, No. 1-B to 11-B and c1-B to c5-B batteries, and No. 1-C to 11-C and c1-C to c5-C batteries) were produced respectively.
［試験例２］　サイクル特性の評価
　上述の［試験例１］と同様にして各コイン電池の放電容量維持率を測定し、初期化後１サイクル目の放電容量（初期放電容量）を１００％としたときの、８０サイクル目の放電容量維持率（１００×「８０サイクル目の放電容量」／「初期放電容量」）を算出し、下記評価ランクに当てはめサイクル特性を評価した。結果を後記表３に記載する。
 
－放電容量維持率の評価ランク－
　６：　９０％以上
　５：　８５％以上、９０％未満
　４：　８０％以上、８５％未満
　３：　７０％以上、８０％未満
　２：　５０％以上、７０％未満
　１：　５０％未満 [Test Example 2] Evaluation of cycle characteristics The discharge capacity retention rate of each coin battery was measured in the same manner as in [Test Example 1] described above, and the discharge capacity at the first cycle after initialization (initial discharge capacity) was taken as 100%. Then, the discharge capacity retention rate at the 80th cycle (100ד80th cycle discharge capacity”/“initial discharge capacity”) was calculated and applied to the following evaluation rank to evaluate the cycle characteristics. The results are shown in Table 3 below.

-Evaluation rank of discharge capacity retention rate-
6: 90% or more 5: 85% or more and less than 90% 4: 80% or more and less than 85% 3: 70% or more and less than 80% 2: 50% or more and less than 70% 1: less than 50%
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000011
＜表３の注＞
　表３－Ａ：上記表２に記載の負極用組成物、負極シート及び電池１～１１及びｃ１～ｃ５中の高容量活物質であるカーボンコートされた酸化ケイ素（ＳｉＯＣ）をリチウムドープ及びカーボンコートの両方が施された酸化ケイ素（ＬｉＳｉＯＣ）に変更した、負極用組成物、負極シート及び電池１－Ａ～１１－Ａ及びｃ１－Ａ～ｃ５－Ａに係る評価を記載する。
　表３－Ｂ：上記表２に記載の負極用組成物、負極シート及び電池１～１１及びｃ１～ｃ５中の高容量活物質であるカーボンコートされた酸化ケイ素（ＳｉＯＣ）をニッケルドープ及びカーボンコートの両方が施された酸化ケイ素（ＮｉＳｉＯＣ）に変更した、負極用組成物、負極シート及び電池１－Ｂ～１１－Ｂ及びｃ１－Ｂ～ｃ５－Ｂに係る評価を記載する。
　表３－Ｃ：上記表２に記載の負極用組成物、負極シート及び電池１～１１及びｃ１～ｃ５中の高容量活物質であるカーボンコートされた酸化ケイ素（ＳｉＯＣ）をチタンドープ及びカーボンコートの両方が施された酸化ケイ素（ＴｉＳｉＯＣ）に変更した、負極用組成物、負極シート及び電池１－Ｃ～１１－Ｃ及びｃ１－Ｃ～ｃ５－Ｃに係る評価を記載する。 <Note to Table 3>
Table 3-A: Lithium-doped and carbon-coated carbon-coated silicon oxide (SiOC), which is a high-capacity active material in the negative electrode composition, negative electrode sheet, and batteries 1 to 11 and c1 to c5 described in Table 2 above. Evaluations of negative electrode compositions, negative electrode sheets, and batteries 1-A to 11-A and c1-A to c5-A, which are changed to silicon oxide (LiSiOC) to which both of are applied, are described.
Table 3-B: Ni-doped and carbon-coated carbon-coated silicon oxide (SiOC), which is a high-capacity active material in the negative electrode composition, negative electrode sheet, and batteries 1 to 11 and c1 to c5 described in Table 2 above. Evaluations of negative electrode compositions, negative electrode sheets, and batteries 1-B to 11-B and c1-B to c5-B, which were changed to silicon oxide (NiSiOC) subjected to both of the above, are described.
Table 3-C: Carbon-coated silicon oxide (SiOC), which is a high-capacity active material in the negative electrode composition, negative electrode sheet, and batteries 1 to 11 and c1 to c5 described in Table 2 above, is titanium-doped and carbon-coated. Evaluations of negative electrode compositions, negative electrode sheets, and batteries 1-C to 11-C and c1-C to c5-C, which are changed to silicon oxide (TiSiOC) to which both are applied, are described.
　表３から以下のことがわかる。
　高容量活物質として、カーボンコートされた酸化ケイ素（ＳｉＯＣ）に代えて、リチウムドープ及びカーボンコートの両方が施された酸化ケイ素（ＬｉＳｉＯＣ）、ニッケルドープ及びカーボンコートの両方が施された酸化ケイ素（ＮｉＳｉＯＣ）、又はチタンドープ及びカーボンコートの両方が施された酸化ケイ素（ＴｉＳｉＯＣ）のいずれを用いた場合においても、各負極用組成物の分散性は、表２の高容量活物質がカーボンコートされた酸化ケイ素（ＳｉＯＣ）である点以外は同じ組成である、対応する負極用組成物の分散性と同様の傾向を示すことが分かった。また、各負極用組成物を用いて作製した負極シートの密着性、及び各負極用組成物を用いて作製した二次電池のサイクル特性においても、表２の高容量活物質がカーボンコートされた酸化ケイ素（ＳｉＯＣ）である点以外は同じ組成である、対応する負極シートの密着性及び二次電池のサイクル特性と同様の傾向を示すことが分かった。 Table 3 shows the following.
As high-capacity active materials, instead of carbon-coated silicon oxide (SiOC), both lithium-doped and carbon-coated silicon oxide (LiSiOC), nickel-doped and carbon-coated silicon oxide ( NiSiOC) or both titanium-doped and carbon-coated silicon oxide (TiSiOC). It was found that the dispersibility of the corresponding negative electrode composition, which has the same composition except that it is silicon oxide (SiOC), exhibits the same tendency as that of the corresponding negative electrode composition. In addition, the adhesion of the negative electrode sheet prepared using each negative electrode composition and the cycle characteristics of the secondary battery prepared using each negative electrode composition were also evaluated when the high-capacity active material in Table 2 was carbon-coated. It was found that the adhesion and cycle characteristics of the corresponding negative electrode sheet, which has the same composition except that it is silicon oxide (SiOC), show similar tendencies to those of the secondary battery.
　本発明をその実施態様とともに説明したが、我々は特に指定しない限り我々の発明を説明のどの細部においても限定しようとするものではなく、添付の請求の範囲に示した発明の精神と範囲に反することなく幅広く解釈されるべきであると考える。 While we have described our invention in conjunction with embodiments thereof, we do not intend to limit our invention in any detail to the description unless specified otherwise, which is contrary to the spirit and scope of the invention as set forth in the appended claims. I think it should be interpreted broadly.
　本願は、２０２１年１２月２１日に日本国で特許出願された特願２０２１－２０７４１７及び２０２２年３月３０日に日本国で特許出願された特願２０２２－０５６０６４に基づく優先権を主張するものであり、これらはここに参照してその内容を本明細書の記載の一部として取り込む。 This application claims priority based on Japanese Patent Application No. 2021-207417 filed in Japan on December 21, 2021 and Japanese Patent Application No. 2022-056064 filed in Japan on March 30, 2022. , the contents of which are hereby incorporated by reference as part of the present description.
１０　非水電解液二次電池
　１　負極集電体
　２　負極活物質層
　３　セパレータ
　４　正極活物質層
　５　正極集電体
　６　作動部位（電球） REFERENCE SIGNS LIST 10 Nonaqueous electrolyte secondary battery 1 Negative electrode current collector 2 Negative electrode active material layer 3 Separator 4 Positive electrode active material layer 5 Positive electrode current collector 6 Operating part (bulb)

Claims (19)

  1. 　水溶性高分子（Ｘ）、水溶性高分子（Ｙ）及び重合体粒子を含み、
    　前記水溶性高分子（Ｘ）は、下記一般式（Ｂ－１）で表される構成成分及び／又は下記一般式（Ｂ－２）で表される構成成分を含む重合体であり、前記重合体粒子の引張弾性率に対する前記水溶性高分子（Ｘ）の引張弾性率の比の値が１０を超える、二次電池用バインダー組成物。
    Figure JPOXMLDOC01-appb-C000001
     　一般式（Ｂ－１）中、Ｒ１１～Ｒ１３は水素原子、シアノ基又は炭素数１～６のアルキル基を示し、Ｒ１４は水素原子、ヒドロキシ基、炭素数１～６のアルコキシ基、シアノ基、フェニル基、カルボキシ基、スルホ基、リン酸基又はホスホン酸基を示し、Ｌ１１は単結合、炭素数１～１６のアルキレン基、炭素数６～１２のアリーレン基、酸素原子、硫黄原子、カルボニル基若しくはイミノ基、又はこれらを組み合わせた連結基を示す。＊は前記水溶性高分子（Ｘ）の主鎖中に組み込まれるための結合部位を示す。
    　一般式（Ｂ－２）中、Ｒ２１～Ｒ２３は水素原子、シアノ基又は炭素数１～６のアルキル基を示し、Ｒ２４は水素原子、アシル基、ヒドロキシ基、フェニル基又はカルボキシ基を示し、Ｌ２１は単結合、炭素数１～１６のアルキレン基、炭素数６～１２のアリーレン基、酸素原子、硫黄原子、カルボニル基若しくはイミノ基、又はこれらを組み合わせた連結基を示す。＊は前記水溶性高分子（Ｘ）の主鎖中に組み込まれるための結合部位を示す。     Water-soluble polymer (X), water-soluble polymer (Y) and polymer particles,
    The water-soluble polymer (X) is a polymer containing a component represented by the following general formula (B-1) and/or a component represented by the following general formula (B-2), A binder composition for a secondary battery, wherein the ratio of the tensile elastic modulus of the water-soluble polymer (X) to the tensile elastic modulus of the coalesced particles exceeds 10.
    Figure JPOXMLDOC01-appb-C000001
     In general formula (B-1), R 11 to R 13 represent a hydrogen atom, a cyano group or an alkyl group having 1 to 6 carbon atoms, R 14 represents a hydrogen atom, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, cyano group, phenyl group, carboxy group, sulfo group, phosphoric acid group or phosphonic acid group, L 11 is a single bond, an alkylene group having 1 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom, sulfur An atom, a carbonyl group, an imino group, or a combination of these linking groups. * indicates a binding site for incorporation into the main chain of the water-soluble polymer (X).
    In general formula (B-2), R 21 to R 23 represent a hydrogen atom, a cyano group or an alkyl group having 1 to 6 carbon atoms, and R 24 represents a hydrogen atom, an acyl group, a hydroxy group, a phenyl group or a carboxy group. L 21 represents a single bond, an alkylene group having 1 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom, a sulfur atom, a carbonyl group, an imino group, or a linking group combining these. * indicates a binding site for incorporation into the main chain of the water-soluble polymer (X).
  2. 　前記水溶性高分子（Ｘ）が前記一般式（Ｂ－２）で表される構成成分を含む重合体である、請求項１に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 1, wherein the water-soluble polymer (X) is a polymer containing a component represented by the general formula (B-2).
  3. 　前記水溶性高分子（Ｘ）中、前記一般式（Ｂ－２）で表される構成成分の含有量が８０質量％を超える、請求項２に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 2, wherein the content of the component represented by the general formula (B-2) in the water-soluble polymer (X) exceeds 80% by mass.
  4. 　前記一般式（Ｂ－２）で表される構成成分がアクリルアミド成分を含む、請求項２に記載の二次電池用バインダー組成物。 The binder composition for secondary batteries according to claim 2, wherein the component represented by the general formula (B-2) contains an acrylamide component.
  5. 　前記水溶性高分子（Ｘ）が、アクリロニトリル成分、Ｎ－ビニル－２－ピロリドン成分及びスチレン成分の少なくとも１種を、更に含む重合体である、請求項１に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 1, wherein the water-soluble polymer (X) is a polymer further containing at least one of an acrylonitrile component, an N-vinyl-2-pyrrolidone component and a styrene component. .
  6. 　前記水溶性高分子（Ｙ）が多糖類である、請求項１に記載の二次電池用バインダー組成物。 The binder composition for secondary batteries according to claim 1, wherein the water-soluble polymer (Y) is a polysaccharide.
  7. 　前記水溶性高分子（Ｙ）が、カルボキシメチルセルロース、セルロースナノファイバー、ヒドロキシエチルセルロース、ヒドロキシプロピルセルロース及びキサンタンガムの少なくとも１種を含む、請求項６に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 6, wherein the water-soluble polymer (Y) contains at least one of carboxymethyl cellulose, cellulose nanofibers, hydroxyethyl cellulose, hydroxypropyl cellulose and xanthan gum.
  8. 　前記水溶性高分子（Ｘ）の重量平均分子量が１０００００～９０００００である、請求項１に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 1, wherein the water-soluble polymer (X) has a weight average molecular weight of 100,000 to 900,000.
  9. 　前記水溶性高分子（Ｘ）の分子量分布（Ｍｗ／Ｍｎ）が５．０以下である、請求項１に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 1, wherein the water-soluble polymer (X) has a molecular weight distribution (Mw/Mn) of 5.0 or less.
  10. 　前記水溶性高分子（Ｘ）の引張弾性率が４０００ＭＰａ以上である、請求項１に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 1, wherein the water-soluble polymer (X) has a tensile modulus of 4000 MPa or more.
  11. 　前記重合体粒子を構成する重合体が、共役ジエン成分、エチレン性不飽和カルボン酸成分、シアノ基含有エチレン性モノマー成分及び芳香族ビニルモノマー成分の少なくとも１種を含む重合体である、請求項１に記載の二次電池用バインダー組成物。 2. The polymer constituting the polymer particles is a polymer containing at least one of a conjugated diene component, an ethylenically unsaturated carboxylic acid component, a cyano group-containing ethylenic monomer component and an aromatic vinyl monomer component. The binder composition for secondary batteries according to .
  12. 　前記重合体粒子のガラス転移温度が－５０～１５０℃である、請求項１に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 1, wherein the polymer particles have a glass transition temperature of -50 to 150°C.
  13. 　更に水を含む、請求項１に記載の二次電池用バインダー組成物。 The binder composition for secondary batteries according to claim 1, further comprising water.
  14. 　更に周期律表第１族又は第２族に属する金属のイオンの挿入放出が可能な活物質を含む、請求項１に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 1, further comprising an active material capable of inserting and releasing metal ions belonging to Group 1 or Group 2 of the periodic table.
  15. 　前記活物質がケイ素系活物質を含む、請求項１４に記載の二次電池用バインダー組成物。 The binder composition for secondary batteries according to claim 14, wherein the active material contains a silicon-based active material.
  16. 　請求項１４又は１５に記載の二次電池用バインダー組成物を用いて形成した層を有する電極シート。 An electrode sheet having a layer formed using the binder composition for secondary batteries according to claim 14 or 15.
  17. 　正極活物質層及び負極活物質層の少なくとも１つの層が、請求項１４又は１５に記載の二次電池用バインダー組成物を用いて形成された層である、二次電池。 A secondary battery, wherein at least one of the positive electrode active material layer and the negative electrode active material layer is a layer formed using the secondary battery binder composition according to claim 14 or 15.
  18. 　請求項１４又は１５に記載の二次電池用バインダー組成物を用いて電極活物質層を形成することを含む、電極シートの製造方法。 A method for producing an electrode sheet, comprising forming an electrode active material layer using the binder composition for a secondary battery according to claim 14 or 15.
  19. 　請求項１８に記載の製造方法により得られた電極シートを二次電池の電極として組み込むことを含む、二次電池の製造方法。 A method for manufacturing a secondary battery, comprising incorporating the electrode sheet obtained by the manufacturing method according to claim 18 as an electrode of the secondary battery.
PCT/JP2022/046933 2021-12-21 2022-12-20 Binder composition for secondary batteries, electrode sheet, secondary battery, method for producing electrode sheet and method for producing secondary battery WO2023120533A1 (en)

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JP2016126852A (en) * 2014-12-26 2016-07-11 三星エスディアイ株式会社Samsung SDI Co., Ltd. Positive electrode active material layer for secondary battery, wound device, and secondary battery
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