WO2020204058A1 - Liant pour éléments électrochimiques - Google Patents

Liant pour éléments électrochimiques Download PDF

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WO2020204058A1
WO2020204058A1 PCT/JP2020/014986 JP2020014986W WO2020204058A1 WO 2020204058 A1 WO2020204058 A1 WO 2020204058A1 JP 2020014986 W JP2020014986 W JP 2020014986W WO 2020204058 A1 WO2020204058 A1 WO 2020204058A1
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negative electrode
binder
group
crosslinked
polymer
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PCT/JP2020/014986
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English (en)
Japanese (ja)
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悠 石原
津野　利章
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出光興産株式会社
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F20/00—Homopolymers and 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 a salt, anhydride, ester, amide, imide or nitrile thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
    • C08G69/48—Polymers modified by chemical after-treatment
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-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, LIGHT-SENSITIVE OR TEMPERATURE-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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • 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
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • H01M4/134—Electrodes based on metals, Si or alloys
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
    • 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
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • 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 for an electrochemical element, a negative electrode composition for a lithium ion battery, a negative electrode for a lithium ion battery, a lithium ion battery, and a method for producing a binder for an electrochemical element.
  • the secondary battery is a battery that can be repeatedly charged and discharged.
  • secondary batteries a battery that can be repeatedly charged and discharged.
  • electronic devices such as mobile phones and laptop computers, but also in transport aircraft such as automobiles and aircraft.
  • transport aircraft such as automobiles and aircraft.
  • lithium-ion batteries which are lightweight, compact, and have high energy density, are attracting particular attention from various industries and are being actively developed.
  • a lithium ion battery is mainly composed of a positive electrode, an electrolyte, a negative electrode, and a separator.
  • an electrode composition coated on a current collector is usually used.
  • the positive electrode composition used for forming the positive electrode usually contains a positive electrode active material, a conductive auxiliary agent, a binder and a solvent
  • the negative electrode composition used for forming the negative electrode is usually a negative electrode active material. Includes conductive aids, binders and solvents.
  • PVDF polyvinylidene fluoride
  • NMP N-methyl-2-pyrrolidone
  • Patent Document 1 discloses a neutralized product of sodium polyglutamic acid as a water-soluble binder.
  • Patent Document 2 discloses a binder in which polyacrylic acid is crosslinked with a cross-linking agent.
  • Patent Document 3 discloses that a polymer having an acid group is crosslinked and used as a binder for a lithium ion battery.
  • Patent Document 4 discloses that microparticles of crosslinked polyglutamic acid are used as a rheology modifier, there is no mention of binding property as a binder or electrochemical stability.
  • An object of the present invention is to provide a binder for an electrochemical device which is excellent in long-term stability when made into a slurry and can improve the binding property and the cycle characteristics of a battery.
  • binder compositions for electrochemical devices and the like are provided.
  • 1. A crosslink of a polymer having one or more selected from the group consisting of a carboxyl group and a salt thereof and one or more selected from the group consisting of an amide group and an amide bond having two or more functional groups reactive with the carboxyl group.
  • a binder for an electrochemical element which comprises a crosslinked product formed by cross-linking with an agent.
  • the binder for an electrochemical element according to 1 which is used together with an electrode active material and has a shear viscosity of 10 mPa ⁇ s or more and 6000 mPa ⁇ s or less in a 2% by mass aqueous solution of the crosslinked product after thermal decomposition.
  • 3. One or more of the polymers selected from the group consisting of glutamic acid, glutamate, aspartic acid, aspartate, unsaturated carboxylic acid, unsaturated carboxylic acid salt, unsaturated carboxylic acid amide and N-alkyl unsaturated carboxylic acid amide.
  • the binder for an electrochemical element according to 1 or 2 which contains a structure derived from the above as a monomer unit. 4.
  • the polymer has a structure derived from one or more selected from the group consisting of unsaturated carboxylic acids and salts thereof, and one or more selected from the group consisting of unsaturated carboxylic acid amides and N-alkyl unsaturated carboxylic acid amides.
  • the binder for an electrochemical element according to 4 wherein the structure derived from one or more selected from the group consisting of unsaturated carboxylic acids and salts thereof contained in the polymer is less than 30 mol%. 6. 4.
  • the cross-linking agent has an epoxy group or an aziridinyl group.
  • a negative electrode composition for a lithium ion battery which comprises the binder for an electrochemical element according to any one of 9.1 to 8 and a negative electrode active material. 10.
  • 11. 9.
  • a binder for an electrochemical device which is excellent in long-term stability when made into a slurry and can improve the binding property and the cycle characteristics of a battery.
  • the binder for an electrochemical element includes a crosslinked product obtained by cross-linking a polymer with a cross-linking agent.
  • the polymer has one or more selected from the group consisting of a carboxyl group and a salt thereof and one or more selected from the group consisting of an amide group and an amide bond, and the cross-linking agent has reactivity with a carboxyl group. It has two or more functional groups.
  • the "electrochemical element” is an element that utilizes an electrochemical reaction.
  • the electrochemical element comprises an electrode for causing an electrochemical reaction. Examples of such an electrochemical element include a secondary battery such as a lithium ion battery, a capacitor and the like.
  • the crosslinked body used for the binder for an electrochemical element has a high retention of the electrode active material due to having a crosslinked structure, and is also excellent in binding to a current collector. Therefore, even when a silicon-based active material having a large expansion / contraction is used as the active material, good battery cycle characteristics can be obtained. Further, since the crosslinked product has one or more selected from the group consisting of an amide group and an amide bond, the crosslinked product exhibits excellent dispersibility of the active material by interaction with the active material. Therefore, even when the crosslinked product (binder) is contained in the slurry and stored for a long period of time, high long-term stability can be obtained.
  • crosslinked polymer both the polymer (hereinafter, may be referred to as “crosslinked polymer”) and the crosslinking agent forming the crosslinked product can be water-soluble, the crosslinked product can be formed by a crosslinking reaction in an aqueous solution, and is aqueous. It can be applied to electrodes as it is. Therefore, it is not always necessary to use an organic solvent such as NMP, and the environmental load can be reduced.
  • the crosslinked polymer has one or more selected from the group consisting of a carboxyl group and a salt thereof, and one or more selected from the group consisting of an amide group and an amide bond.
  • the total amount of the monomer unit containing a carboxyl group and the monomer unit containing a salt of a carboxyl group is not particularly limited with respect to all the monomer units, and is, for example, 1 mol% or more, 5 mol% or more, or 10 mol% or more. obtain.
  • the crosslinked polymer preferably has a large total amount of the monomer unit containing a carboxyl group and the monomer unit containing a salt of the carboxyl group with respect to all the monomer units, thereby binding to the current collector and the active material.
  • the sex becomes better.
  • the upper limit of the total amount is not particularly limited, but may be, for example, 50 mol%, 70 mol%, 100 mol%.
  • the total amount of the monomer unit containing a carboxyl group, the monomer unit containing a salt of a carboxyl group, the monomer unit containing an amide group, and the monomer unit containing an amide bond with respect to all the monomer units is, for example, 50 mol% or more. , Or 70 mol% or more.
  • the crosslinked product can preferably achieve both binding property and active material dispersibility.
  • the total amount is 1 mol% or more, sufficient binding property is exhibited.
  • the upper limit of such a total amount can be, for example, 100 mol%.
  • the one or more selected from the group consisting of an amide group and an amide bond is specifically one or more selected from the group consisting of a primary amide structure, a secondary amide structure and a tertiary amide structure.
  • the primary amide structure refers to a [-CONH 2 ] structure in a primary amide (R-CONH 2 ), and as a polymer containing a primary amide structure, a polymer containing a primary amide structure in the polymer side chain or polymer terminal. Examples thereof include, but are not limited to, polyacrylamide and polymers thereof.
  • the secondary amide structure refers to the [-CONH-] structure in the secondary amide (R-CONHR'), and the polymer having the secondary amide structure is a polymer containing the secondary amide structure in the polymer side chain or the polymer terminal.
  • examples thereof include polymers containing a secondary amide structure in the main chain of the polymer (monomers are linked by a secondary amide structure), and examples thereof include poly-N-alkylacrylamide and its copolymers, sodium polyglutamate, and the like. However, it is not limited to this.
  • the tertiary amide structure refers to the [-CON (-) 2 ] structure in the tertiary amide (R-CONR'R''), and as a polymer having a tertiary amide structure, the tertiary amide structure is a polymer side chain.
  • a polymer contained at the end of the polymer or a polymer containing a tertiary amide structure in the polymer main chain (the monomer is linked by a tertiary amide structure) can be mentioned, for example, poly N, N-dialkylacrylamide or a copolymer thereof. It can be mentioned, but it is not limited to this.
  • all the monomer units contain a secondary amide structure or a tertiary amide structure, that is, 100 mol% of the monomer units has a primary amide structure and a secondary amide structure. And can be considered as a polymer containing one or more selected from the group consisting of tertiary amide structures.
  • the crosslinked polymer is preferably a polyamide containing, as a monomer unit, a structure derived from one or more selected from the group consisting of glutamic acid, glutamic acid, aspartic acid, and aspartate. Further, the crosslinked polymer preferably contains 50 mol% or more of a structure derived from one or more selected from the group consisting of glutamic acid and a salt thereof as a monomer unit with respect to all the monomer units. Further, the crosslinked polymer is more preferably polyglutamic acid or polyglutamic acid salt.
  • the above amino acid units are easily obtained from nature. Among them, poly- ⁇ -glutamic acid is preferable from the viewpoint of availability because it exists as a high molecular weight homopolyamino acid in nature.
  • the crosslinked polymer preferably contains one or more selected from the group consisting of unsaturated carboxylic acids and salts thereof as a monomer unit.
  • examples of such a monomer unit include acrylic acid, methacrylic acid, acrylate and methacrylic acid.
  • the crosslinked polymer preferably contains 1 or more selected from the group consisting of unsaturated carboxylic acid amides and N-alkyl unsaturated carboxylic acid amides as a monomer unit. Examples of such a monomer unit include acrylamide, N-alkylacrylamide, N-vinylacetamide and the like.
  • the crosslinked polymer is one or more selected from the group consisting of unsaturated carboxylic acids and salts thereof, and one or more selected from the group consisting of unsaturated carboxylic acid amides and N-alkyl unsaturated carboxylic acid amides. Both can be included as monomeric units.
  • the structure derived from the unsaturated carboxylic acid and / or its salt is preferably less than 50 mol%, more preferably less than 30% mol, and particularly preferably less than 20 mol%.
  • 1% mol or more is preferable, and 5% mol or more is more preferable.
  • the structure derived from the unsaturated carboxylic acid amide and / or the N-alkyl unsaturated carboxylic acid amide is preferably 30 mol% or more, more preferably 50 mol% or more, and particularly preferably 70 mol% or more. If it is 30 mol% or more, it can be expected that a crosslinked product having good dispersion stability can be obtained.
  • the upper limit is preferably 99% mol, more preferably 95% mol.
  • the salt of the carboxyl group is preferably a salt of the carboxyl group neutralized with an alkali metal ion, an alkaline earth metal ion or an organic cation.
  • the alkali metal ion include lithium metal ion and sodium metal ion.
  • the alkaline earth metal ion include calcium metal ion and magnesium metal ion.
  • the organic cation for example, an alkylammonium cation having 16 or less carbon atoms, a pyridinium cation having 16 or less carbon atoms, a phosphonium cation having 16 or less carbon atoms, or a sulfonium cation having 16 or less carbon atoms is preferable.
  • an alkylammonium cation having 16 or less carbon atoms or a pyridinium cation having 16 or less carbon atoms is more preferable from the viewpoint of toxicity, cost and the like.
  • Examples of the alkylammonium cation having 16 or less carbon atoms include tetraethylammonium cation and tetrabutylammonium cation, and examples of the pyridinium cation having 16 or less carbon atoms include N-ethylpyridinium cation and N-1.
  • -Butylpyridinium cations and the like are examples, but are not limited thereto.
  • the degree of neutralization of the carboxyl group contained in the crosslinked polymer is not limited, but is, for example, 40 mol% to 100 mol%, preferably 50 mol% to 100 mol%, more preferably 60 mol% to 99 mol%, and 60 mol% to 98 mol%. % Is more preferable.
  • the degree of neutralization indicates the ratio of the number of moles of carboxylate groups to the total number of moles of carboxyl groups and carboxylate groups (salts of carboxyl groups) contained in the polymer as a percentage.
  • the degree of neutralization is a value measured by the method described in Examples.
  • the method for measuring the degree of neutralization when two or more kinds of materials are used in combination as the crosslinked polymer is the same as described above.
  • the degree of neutralization of each material is measured independently, and then the value after mixing is calculated as the average value per mole.
  • the neutralization degree of the polymer A is A (mol%)
  • the amount of the carboxyl group to be added and its salt is a (mol)
  • the neutralization degree of the polymer B is B (mol%)
  • the carboxyl group to be added and its salt is ⁇ (A ⁇ a) + (B ⁇ b) ⁇ / (a + b) (mol%).
  • the degree of neutralization of the carboxyl group contained in the crosslinked polymer is 50 mol% or more, the solubility of the crosslinked polymer in water can be improved.
  • the weight average molecular weight (Mw, PEG (polyethylene glycol) equivalent) of the crosslinked polymer is preferably 100,000 or more and 10,000,000 or less, and 200,000 or more and 9,500,000 or less. Is more preferable, and most preferably 250,000 or more and 8,000,000 or less.
  • the weight average molecular weight is a value measured by the gel permeation chromatography described in Examples.
  • the weight average molecular weight of the crosslinked polymer is 100,000 or more, the crosslinked product is less likely to elute into the electrolytic solution, and the interaction due to the entanglement of the molecular chains can be satisfactorily exhibited.
  • the weight average molecular weight of the crosslinked polymer is 10,000,000 or less, a good viscosity suitable for coating can be imparted to the aqueous solution containing the crosslinked product.
  • the cross-linking agent is used in the above-mentioned cross-linking treatment of the polymer to be cross-linked and has two or more functional groups (for example, two or three) that are reactive with a carboxyl group.
  • the amount of the cross-linking agent added is preferably 0.1 mol% or more and 20.0 mol% or less, more preferably 0.3 mol% or more and 15.0 mol% or less, particularly preferably, with respect to 100 mol% of the polymer to be crosslinked. Is 0.5 mol% or more and 10 mol% or less. If the amount of the cross-linking agent added is 0.1 mol% or more, sufficient cross-linking can be easily obtained, and if it is 20.0 mol% or less, the conductive auxiliary agent and the active material can be sufficiently dispersed.
  • the cross-linking agent is preferably an aqueous cross-linking agent, that is, a water-soluble cross-linking agent.
  • a cross-linking agent include a cross-linking agent having one or more selected from the group consisting of an epoxy group, an aziridinyl group, an oxazoline group, a carbodiimide group or an isocyanate group as a functional group.
  • a cross-linking agent having at least one selected from the group consisting of an epoxy group and an aziridinyl group as a functional group is preferable.
  • cross-linking agent having an epoxy group and the cross-linking agent having an aziridinyl group proceed with the cross-linking reaction in water at an appropriate reaction rate, a uniform solution can be prepared and the cross-linking reaction can proceed rapidly. Further, a cross-linking agent having an aziridinyl group is more preferable from the viewpoint that further improvement in binding property can be expected depending on the polarity of the amino group.
  • the number of the functional groups is usually 1000 or less.
  • cross-linking agent having an aziridine group examples include 2,2-bishydroxymethylbutanol-tris [3- (1-aziridinyl) propinate] (“PZ-33” manufactured by Nippon Catalyst Co., Ltd.), N, N'-hexamethylene-. 1,6-bis (1-aziridinecarboxamide), tetramethylolmethane-tri- ⁇ -aziridinylpropinate, trimethylolpropane tris 2-methyl-1aziridinepropinate, 1,1'-isophthaloylbis (2) -Methyl aziridine), 4,4-bis (ethyleneimincasbonylamino) diphenylmethane and the like, but are not limited thereto.
  • cross-linking agent having an epoxy group examples include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycool diglycidyl ether, polypropylene glycol diglycidyl ether, and neopentyl glycol di.
  • Glycidyl ether 1,4-butanediol glycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylpropan triglycidyl ether, hydrogenated bisphenol A diglycidyl ether, bisphenol A-propylene oxide (PO) 2 mol adduct Diglycidyl ether, glycerol polyglycidyl ether, pentaeristol polyglycidyl ether, sorbitol polyglycidyl ether, 1,7-octadiene epoxide, 1,5-hexadiene epoxide, diglycidyl 1,2-cyclohexanedicarboxylate , Triglycidyl isocyanurate, 4,4-methylenebis (N, N-diglycidyl aniline) and the like, but are not limited thereto.
  • the cross-linking agent 1,4
  • the method of cross-linking the cross-linked polymer with a cross-linking agent is not particularly limited. Although it is possible to mix a cross-linking agent with the powder of the polymer to be cross-linked and cross-link it, it is preferable to carry it in a solvent.
  • the solvent is not particularly limited, and a solvent other than water may be used, or water may be used.
  • the cross-linking method comprises the step of adding the above-mentioned cross-linking agent to an aqueous solution of the cross-linked polymer, preferably uniformly mixing, and cross-linking the cross-linked polymer with the cross-linking agent. As a result, a crosslinked product is preferably obtained.
  • the cross-linking temperature is not particularly limited, and it is preferable to react at 100 ° C. or lower, which is the boiling point of water, from the viewpoint of ease of production and uniformity of reaction.
  • crosslinked product solution a crosslinked polymer obtained by cross-linking the crosslinked polymer with a crosslinking agent in an aqueous solution (crosslinked product solution) can be used as it is as a binder composition as a binder for an electrochemical element.
  • crosslinked product solution is dried by a method such as vacuum drying, heat drying, freeze drying, etc., and the pulverized powder can be used as a binder. The latter method is preferable from the viewpoint of transportation cost and the like because the final form becomes powder.
  • ⁇ Pyrolysis of crosslinked body> it is also preferable to thermally decompose the crosslinked product, adjust the viscosity, and then use it as a binder.
  • the amount of the cross-linking agent added is large (for example, 5 parts by mass or more, 7 parts by mass or more, or 9 parts by mass or more with respect to 100 parts by mass of the non-crosslinked polymer), the gel becomes non-fluid (self-supporting gel).
  • the crosslinked body can be further heated and appropriately thermally decomposed to adjust the viscosity to an appropriate level as a binder.
  • the crosslinked pyrolyzed product thus obtained can be expected to exhibit better binding properties than the non-crosslinked polymer having the same viscosity due to the complex entanglement of the molecules.
  • the pyrolysis of the crosslinked product may be carried out in the state of a gel or an aqueous solution swollen in water, or may be carried out on the powder after drying.
  • the shear viscosity of the 2% by mass aqueous solution of the crosslinked product after thermal decomposition is preferably 6000 mPa ⁇ s or less.
  • the shear viscosity of the 2% by mass aqueous solution of the crosslinked product is more preferably 4000 mPa ⁇ s or less, and further preferably 3000 mPa ⁇ s or less.
  • the lower limit of the shear viscosity is not particularly limited, but for example, it may be 10 mPa ⁇ s, 50 mPa ⁇ s, or 100 mPa ⁇ s.
  • the shear viscosity is 10 mPa ⁇ s or more, the viscosity is suitable for coating, so that the dispersibility of the active material or the like is improved.
  • the shear viscosity of the aqueous solution is a value measured at 25 ° C. and a shear rate of 20 / s using a cone plate viscometer.
  • the shear viscosity of the 2% by mass aqueous solution of the crosslinked product that has not been thermally decomposed is also preferably the above-mentioned value.
  • the crosslinked product uniformly swells or dissolves when it is made into a 0.5% by mass aqueous solution. Uniform swelling or dissolution means that there is no separation of water when mixed with pure water so as to be 0.5% by mass.
  • a binder for a lithium-ion battery an emulsion or the like dispersed in water without being dissolved is also used. However, since a resin having a lighter specific gravity than water generally exists in water as particles, it may occur over time or when dried. , Particles are likely to be unevenly distributed. On the other hand, if the crosslinked product uniformly dissolves or swells at 0.5% by mass, the uneven distribution of the binder as described above can be prevented.
  • the crosslinked product is preferably produced using a crosslinking agent after the polymerization of the crosslinked polymer.
  • a crosslinking agent for example, by proceeding the cross-linking reaction with a homogeneous aqueous solution of the polymer to be cross-linked and the cross-linking agent, a homogeneous cross-linked product can be expected.
  • microgels are less likely to be generated, and defects such as electrodes can be expected to be suppressed when used as a binder.
  • the binder according to one embodiment of the present invention may contain one or both of the unreacted crosslinked polymer and the crosslinking agent that have not been subjected to the crosslinking reaction.
  • the binder according to one embodiment of the present invention may or may not contain a solvent.
  • the binder When containing a solvent, the binder may be a solution in which the crosslinked product is dissolved in the solvent. Water is preferable as the solvent.
  • the binder contains water as a solvent, the higher the content of water in the total solvent, the more preferable, for example, 10% by mass, 30% by mass, 50% by mass, 70% by mass, 80% by mass, 90% by mass, or 100% by mass. Can be%.
  • the solvent of the binder may be water only. By using an aqueous binder that mainly uses water as a solvent, the environmental load can be reduced and the solvent recovery cost can be reduced.
  • solvent other than water examples include alcohol solvents such as ethanol and 2-propanol, acetone, NMP, ethylene glycol and the like.
  • solvents other than water are not limited to these.
  • the binder according to one embodiment of the present invention may contain an emulsion.
  • the emulsion is not particularly limited, but is a non-fluorinated polymer such as a (meth) acrylic polymer, a nitrile polymer, or a diene polymer; a fluoropolymer (fluorine-containing polymer) such as PVDF or PTFE (polytetrafluoroethylene); And so on.
  • the emulsion preferably has excellent bondability and flexibility (flexibility of the film) between particles. From this viewpoint, for example, a (meth) acrylic polymer, a nitrile polymer, a (meth) acrylic-modified fluorine-based polymer, and the like are suitable.
  • the binder according to one embodiment of the present invention may contain a dispersant.
  • the dispersant is not particularly limited, and is, for example, a polymer dispersion such as an anionic, nonionic or cationic surfactant, or a copolymer of styrene and maleic acid (including a half ester copolymer-ammonium salt).
  • Various dispersants such as agents can be used.
  • a dispersant is contained, it is preferably contained in an amount of 5 to 20% by mass with respect to 100% by mass of the conductive auxiliary agent described later.
  • the conductive auxiliary agent can be sufficiently finely divided, and the dispersibility when the active material is mixed can be sufficiently ensured.
  • the binder according to the embodiment of the present invention may contain other water-soluble polymers other than the crosslinked product.
  • water-soluble polymers include polyoxyalkylene, water-soluble cellulose and the like. These can function as thickeners.
  • the binder according to one embodiment of the present invention is 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, 99% by mass or more, 99.5% by mass or more, 99.9% by mass or more, or 100% by mass may consist of the crosslinked product described above and other components optionally contained (one or more selected from the group consisting of solvents, emulsions, dispersants, and other water-soluble polymers).
  • the binder according to the embodiment of the present invention consists only of the above-mentioned crosslinked product, or only the crosslinked product and optional components, the binder may contain unavoidable impurities.
  • the binder or crosslinked body according to the embodiment of the present invention described above can be suitably used in an electrode composition for forming an electrode of an electrochemical element, and a positive electrode composition containing a positive electrode active material and a negative electrode containing a negative electrode active material. It can be used for any of the compositions.
  • the electrochemical element is a secondary battery such as a lithium ion battery
  • the electrode composition is an electrode composition for a secondary battery used for forming an electrode of the secondary battery.
  • the electrode composition for a secondary battery includes the binder for an electrochemical element described above and a positive electrode active material or a negative electrode active material depending on the polarity of the electrode.
  • the content of the crosslinked product is not limited, and can be, for example, 0.5 to 8.0% by mass in the solid content excluding the solvent, and 1.0 to 6.0. It is preferably mass%.
  • the negative electrode composition for a secondary battery including the positive electrode composition for a lithium ion battery and the negative electrode composition for a lithium ion battery described later
  • the negative electrode composition for a secondary battery including the positive electrode composition for a lithium ion battery and the negative electrode composition for a lithium ion battery described later
  • the negative electrode composition for a secondary battery (including the positive electrode composition for a lithium ion battery and the negative electrode composition for a lithium ion battery, which will be described later) has a high holding power of an active material and a conductive auxiliary agent due to cross-linking of a polymer, and is carboxyl.
  • the group and its salt By the action of the group and its salt, it has an interaction with the current collector, so that it can be strongly anchored on the current collector. Therefore, the obtained electrode can improve the durability of the active material even when one or more selected from silicon and tin, which are easily deteriorated due to large expansion and contraction while having a high energy density, are contained as constituent elements. it can.
  • a conductive auxiliary agent may be added to the negative electrode composition for a secondary battery.
  • the output of the lithium ion battery can be increased.
  • the conductive auxiliary agent include conductive carbon and the like.
  • the conductive carbon include carbon black such as Ketjen black and acetylene black; fibrous carbon; graphite and the like. Of these, Ketjen black and acetylene black are preferable.
  • Ketjen Black has a hollow shell structure and easily forms a conductive network. Therefore, the same performance can be exhibited with an addition amount of about half that of the conventional carbon black.
  • Acetylene black is preferable because the impurities produced by using high-purity acetylene gas are very small and the crystallites on the surface are developed.
  • the carbon black which is a conductive auxiliary agent, preferably has an average particle size of 1 ⁇ m or less.
  • a conductive auxiliary agent having an average particle diameter of 1 ⁇ m or less it is possible to obtain an electrode having excellent electrical characteristics such as output characteristics when the electrode composition of this embodiment is used as an electrode.
  • the average particle size of the conductive auxiliary agent is more preferably 0.01 to 0.8 ⁇ m, still more preferably 0.03 to 0.5 ⁇ m.
  • the average particle size of the conductive auxiliary agent is a value measured by a particle size distribution meter for dynamic light scattering (for example, the refractive index of the conductive auxiliary agent is 2.0).
  • the fibrous carbon preferably has a thickness of 0.8 nm or more and 500 nm or less and a length of 1 ⁇ m or more and 100 ⁇ m or less. If the thickness is within the range, sufficient strength and dispersibility can be obtained, and if the length is within the range, it is possible to secure a conductive path due to the fiber shape.
  • the positive electrode composition for a lithium ion battery and the negative electrode composition for a lithium ion battery will be described below, and these may be one embodiment of the above-mentioned electrode composition, and appropriately include the configuration described for the electrode composition. be able to.
  • the positive electrode composition for a lithium ion battery according to an embodiment of the present invention includes the binder for an electrochemical element described above and the positive electrode active material.
  • the positive electrode active material contained in the positive electrode composition is preferably an active material capable of occluding and releasing lithium ions.
  • a positive electrode active material By using such a positive electrode active material, a positive electrode of a lithium ion battery can be suitably formed.
  • the positive electrode active material include various oxides and sulfides, and specific examples thereof include manganese dioxide (MnO 2 ), lithium manganese composite oxide (for example, LiMn 2 O 4 or LiMn O 2 ), and lithium nickel composite oxide.
  • LiNiO 2 lithium cobalt composite oxide (LiCoO 2 ), lithium nickel cobalt composite oxide (for example, LiNi 1-x Co x O 2 ), lithium-nickel-cobalt-aluminum composite oxide (LiNi 0.8 Co) 0.15 Al 0.05 O 2 ), Lithium manganese cobalt manganese composite oxide (eg LiMn x Co 1-x O 2 ), Lithium nickel cobalt manganese composite oxide (eg LiNi x Mn y Co 1-x-y O 2) ), Polyanionic lithium compounds (for example, LiFePO 4 , LiCoPO 4 F, Li 2 MnSiO 4, etc.), vanadium oxides (for example, V 2 O 5 ) and the like.
  • LiNiO 2 lithium cobalt composite oxide
  • LiNi 1-x Co x O 2 lithium-nickel-cobalt-aluminum composite oxide (LiNi 0.8 Co) 0.15 Al 0.05 O 2 )
  • lithium manganese composite oxide LiMn 2 O 4
  • lithium nickel composite oxide LiNiO 2
  • lithium cobalt composite oxide LiCoO 2
  • lithium nickel cobalt composite oxide LiNi 0.8 Co 0.
  • lithium-nickel-cobalt-aluminum composite oxide LiNi 0.8 Co 0.15 Al 0.05 O 2
  • lithium manganese cobalt composite oxide LiN x Co 1-x O 2
  • lithium Nickel-cobalt-manganese composite oxide for example, LiNi x Mn y Co 1-x-y O 2
  • Li excess nickel-cobalt-manganese composite oxide LiNi 0 .5 Mn 1.5 O 4 is preferred.
  • the positive electrode active material from the viewpoint of the battery voltage, LiMO 2, LiM 2 O 4 , Li 2 MO 3 or LiMXO 3or4, Li composite oxide represented by Li 2 MXO 4 is preferred.
  • M is composed of one or more transition metal elements selected from Ni, Co, Mn and Fe, but in addition to the transition metal, Al, Ga, Ge, Sn, Pb, Sb, Bi and Si , P, B and the like may be added.
  • 80% or more of X is composed of one or more elements selected from P, Si and B.
  • a composite oxide of LiMO 2 is more preferred.
  • the Li composite oxide has a large electric capacity (Ah / L) per volume as compared with a positive electrode material such as a conductive polymer, and is effective in improving the energy density.
  • the positive electrode active material is preferably a Li composite oxide represented by LiMO 2 from the viewpoint of battery capacity.
  • M preferably contains Ni, more preferably 25% or more of M is Ni, and even more preferably 45% or more of M. When M contains Ni, the electric capacity (Ah / kg) per weight of the positive electrode active material becomes larger than in the case where M is Co and Mn, which is effective in improving the energy density.
  • the positive electrode active material can also be coated with a metal oxide, carbon or the like.
  • a metal oxide or carbon By coating the positive electrode active material with a metal oxide or carbon, deterioration of the positive electrode active material when it comes into contact with water can be suppressed, and oxidative decomposition of the binder or electrolytic solution during charging can be suppressed.
  • the metal oxide used for coating is not particularly limited, but is a metal oxide such as Al 2 O 3 , ZrO 2 , TiO 2 , SiO 2 , Al PO 4, or a compound represented by Li ⁇ M ⁇ O ⁇ containing Li. It may be.
  • M is one or more metals selected from Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ag, Ta, W, and Ir. It is an element, and 0 ⁇ ⁇ ⁇ 6, 1 ⁇ ⁇ ⁇ 5, and 0 ⁇ ⁇ 12.
  • the content ratio is preferably 0.5 to 7/80 to 97/1 to 10/0 to 6/0 to 2, and more preferably 1.0 to 6/85 to 97 / 1.5 to 8.
  • the other components referred to here refer to components other than the crosslinked body, the positive electrode active material, the conductive auxiliary agent and the emulsion, and include a dispersant, a water-soluble polymer other than the crosslinked body and the like.
  • the positive electrode composition containing the crosslinked body described above secures dispersion stability of filler components such as a positive electrode active material and a conductive auxiliary agent, and further has excellent coating film forming ability and adhesion to a base material. ..
  • a positive electrode formed from such a positive electrode composition can exhibit excellent performance as a positive electrode of a lithium ion battery.
  • the positive electrode composition is a positive electrode water-based composition containing the above-mentioned crosslinked body, positive electrode active material, conductive additive, and water.
  • the method for producing the positive electrode aqueous composition is not particularly limited, and a method in which the positive electrode active material and the conductive auxiliary agent are uniformly dispersed is preferable, and for example, a bead mill, a ball mill, a stirring type mixer or the like is used. Can be done.
  • the negative electrode composition for a lithium ion battery according to an embodiment of the present invention includes the binder for an electrochemical element described above and the negative electrode active material.
  • Negative electrode active materials are carbon materials such as graphite, natural graphite, artificial graphite, hard carbon and soft carbon; polyacene-based conductive polymers; composite metal oxides such as lithium titanate; silicon, silicon alloys, silicon oxides and silicon. Materials usually used in lithium ion secondary batteries, such as composite oxides and compounds that form an alloy with lithium such as tin, can be used.
  • the negative electrode active material preferably contains one or more selected from the group consisting of graphite, Si (silicon, silicon alloy, silicon composite oxide, etc.) and Sn (tin).
  • lithium or other metal may be contained in advance before blending with the negative electrode composition. It is also preferable to coat the active material with a conductive substance such as carbon.
  • the content of the active material containing Si element or Sn element contained in the negative electrode active material is not particularly limited, and although the capacity increases as the content increases, the degree of expansion and contraction increases and the cycle characteristics are maintained. It becomes difficult to do. Therefore, the content of the active material containing the Si element or the Sn element is preferably 1% by mass or more, more preferably 5% by mass or more, based on the solid content of the entire electrode mixture, that is, the negative electrode composition. Particularly preferably, it is 8% by mass or more.
  • the content of the active material containing Si element or Sn element is preferably 90% by mass or less, more preferably 50% by mass or less, and particularly preferably 30 with respect to the entire electrode mixture, that is, the solid content of the negative electrode composition. It is mass% or less.
  • the solid content of the negative electrode composition examples include a modified polymer, a negative electrode active material, a conductive auxiliary agent, an emulsion, and other components other than these components.
  • the other components referred to here mean components other than the modified polymer, the negative electrode active material, the conductive auxiliary agent and the emulsion, and include a dispersant, a water-soluble polymer other than the modified polymer and the like.
  • the content ratio (mass ratio) of the crosslinked product, the negative electrode active material, the conductive auxiliary agent, the emulsion, and other components other than these components in the solid content of the negative electrode composition is the crosslinked body / negative electrode active material /
  • the conductive additive / emulsion / other component 0.3 to 8/80 to 99/0 to 10/0 to 9/0 to 5 is preferable. With such a content ratio, the output characteristics and electrical characteristics of the lithium ion battery including the negative electrode formed from the negative electrode composition can be improved.
  • the content ratio is preferably 0.5 to 7/85 to 98/0 to 5/0 to 3/0 to 3, and more preferably 1.0 to 6/85 to 97/0 to 4/0 to.
  • the other components referred to here mean components other than the crosslinked body, the negative electrode active material, the conductive auxiliary agent and the emulsion, and include a dispersant, a water-soluble polymer other than the crosslinked body and the like.
  • the negative electrode composition containing the crosslinked product described above has good long-term stability, excellent coating film forming ability, and excellent adhesion to the base material. Such a negative electrode composition can obtain good productivity without causing a decrease in yield due to sedimentation, separation, etc. in the manufacturing process, and the formed negative electrode exhibits excellent performance as a negative electrode of a lithium ion battery. it can.
  • the negative electrode composition is a negative electrode aqueous composition containing the above-mentioned crosslinked body, negative electrode active material, conductive auxiliary agent and water.
  • the method for producing the negative electrode aqueous composition is not particularly limited.
  • a method in which the negative electrode active material and the conductive auxiliary agent are uniformly dispersed is preferable, and for example, it can be produced by using a bead mill, a ball mill, a stirring type mixer or the like.
  • the negative electrode composition preferably contains water and is a slurry.
  • the negative electrode composition which contains water and is a slurry, exhibits dispersion stability of active materials, conductive auxiliaries, and the like for a long period of time. Therefore, even if the negative electrode composition is prepared in a battery factory or the like and then left to stand, precipitation or separation does not occur, and a good negative electrode can be formed. As a result, the effects of improving the yield of the negative electrode and improving the productivity can be obtained. Such an effect can also be obtained in the case of a positive electrode composition containing water and being a slurry.
  • the electrode composition described above may consist of a crosslinked body, an active material, a conductive auxiliary agent, and may further contain a solvent. ..
  • a solvent for example, 70% by mass or more, 80% by mass or more, or 90% by mass or more of the electrode composition may be a crosslinked product, an active material, a conductive additive, and a solvent.
  • the electrode composition may consist only of a crosslinked product, an active material, a conductive additive and a solvent. In this case, unavoidable impurities may be contained.
  • the solvent contained in the electrode composition the solvent exemplified for the binder composition can be used, and a solvent other than the solvent exemplified for the binder composition may be used.
  • the electrode composition is mainly used for a lithium ion battery has been described above, but the present invention is not limited to this.
  • the electrode composition can be used to produce electrodes for various electrochemical devices other than lithium ion batteries.
  • the method for producing an electrode according to an embodiment of the present invention includes a step of forming an electrode by applying the electrode composition described above onto a current collector and drying the electrode composition.
  • the electrode composition is a positive electrode composition containing a positive electrode active material
  • the positive electrode composition can be made into a positive electrode by applying and drying the positive electrode composition on a positive electrode current collector.
  • the electrode composition is a negative electrode composition containing a negative electrode active material
  • the negative electrode composition can be obtained as a negative electrode by applying and drying the negative electrode composition on the negative electrode current collector.
  • the positive electrode current collector is not particularly limited as long as it has electron conductivity and can energize the retained positive electrode material.
  • the positive electrode current collector contains, for example, conductive substances such as C, Ti, Cr, Mo, Ru, Rh, Ta, W, Os, Ir, Pt, Au, and Al; and two or more of these conductive substances. Alloys (eg, stainless steel) can be used. C, Al, stainless steel, nickel-plated steel sheet, etc. are preferable as the positive electrode current collector from the viewpoint of high electrical conductivity, stability in the electrolytic solution, and oxidation resistance, and Al is preferable from the viewpoint of material cost. ..
  • stainless steel having corrosion resistance to alkali can also be used.
  • the negative electrode current collector can be used without any particular limitation as long as it is a conductive material, but it is preferable to use a material that is electrochemically stable during the battery reaction, and for example, copper, stainless steel, nickel-plated steel plate or the like is used. can do. Copper having high conductivity is preferable as the carbon-based active material, and stainless steel having excellent strength is preferably applied to the active material containing silicon, tin, etc., which have large expansion and contraction.
  • the shape of the current collector is not particularly limited, but a foil-like base material, a three-dimensional base material, or the like can be used. Of these, when a three-dimensional base material (foam metal, mesh, woven fabric, non-woven fabric, expand, etc.) is used, even an electrode composition containing a binder composition that lacks adhesion to a current collector is expensive. An electrode having a capacitance density can be obtained, and high rate charge / discharge characteristics are also improved.
  • the capacity can be increased by forming a primer layer on the surface of the current collector in advance.
  • the primer layer may be one that has good adhesion between the active material layer and the current collector and has conductivity.
  • a primer layer can be formed by applying a crosslinked body mixed with a carbon-based conductive auxiliary agent on a current collector with a thickness of 0.1 ⁇ m to 50 ⁇ m.
  • the conductive auxiliary agent for the primer layer is preferably carbon powder.
  • a metal-based conductive auxiliary agent can increase the capacitance density, but the input / output characteristics may deteriorate, while a carbon-based conductive auxiliary agent can improve the input / output characteristics.
  • Examples of the carbon-based conductive auxiliary agent include Ketjen black, acetylene black, vapor phase carbon fiber, graphite, graphene, carbon tube, etc., and these types may be used alone or in combination of two or more. Good. Of these, Ketjen black or acetylene black is preferable from the viewpoint of conductivity and cost.
  • the crosslinked body for the primer layer is not particularly limited as long as it can bind a carbon-based conductive auxiliary agent.
  • the primer layer is formed using an aqueous binder such as PVA, CMC, or sodium alginate in addition to the binder of the present invention, the primer layer may be dissolved when the active material layer is formed, and the effect may not be remarkably exhibited. is there. Therefore, when using such an aqueous binder, it is advisable to crosslink the primer layer in advance.
  • cross-linking material examples include a zirconia compound, a boron compound, a titanium compound, and the like, and it is preferable to add 0.1 to 20 wt% with respect to the amount of the binder when forming the slurry for the primer layer.
  • the primer layer is a foil-shaped current collector, and not only can the capacitance density be increased by using an aqueous binder, but also the polarization becomes small and the high rate charge / discharge characteristics are good even when charging / discharging is performed with a high current. Can be.
  • the primer layer is effective not only on the foil-shaped current collector, but also on the three-dimensional base material.
  • FIG. 1 is a schematic cross-sectional view showing an embodiment of a lithium ion secondary battery in which a binder for an electrochemical element is used for a positive electrode and / or a negative electrode.
  • a positive electrode current collector 7, a positive electrode 6, a separator and an electrolytic solution 5, a lithium metal 4 (negative electrode), and a SUS spacer 3 are laminated in this order on a positive electrode can 9.
  • the laminated body is fixed on both sides in the stacking direction by gaskets 8 and in the stacking direction by a negative electrode can 1 via a wave washer 2.
  • a non-aqueous electrolytic solution which is a solution in which an electrolyte is dissolved in an organic solvent
  • the organic solvent include carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate; lactones such as ⁇ -butyrolactone; trimethoxymethane, 1,2-dimethoxyethane and diethyl ether.
  • Nitrogens Methyl formate, Methyl acetate, Butyl acetate, Methyl propionate, Ethyl propionate, Esters such as phosphate triesters; Grimes such as diglyme, triglime, tetraglyme; Acetone, diethyl ketone, methyl ethyl ketone, methyl Ketones such as isobutyl ketone; sulfones such as sulfolane; oxazolidinones such as 3-methyl-2-oxazolidinone; sulton species such as 1,3-propane sulton, 4-butane sulton, nafta sulton and the like can be mentioned. These organic solvents may be used alone or in combination of two or more.
  • the electrolyte for example LiClO 4, LiBF 4, LiI, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, LiCl, LiBr, LiB (C 2 H 5) 4, LiCH 3
  • the non-aqueous electrolytic solution a solution in which LiPF 6 is dissolved in carbonates is preferable, and the solution is particularly suitable as an electrolytic solution for a lithium ion secondary battery.
  • a separator for preventing a short circuit of current due to contact between the positive electrode and the negative electrode it is preferable to use a material that can surely prevent the contact between the two electrodes and allows the electrolytic solution to pass through or be contained.
  • a non-woven fabric made of a synthetic resin such as polytetrafluoroethylene, polypropylene, or polyethylene, a glass filter, a porous ceramic film, a porous thin film, or the like can be used.
  • the separator In order to impart functions such as heat resistance to the separator, it may be coated with a composition (coating liquid) containing the binder composition of the present invention.
  • a composition (coating liquid) containing the binder composition of the present invention In addition to the binder composition of the present invention, ceramic particles such as silica, titanium oxide, aluminum oxide, zirconium oxide, magnesium oxide, niobium oxide, and barium oxide are mixed and coated on the separator to improve the heat resistance of the separator. it can.
  • the separator base material in the above coating can be used without limitation, but a porous thin film is preferable, and a polyolefin porous film produced by a wet method or a dry method can be preferably used.
  • the above composition can be coated on the positive electrode or the negative electrode and used as a protective film.
  • a protective film By forming such a protective film on the positive electrode or the negative electrode, improvement of the cycle characteristics of the battery can be expected.
  • a secondary battery can be manufactured, for example, by putting a negative electrode, a separator impregnated with an electrolyte, and a positive electrode into an exterior body and sealing the battery.
  • a known method such as crimping or laminating seal may be used.
  • the electrochemical element is a lithium ion secondary battery and the above-mentioned crosslinked body is used as the binder for the negative electrode and the binder for the positive electrode has been mainly described, but the present invention is not limited thereto. ..
  • the crosslinked body can also be suitably used as another electrochemical element, for example, a binder for separator coating of a lithium ion battery, a binder for an electric double layer capacitor, and the like.
  • the crosslinked body can also be suitably used for other electrochemical elements exposed to a redox environment, such as a binder for a separator coating of a lithium ion battery and a binder for a capacitor.
  • Electrochemical elements such as lithium ion batteries and electric double layer capacitors manufactured by using the above-mentioned crosslinked body can be used in various electric devices and vehicles.
  • Examples of electric devices include mobile phones and laptop computers, and examples of vehicles include automobiles, railways, airplanes, etc., but the present invention is not limited to the above.
  • Example 1-1 Preparation of electrode composition
  • Poly- ⁇ -glutamic acid manufactured by Bioleaders Co., Ltd., 2000 kDa, acid type
  • an aqueous solution of lithium hydroxide monohydrate manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.
  • Poly- ⁇ -Glutamic acid lithium (a crosslinked polymer containing a salt of a carboxyl group and an amide bond) was obtained.
  • the obtained lithium poly- ⁇ -glutamate was subjected to weight average molecular weight measurement and elemental analysis under the following equipment and conditions to evaluate the degree of neutralization.
  • the degree of neutralization was calculated by measuring the ratio of N and Na by elemental analysis after confirming that the monomer unit was a homopolymer containing only glutamic acid or only glutamic acid by nuclear magnetic resonance spectroscopy (NMR). .. As a result, the weight average molecular weight of lithium poly- ⁇ -glutamate was 529,000, and the degree of neutralization was 96%.
  • the negative electrode active material (S1000 manufactured by GELON) was added and mixed so that the solid content mass ratio of graphite: silicon: binder was 87.3: 9.7: 3 (mass ratio), and the solid content was prepared as a negative electrode composition. A slurry having a concentration of 40% by mass was obtained.
  • Example 1-2 (Preparation of electrode) The negative electrode composition obtained in Example 1-1 using a film applicator with a micrometer "SA-204" (manufactured by Tester Sangyo Co., Ltd.) and an automatic coating device "PI-1210" (manufactured by Tester Sangyo Co., Ltd.). Is coated on a Cu foil having a thickness of 10 ⁇ m, dried at 60 ° C. for 10 minutes, vacuum dried at 120 ° C. for 5 hours, pressed at room temperature, 3.5 to 4 mAh / cm 2 , and a void ratio of 20 to 30. % Electrode sheet was prepared. The obtained electrode sheet was punched to a diameter of 14 mm and vacuum dried at 120 ° C. for 5 hours to obtain an electrode. There was no powder falling during electrode punching.
  • Example 1-3 Preparation of secondary battery
  • a gasket was fitted to the positive electrode can, which is a component of the coin cell, in an argon-substituted glove box controlled to have an oxygen concentration of 10 ppm or less and a water concentration of 5 ppm or less, and the electrode obtained in Example 1-2 was used as the positive electrode portion.
  • the separator was laminated on this, and the electrolytic solution was added.
  • the negative electrode, the SUS spacer, the wave washer, and the negative electrode can were stacked in this order and sealed with a caulking machine (“automatic coin cell caulking machine” manufactured by Hosen Co., Ltd.) to manufacture a coin cell (lithium ion secondary battery).
  • the obtained coin cell has the structure shown in FIG. However, since this coin cell is a negative electrode half cell for evaluating the negative electrode material, the electrode (negative electrode) manufactured above was used in the portion where the positive electrode member is originally arranged.
  • Each component of the coin cell is as follows. ⁇ Coin cell components> Positive electrode can, gasket, SUS spacer, wave washer and negative electrode can: "Lithium ion secondary battery coin cell member (for CR2032)" manufactured by Hosen Co., Ltd.
  • Electrode separator obtained in Example 1-2 Glass filter (GF / A manufactured by Whatman)
  • Negative electrode (counter electrode and reference electrode): Li metal electrolyte punched to a diameter of 15 mm: Solution of electrolyte LiPF 6 (1 mol / L, solvent is a mixed solvent of EC (ethylene carbonate) and DEC (diethyl carbonate), EC: DEC (volume) Ratio) 3: 7, manufactured by Kishida Chemical Co., Ltd.) with 10% by mass of FEC (fluoroethylene carbonate, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., for battery research) and mixed uniformly.
  • the discharge capacity which is the charge / discharge characteristic of the obtained coin cell, was evaluated under the following measurement conditions. As a result, the capacity retention rate was 95%. The capacity retention rate was calculated by using (64th discharge capacity) / (first discharge capacity) as the capacity retention rate under the following measurement conditions.
  • Example 2 As a polymer, a poly (acrylamide-sodium acrylate) copolymer (manufactured by Sigma-Aldrich, containing a poly (acrylamide-co-acrylic acid) sodium salt, Mw520,000, Mn150,000 (Typical), acrylicamide-80% by mass, A 20% by mass aqueous solution was prepared using a crosslinked polymer containing a salt of a carboxyl group and an amide bond), and an aziridine derivative "PZ-33" (manufactured by Nippon Catalyst Co., Ltd.) was added to 100 parts by mass of the crosslinked polymer as a crosslinking agent. 3 parts by mass (0.5 mol%) was added thereto, and the mixture was heated at 35 ° C.
  • a poly (acrylamide-sodium acrylate) copolymer manufactured by Sigma-Aldrich, containing a poly (acrylamide-co-acrylic acid) sodium salt, Mw520,000, Mn150,000 (Typical), acrylicamide-
  • aqueous solution of the crosslinked product When the obtained crosslinked aqueous solution was diluted with a 0.5% by mass aqueous solution, a swollen gel was obtained.
  • the weight average molecular weight of the polymer before cross-linking was 430,000, the degree of neutralization was 50%, the composition ratio of the monomers was 86 mol% of acrylamide, and 14 mol% of acrylic acid and sodium acrylate.
  • the method for measuring the weight average molecular weight is the same as in Example 1-1.
  • the degree of neutralization was measured by the same method as in Example 1-1 after confirming that the monomer unit was a homopolymer containing only acrylamide, sodium acrylate and salts thereof.
  • Negative electrode compositions, electrodes and batteries were prepared and evaluated in the same manner as in Examples 1-1 to 1-3 except that the crosslinked aqueous solution obtained above before dilution was used as the binder.
  • the obtained negative electrode composition separation and sedimentation of the negative electrode composition were not observed in the long-term storage test, and the obtained negative electrode composition showed excellent long-term stability.
  • the peel strength of the electrode was 154 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 91%.
  • Example 3 Poly- ⁇ -monosodium glutamate (manufactured by Vedan Enterprise Corporation, ⁇ -Polyglutamic Acid (Na + form, HM), crosslinked polymer containing a salt of a carboxyl group and an amide bond) was subjected to molecular weight measurement and elemental analysis in the same manner as in Example 1-1. The analysis was performed and the degree of neutralization was evaluated. As a result, the weight average molecular weight of poly- ⁇ -monosodium glutamate was 190,000, and the degree of neutralization was 98%.
  • silicon silicon-containing negative electrode in which silicon is dispersed in a carbon matrix
  • the active material S1000 manufactured by GELON
  • a slurry having a solid content concentration of 40% by mass was obtained.
  • the obtained negative electrode composition was subjected to a long-term storage test in the same manner as in Example 1-1. Further, electrodes and batteries were prepared and evaluated in the same manner as in Examples 1-2 to 1-3 except that the obtained negative electrode composition was used. In the obtained negative electrode composition, separation and sedimentation of the negative electrode composition were not observed in the long-term storage test, and the obtained negative electrode composition showed excellent long-term stability. The peel strength of the electrode was 94.5 N / m, showing good binding properties. The capacity retention rate of the battery was 86%.
  • Example 4 In Example 3, EGDG (ethylene glycol diglycidyl ether, manufactured by Tokyo Kasei Kogyo Co., Ltd., the chemical structural formula is as follows), which is an epoxy derivative, was used as a cross-linking agent by 2.3 parts by mass with respect to 100 parts by mass of the cross-linked polymer. (2.0 mol%) was added, and an aqueous crosslinked product was obtained in the same manner as in Example 3 except that the mixture was heated at 70 ° C. for 4 hours. When the crosslinked powder was prepared in the same manner as in Example 3 and the obtained crosslinked powder was made into a 0.5% by mass aqueous solution, a uniformly swollen gel was obtained.
  • EGDG ethylene glycol diglycidyl ether, manufactured by Tokyo Kasei Kogyo Co., Ltd., the chemical structural formula is as follows
  • EGDG ethylene glycol diglycidyl ether, manufactured by Tokyo Kasei Kogyo Co., Ltd., the chemical structural formula is as follows
  • a negative electrode composition, an electrode, and a battery were prepared and evaluated in the same manner as in Example 3 except that the crosslinked powder obtained above was used as the binder.
  • the obtained negative electrode composition separation and sedimentation of the negative electrode composition were not observed in the long-term storage test, and the obtained negative electrode composition showed excellent long-term stability.
  • the peel strength of the electrode was 141 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 94%.
  • Example 5 In Example 3, PEGDG (poly (ethylene glycol) diglycidyl ether, manufactured by Sigma-Aldrich Japan, Mn500), which is an epoxy derivative, was added as a cross-linking agent to 6.7 parts by mass (2.0 mol) with respect to 100 parts by mass of the crosslinked polymer. %) In addition, a crosslinked aqueous solution was obtained in the same manner as in Example 3 except that the mixture was heated at 70 ° C. for 4 hours. A crosslinked powder was prepared in the same manner as in Example 3, and the obtained crosslinked powder was made into a 0.5% by mass aqueous solution to obtain a uniformly swollen gel.
  • PEGDG poly (ethylene glycol) diglycidyl ether, manufactured by Sigma-Aldrich Japan, Mn500
  • a negative electrode composition, an electrode, and a battery were prepared and evaluated in the same manner as in Example 3 except that the crosslinked powder obtained above was used as the binder.
  • the obtained negative electrode composition separation and sedimentation of the negative electrode composition were not observed in the long-term storage test, and the obtained negative electrode composition showed excellent long-term stability.
  • the peel strength of the electrode was 98.2 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 91%.
  • Example 6 In Example 3, TMPTGE (trimethylolpropane triglycidyl ether, manufactured by Sigma-Aldrich Japan, the chemical structural formula is as follows), which is an epoxy derivative, was used as a cross-linking agent in an amount of 2.7 parts by mass with respect to 100 parts by mass of the polymer to be cross-linked. An aqueous crosslinked product was obtained in the same manner as in Example 3 except that (1.3 mol%) was added and the mixture was heated at 70 ° C. for 4 hours. When the crosslinked powder was prepared in the same manner as in Example 3 and the obtained crosslinked powder was made into a 0.5% by mass aqueous solution, a uniformly swollen gel was obtained.
  • TMPTGE trimethylolpropane triglycidyl ether, manufactured by Sigma-Aldrich Japan, the chemical structural formula is as follows
  • An aqueous crosslinked product was obtained in the same manner as in Example 3 except that (1.3 mol%) was added and the mixture was heated at 70
  • a negative electrode composition, an electrode, and a battery were prepared and evaluated in the same manner as in Example 3 except that the crosslinked powder obtained above was used as the binder.
  • the obtained negative electrode composition separation and sedimentation of the negative electrode composition were not observed in the long-term storage test, and the obtained negative electrode composition showed excellent long-term stability.
  • the peeling strength of the electrode was 119 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 89%.
  • Comparative Example 1 As a water-soluble polymer, polyacrylic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., average molecular weight 250,000) is used, and lithium hydroxide monohydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) is used in the calculation. The sum was 50%, water was added and kneaded to prepare a 5% by mass aqueous solution (the obtained polymer was a polymer having a carboxyl group and a salt thereof).
  • the active material (S1000 manufactured by GELON) was added and mixed so that the solid content mass ratio of graphite: silicon: binder was 87.3: 9.7: 3 (mass ratio), and the solid content concentration was obtained as a negative electrode composition. A 40% by mass slurry was obtained.
  • the obtained negative electrode composition was subjected to a long-term storage test in the same manner as in Example 1-1. Further, electrodes and batteries were prepared and evaluated in the same manner as in Examples 1-2 to 1-3 except that the obtained negative electrode composition was used. The obtained negative electrode composition was clearly separated in the long-term storage test, and a precipitate was observed at the bottom. The peel strength of the electrode was 136 N / m, showing good binding properties. The capacity retention rate of the battery was 93%.
  • Comparative Example 1 the electrode and the battery are manufactured immediately after the negative electrode composition is manufactured, but since the negative electrode composition is not stable, it may be difficult to handle or extra cost may be required from the viewpoint of manufacturing. In addition, the negative electrode composition that has settled may be used unnoticed, leading to a decrease in yield.
  • Example 7 Using the same cross-linked polymer as in Example 4, the concentration of the cross-linked polymer aqueous solution was 10% by mass, and the epoxy derivative EGDG (ethylene glycol diglycidyl ether, manufactured by Tokyo Kasei Kogyo Co., Ltd.) was used as the cross-linking agent for the cross-linked polymer 100.
  • the heating step of adding 10 parts by mass (8.7 mol%) to parts by mass and heating at 90 ° C. for 5.3 hours to obtain an aqueous crosslinked product the crosslinked product became fluid when 3 hours had passed from the start of heating. Although it was a gel without epoxy, it became a fluid aqueous solution by continuing heating.
  • EGDG ethylene glycol diglycidyl ether
  • a crosslinked powder was obtained from the crosslinked aqueous solution in the same manner as in Example 3.
  • the shear viscosity of the aqueous solution was 1580 mPa ⁇ s at a shear rate of 20 / s.
  • the shear viscosity was measured at 25 ° C. using a cone plate viscometer (“DV2TCP” manufactured by Brookfield) as a measuring instrument and “CP52Z” as a cone plate.
  • the shear viscosity of the 2% by mass aqueous solution of the crosslinked product obtained in Comparative Example 1 was as high as 7515 mPa ⁇ s, which may cause a problem in handling. However, if the shear viscosity of Example 7 is used, The fluidity of the polymer solution was good and it was easy to handle.
  • the mixture was mixed so that the solid content mass ratio of graphite: SiO: binder was 87.3: 9.7: 3 (mass ratio), and water was added to prepare a slurry having a solid content concentration of 60% by mass as a negative electrode composition. Obtained.
  • the obtained negative electrode composition was subjected to a long-term storage test in the same manner as in Example 1-1. Further, electrodes and batteries were prepared and evaluated in the same manner as in Examples 1-2 to 1-3 except that the obtained negative electrode composition was used.
  • the obtained negative electrode composition showed good long-term stability without any clear separation in the long-term storage test.
  • the peeling strength of the electrode was 194 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 82%.
  • Example 8 In Example 5, 10 parts by mass (3 mol%) of a cross-linking agent (epoxy derivative, PEGDG) was added to 100 parts by mass of the polymer to be cross-linked, and the mixture was heated at 90 ° C. for 15 hours in the same manner as in Example 5. A body aqueous solution was obtained. In the heating step, the crosslinked product became a non-fluid gel 7 hours after the start of heating, but by continuing heating, it became a fluid aqueous solution. A crosslinked powder was obtained from the crosslinked aqueous solution in the same manner as in Example 3. When the obtained crosslinked powder was made into a 2% by mass aqueous solution, a uniform aqueous solution was obtained.
  • a cross-linking agent epoxy derivative, PEGDG
  • the shear viscosity of the aqueous solution was 801 mPa ⁇ s at a shear rate of 20 / s.
  • the method for measuring the shear viscosity is the same as in Example 7, and the same applies to the following examples.
  • a negative electrode composition (slurry) was prepared in the same manner as in Example 7 except that the obtained crosslinked powder was used as a binder.
  • the solid content concentration was 60% by mass.
  • the obtained negative electrode composition was subjected to a long-term storage test in the same manner as in Example 1-1. Further, electrodes and batteries were prepared and evaluated in the same manner as in Examples 1-2 to 1-3 except that the obtained negative electrode composition was used.
  • the obtained negative electrode composition showed good long-term stability without any clear separation in the long-term storage test.
  • the peel strength of the electrode was 177 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 79%.
  • Example 9 In Example 3, 11 parts by mass (3.9 mol%) of a cross-linking agent (aziridine derivative “PZ-33”) was added to 100 parts by mass of the polymer to be cross-linked, and the mixture was heated at 90 ° C. for 9 hours. A crosslinked aqueous solution was obtained in the same manner as above. In the heating step, the crosslinked product became a non-fluid gel 2 hours after the start of heating, but by continuing heating, it became a fluid aqueous solution. A crosslinked powder was obtained from the crosslinked aqueous solution in the same manner as in Example 3. When the obtained crosslinked powder was made into a 2% by mass aqueous solution, a uniform aqueous solution was obtained.
  • a cross-linking agent aziridine derivative “PZ-33”
  • the shear viscosity of the aqueous solution was 137 mPa ⁇ s at a shear rate of 20 / s.
  • a negative electrode composition (slurry) was prepared in the same manner as in Example 7 except that the obtained crosslinked powder was used as a binder.
  • the solid content concentration was 55% by mass.
  • the obtained negative electrode composition was subjected to a long-term storage test in the same manner as in Example 1-1. Further, electrodes and batteries were prepared and evaluated in the same manner as in Examples 1-2 to 1-3 except that the obtained negative electrode composition was used.
  • the obtained negative electrode composition showed good long-term stability without any clear separation in the long-term storage test.
  • the peeling strength of the electrode was 195 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 91%.
  • Example 10 In Example 3, the concentration of the aqueous polymer solution to be crosslinked was set to 15% by mass, and as a crosslinking agent, the aziridine derivative "N, N'-hexamethylene-1,6-bis (1-)" was used instead of the aziridine derivative "PZ-33".
  • Aziridine carboxamide) (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., chemical structural formula is as follows) is crosslinked so as to be 9.5 parts by mass (5.6 mol%) with respect to 100 parts by mass of the polymer to be crosslinked.
  • a crosslinked aqueous solution was obtained in the same manner as in Example 3 except that the aqueous solution was dissolved in water so as to have a concentration of 10% by mass and heated at 80 ° C. for 16 hours. In the heating step, the crosslinked product became a non-fluid gel 2 hours after the start of heating, but by continuing heating, it became a fluid aqueous solution.
  • a crosslinked powder was obtained from the crosslinked aqueous solution in the same manner as in Example 3. When the obtained crosslinked powder was made into a 2% by mass aqueous solution, a uniform aqueous solution was obtained. The shear viscosity of the aqueous solution was 1290 mPa ⁇ s at a shear rate of 20 / s.
  • the obtained negative electrode composition was subjected to a long-term storage test in the same manner as in Example 1-1. Further, electrodes and batteries were prepared and evaluated in the same manner as in Examples 1-2 to 1-3 except that the obtained negative electrode composition was used.
  • the obtained negative electrode composition showed good long-term stability without any clear separation in the long-term storage test.
  • the peel strength of the electrode was 128 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 92%.
  • Example 10 since the ratio of SiO in the negative electrode composition is larger than that in Examples 1 to 9, the expansion and contraction of the electrode due to charging and discharging becomes large. That is, although it is a more difficult condition to maintain the battery characteristics, good results can be obtained in both the binding property and the battery characteristics.
  • Examples 7 to 10 had a relatively low viscosity, it was predicted that the force for holding the active material was small and the capacity retention rate would decrease accordingly, but the capacity retention rate was unexpectedly excellent. The reason for this is not clear, but in polymers whose viscosity has been adjusted after cross-linking, entanglement due to the partially cross-linked structure occurs, which follows the expansion and contraction of the active material, and the electrode structure is maintained even after the charge / discharge cycle. I guess it was because I was able to maintain it.
  • Example 11 In Example 3, the concentration of the aqueous solution of the crosslinked polymer was 20% by mass, and the crosslinking agent (aziridine derivative “PZ-33”) was 2.1 parts by mass (0.9 mol%) with respect to 100 parts by mass of the crosslinked polymer.
  • a crosslinked aqueous solution was obtained in the same manner as in Example 3 except that the mixture was heated at 90 ° C. for 14 hours. In the heating step, the crosslinked product became a non-fluid gel 2 hours after the start of heating, but by continuing heating, it became a fluid aqueous solution.
  • a crosslinked powder was obtained from the crosslinked aqueous solution in the same manner as in Example 3.
  • a negative electrode composition (slurry) was prepared in the same manner as in Example 10 except that the obtained crosslinked powder was used as a binder. The solid content concentration was 58% by mass.
  • the obtained negative electrode composition was subjected to a long-term storage test in the same manner as in Example 1-1. Further, electrodes and batteries were prepared and evaluated in the same manner as in Examples 1-2 to 1-3 except that the obtained negative electrode composition was used.
  • the obtained negative electrode composition showed relatively good long-term stability, although slight separation was observed in the long-term storage test.
  • the peeling strength of the electrode was 168 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 84%.
  • Example 12 In Example 3, the concentration of the aqueous solution of the crosslinked polymer is 20% by mass, and the amount of the aziridine derivative "PZ-33" as a crosslinking agent is 5 parts by mass (0.9 mol%) with respect to 100 parts by mass of the crosslinked polymer.
  • a crosslinked aqueous solution was obtained in the same manner as in Example 3 except that the mixture was heated at 90 ° C. for 14 hours. In the heating step, the crosslinked product became a non-fluid gel 2 hours after the start of heating, but by continuing heating, it became a fluid aqueous solution.
  • a crosslinked powder was obtained from the crosslinked aqueous solution in the same manner as in Example 3.
  • a negative electrode composition (slurry) was prepared in the same manner as in Example 10 except that the obtained crosslinked powder was used as a binder. The solid content concentration was 59% by mass.
  • the obtained negative electrode composition was subjected to a long-term storage test in the same manner as in Example 1-1. Further, electrodes and batteries were prepared and evaluated in the same manner as in Examples 1-2 to 1-3 except that the obtained negative electrode composition was used.
  • the obtained negative electrode composition showed relatively good long-term stability, although slight separation was observed in the long-term storage test.
  • the peeling strength of the electrode was 165 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 84%.
  • Example 13 As the cross-linking polymer, the same cross-linking polymer as in Example 2 and the same cross-linking polymer as in Example 3 were used at a mass ratio of 1: 1 and the concentration of the cross-linked polymer aqueous solution was 20% by mass, and the cross-linking agent was used.
  • the aziridine derivative "PZ-33" was added so as to be 5.2 parts by mass (0.9 mol%) with respect to 100 parts by mass of the polymer to be crosslinked, and heated at 90 ° C. for 8.5 hours to obtain an aqueous crosslinked product. .. In the heating step, the crosslinked product became a non-fluid gel 2 hours after the start of heating, but by continuing heating, it became a fluid aqueous solution.
  • a crosslinked powder was obtained from the crosslinked aqueous solution in the same manner as in Example 3.
  • the obtained crosslinked powder was made into a 2% by mass aqueous solution, a uniform aqueous solution was obtained.
  • the shear viscosity of the aqueous solution was 182.6 mPa ⁇ s at a shear rate of 20 / s.
  • a negative electrode composition (slurry) was prepared in the same manner as in Example 10 except that the obtained crosslinked powder was used as a binder. The solid content concentration was 58% by mass.
  • the obtained negative electrode composition was subjected to a long-term storage test in the same manner as in Example 1-1. Further, electrodes and batteries were prepared and evaluated in the same manner as in Examples 1-2 to 1-3 except that the obtained negative electrode composition was used.
  • the obtained negative electrode composition showed good long-term stability without any clear separation in the long-term storage test.
  • the peeling strength of the electrode was 183 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 82%.
  • Example 14 In a 20% by mass aqueous solution of the same crosslinked polymer as in Example 2, the same crosslinking agent (epoxy derivative, TMPTGE) as in Example 6 was added to 2.7 parts by mass (0.7 mol%) with respect to 100 parts by mass of the crosslinked polymer.
  • the crosslinked aqueous solution was obtained by heating at 90 ° C. for 79 hours. In the heating step, the crosslinked product became a non-fluid gel 2 hours after the start of heating, but by continuing heating, it became a fluid aqueous solution.
  • a crosslinked powder was obtained from the crosslinked aqueous solution in the same manner as in Example 3. When the obtained crosslinked powder was made into a 2% by mass aqueous solution, a uniform aqueous solution was obtained.
  • the shear viscosity of the aqueous solution was 158.8 mPa ⁇ s at a shear rate of 20 / s.
  • a negative electrode composition (slurry) was prepared in the same manner as in Example 10 except that the obtained crosslinked powder was used as a binder. The solid content concentration was 58% by mass.
  • the obtained negative electrode composition was subjected to a long-term storage test in the same manner as in Example 1-1. Further, electrodes and batteries were prepared and evaluated in the same manner as in Examples 1-2 to 1-3 except that the obtained negative electrode composition was used.
  • the obtained negative electrode composition showed good long-term stability without any clear separation in the long-term storage test.
  • the peel strength of the electrode was 212 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 85%.
  • Example 15 In a 20% by mass aqueous solution of the same crosslinked polymer as in Example 2, the same crosslinking agent (epoxy derivative, TMPTGE) as in Example 6 was added to 4.9 parts by mass (1.2 mol%) with respect to 100 parts by mass of the crosslinked polymer. To obtain an aqueous crosslinked product, the mixture was heated at 90 ° C. for 90.5 hours. In the heating step, the crosslinked product became a non-fluid gel 2 hours after the start of heating, but by continuing heating, it became a fluid aqueous solution. A crosslinked powder was obtained from the crosslinked aqueous solution in the same manner as in Example 3.
  • the same crosslinking agent epoxy derivative, TMPTGE
  • a negative electrode composition (slurry) was prepared in the same manner as in Example 10 except that the obtained crosslinked powder was used as a binder. The solid content concentration was 60% by mass.
  • the obtained negative electrode composition was subjected to a long-term storage test in the same manner as in Example 1-1. Further, electrodes and batteries were prepared and evaluated in the same manner as in Examples 1-2 to 1-3 except that the obtained negative electrode composition was used.
  • the obtained negative electrode composition showed good long-term stability without any clear separation in the long-term storage test.
  • the peel strength of the electrode was 238 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 83%.
  • Example 16 The same cross-linking agent as in Example 10 (aziridine derivative, N, N'-hexamethylene-1,6-bis (1-aziridine carboxamide)) was added to the same 20% by mass aqueous solution of the cross-linked polymer as in Example 2. Dissolve and add in water so that the amount is 2 parts by mass (0.6 mol%) with respect to 100 parts by mass, and the concentration of the crosslinked aqueous solution is 10% by mass, and heat at 90 ° C. for 9 hours for cross-linking. A body aqueous solution was obtained. In the heating step, the crosslinked product became a non-fluid gel 2 hours after the start of heating, but by continuing heating, it became a fluid aqueous solution.
  • aziridine derivative N, N'-hexamethylene-1,6-bis (1-aziridine carboxamide
  • a crosslinked powder was obtained from the crosslinked aqueous solution in the same manner as in Example 3.
  • the obtained crosslinked powder was made into a 2% by mass aqueous solution, a uniform aqueous solution was obtained.
  • the shear viscosity of the aqueous solution was 109.1 mPa ⁇ s at a shear rate of 20 / s.
  • the solid content mass ratio of graphite: SiO: binder 87.3: 9.7: 3 (mass ratio) without adding a conductive auxiliary agent (Denka Black).
  • a negative electrode composition (slurry) was prepared in the same manner as in Example 10 except that the mixture was mixed with. The solid content concentration was 59% by mass.
  • the obtained negative electrode composition was subjected to a long-term storage test in the same manner as in Example 1-1. Further, electrodes and batteries were prepared and evaluated in the same manner as in Examples 1-2 to 1-3 except that the obtained negative electrode composition was used.
  • the obtained negative electrode composition showed relatively good long-term stability, although slight separation was observed in the long-term storage test.
  • the peeling strength of the electrode was 195 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 86%.
  • Example 17 In a 20% by mass aqueous solution of the same crosslinked polymer as in Example 2, the aziridine derivative "PZ-33" was added as a crosslinking agent to 1.3 parts by mass (0.2 mol%) with respect to 100 parts by mass of the crosslinked polymer.
  • the crosslinked aqueous solution was obtained by heating at 90 ° C. for 9 hours. In the heating step, the crosslinked product became a non-fluid gel 1 hour after the start of heating, but by further heating, it became a fluid aqueous solution.
  • a crosslinked powder was obtained from the crosslinked aqueous solution in the same manner as in Example 3. When the obtained crosslinked powder was made into a 2% by mass aqueous solution, a uniform aqueous solution was obtained. The shear viscosity of the aqueous solution was 89.3 mPa ⁇ s at a shear rate of 20 / s.
  • a negative electrode composition (slurry) was prepared in the same manner as in Example 16 except that the obtained crosslinked powder was used as a binder. The solid content concentration was 58% by mass.
  • the obtained negative electrode composition was subjected to a long-term storage test in the same manner as in Example 1-1. Further, electrodes and batteries were prepared and evaluated in the same manner as in Examples 1-2 to 1-3 except that the obtained negative electrode composition was used.
  • the obtained negative electrode composition showed relatively good long-term stability, although slight separation was observed in the long-term storage test.
  • the peeling strength of the electrode was 183 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 89.7%.
  • Example 18 In a 20% by mass aqueous solution of the same crosslinked polymer as in Example 1, the aziridine derivative "PZ-33" was added as a crosslinking agent to 2.3 parts by mass (0.7 mol%) with respect to 100 parts by mass of the crosslinked polymer. In addition, it was heated at 90 ° C. for 24 hours to obtain a crosslinked aqueous solution. In the heating step, the crosslinked product became a non-fluid gel 2 hours after the start of heating, but by continuing heating, it became a fluid aqueous solution. A crosslinked powder was obtained from the crosslinked aqueous solution in the same manner as in Example 3.
  • a negative electrode composition (slurry) was prepared in the same manner as in Example 16 except that the obtained crosslinked powder was used as a binder. The solid content concentration was 58% by mass.
  • the obtained negative electrode composition was subjected to a long-term storage test in the same manner as in Example 1-1. Further, electrodes and batteries were prepared and evaluated in the same manner as in Examples 1-2 to 1-3 except that the obtained negative electrode composition was used.
  • the obtained negative electrode composition showed good long-term stability without any clear separation in the long-term storage test.
  • the peel strength of the electrode was 126 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 94%.
  • Example 19 A poly (acrylamide-sodium acrylate) copolymer (89 mol% of acrylamide, 11 mol% of acrylic acid and sodium acrylate, weight average molecular weight 585000, degree of neutralization 4%) was used as the polymer to be crosslinked.
  • the aziridine derivative "PZ-33" was added as a crosslinking agent to 5.8 parts by mass (1.0 mol%) with respect to 100 parts by mass of the crosslinked polymer, and the crosslinked product.
  • the aqueous solution was dissolved in water so as to have a concentration of 10% by mass, and heated at 90 ° C. for 1.5 hours to obtain a crosslinked aqueous solution.
  • a crosslinked powder was obtained from the crosslinked aqueous solution in the same manner as in Example 3.
  • the obtained crosslinked powder was made into a 2% by mass aqueous solution, a uniform aqueous solution was obtained.
  • the shear viscosity of the aqueous solution was 91.7 mPa ⁇ s at a shear rate of 20 / s.
  • a negative electrode composition (slurry) was prepared in the same manner as in Example 16 except that the obtained crosslinked powder was used as a binder. The solid content concentration was 58% by mass.
  • the obtained negative electrode composition was subjected to a long-term storage test in the same manner as in Example 1-1. Further, electrodes and batteries were prepared and evaluated in the same manner as in Examples 1-2 to 1-3 except that the obtained negative electrode composition was used.
  • the obtained negative electrode composition showed relatively good long-term stability, although slight separation was observed in the long-term storage test.
  • the peel strength of the electrode was 169 N / m, showing good binding properties.
  • the capacity retention rate of the battery was 92%.
  • the binder of the present invention can improve the long-term stability of the negative electrode composition and can contribute to the improvement of the binding property and the battery cycle characteristics. Further, when compared at the same viscosity, it is possible to provide a binder having higher binding properties and excellent battery characteristics, so that both handling characteristics and battery characteristics can be satisfied at the same time.
  • the present invention includes a configuration substantially the same as the configuration described in the embodiment (for example, a configuration having the same function, method and result, or a configuration having the same purpose and effect).
  • the present invention also includes a configuration in which a non-essential part of the configuration described in the above embodiment is replaced with another configuration.
  • the present invention also includes a configuration that exhibits the same action and effect as the configuration described in the above embodiment, or a configuration that can achieve the same object.
  • the present invention also includes a configuration in which a known technique is added to the configuration described in the above embodiment.
  • the binder for an electrochemical device according to the present invention can be used for various electrochemical devices.

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Abstract

Liant pour éléments électrochimiques, qui contient un corps réticulé qui est obtenu par réticulation d'un polymère au moyen d'un agent de réticulation ayant deux groupes fonctionnels ou plus qui sont réactifs avec un groupe carboxyle, ledit polymère ayant une ou plusieurs fractions choisies dans le groupe constitué par un groupe carboxyle et des sels de celui-ci et une ou plusieurs fractions choisies dans le groupe constitué par un groupe amide et une liaison amide.
PCT/JP2020/014986 2019-04-04 2020-04-01 Liant pour éléments électrochimiques WO2020204058A1 (fr)

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CN114614017A (zh) * 2022-03-24 2022-06-10 深圳市皓飞实业有限公司 粘结剂、负极极片以及锂离子电池

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WO2014065407A1 (fr) * 2012-10-26 2014-05-01 和光純薬工業株式会社 Liant pour une pile au lithium, composition pour produire une électrode et électrode
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