WO2020012941A1 - Power storage device composition, power storage device electrode slurry, power storage device electrode, and power storage device - Google Patents

Power storage device composition, power storage device electrode slurry, power storage device electrode, and power storage device Download PDF

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Publication number
WO2020012941A1
WO2020012941A1 PCT/JP2019/024999 JP2019024999W WO2020012941A1 WO 2020012941 A1 WO2020012941 A1 WO 2020012941A1 JP 2019024999 W JP2019024999 W JP 2019024999W WO 2020012941 A1 WO2020012941 A1 WO 2020012941A1
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Prior art keywords
storage device
mass
parts
repeating unit
power storage
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PCT/JP2019/024999
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French (fr)
Japanese (ja)
Inventor
卓哉 中山
香奈 増田
颯一 西條
有希 吉田
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Jsr株式会社
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Application filed by Jsr株式会社 filed Critical Jsr株式会社
Priority to JP2020530077A priority Critical patent/JP7220216B2/en
Priority to KR1020217000411A priority patent/KR20210028643A/en
Priority to CN201980045772.8A priority patent/CN112385060B/en
Publication of WO2020012941A1 publication Critical patent/WO2020012941A1/en

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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/62Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621Binders
    • H01M4/622Binders being polymers
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F257/00Macromolecular compounds obtained by polymerising monomers on to polymers of aromatic monomers as defined in group C08F12/00
    • C08F257/02Macromolecular compounds obtained by polymerising monomers on to polymers of aromatic monomers as defined in group C08F12/00 on to polymers of styrene or alkyl-substituted styrenes
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F279/00Macromolecular compounds obtained by polymerising monomers on to polymers of monomers having two or more carbon-to-carbon double bonds as defined in group C08F36/00
    • C08F279/02Macromolecular compounds obtained by polymerising monomers on to polymers of monomers having two or more carbon-to-carbon double bonds as defined in group C08F36/00 on to polymers of conjugated dienes
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01GCAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22Electrodes
    • H01G11/30Electrodes characterised by their material
    • H01G11/32Carbon-based
    • H01G11/38Carbon pastes or blends; Binders or additives therein
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01GCAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22Electrodes
    • H01G11/30Electrodes characterised by their material
    • H01G11/46Metal oxides
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01GCAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22Electrodes
    • H01G11/30Electrodes characterised by their material
    • H01G11/50Electrodes characterised by their material specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/13Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/13Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/13Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134Electrodes based on metals, Si or alloys
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/62Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries

Definitions

  • the present invention includes a composition for a power storage device, a slurry for a power storage device electrode containing the composition and an active material, a power storage device electrode formed by applying and drying the slurry on a current collector, and the electrode. Storage device.
  • An electrode used in such an electricity storage device is manufactured by applying a composition (slurry for an electrode) containing an active material and a polymer that functions as a binder to the surface of a current collector and drying the composition.
  • the properties required for the polymer used as a binder include the bonding ability between the active materials and the adhesion ability between the active material and the current collector, the abrasion resistance in the step of winding the electrode, the subsequent cutting, and the like. Examples include powder falling resistance in which fine powder of the active material does not fall off from the applied and dried composition coating film (hereinafter, also referred to as “active material layer”).
  • an active material using such a material having a large lithium storage capacity involves a large volume change due to insertion and extraction of lithium. For this reason, when a conventionally used electrode binder is applied to such a material having a large lithium occlusion amount, the active material may not be able to maintain the adhesion, and the active material may be peeled off. Large capacity reduction occurs.
  • Techniques for improving the adhesiveness of the electrode binder include a technique for controlling the surface acid content of the particulate binder particles (see Patent Documents 2 and 3), and a technique using an epoxy or hydroxy group-containing binder. Techniques for improving characteristics (see Patent Documents 4 and 5) have been proposed. In addition, a technique has been proposed in which the active material is bound by a rigid molecular structure of polyimide to suppress a change in volume of the active material (see Patent Document 6). A technique using a water-soluble polymer such as polyacrylic acid (see Patent Document 7) has also been proposed.
  • JP-A-2004-185810 International Publication No. 2011/096463 International Publication No. 2013/191080 JP 2010-205722 A JP 2010-3703 A JP 2011-204592 A WO 2015/099800
  • the electrode binders disclosed in Patent Documents 1 to 7 use a new active material typified by a silicon material having a large lithium occlusion amount and a large volume change due to occlusion / release of lithium.
  • the adhesiveness was not sufficient for the formation.
  • the electrode binder When such an electrode binder is used, the electrode deteriorates due to, for example, dropping of the active material due to repeated charging and discharging, and thus there has been a problem that the durability required for practical use cannot be sufficiently obtained.
  • some embodiments according to the present invention provide a composition for an electricity storage device that is excellent in flexibility and adhesion and that can produce an electricity storage device electrode exhibiting good charge / discharge durability characteristics. Some embodiments according to the present invention also provide a slurry for an electrode of a power storage device containing the composition. Further, some aspects of the present invention provide an electricity storage device electrode having excellent flexibility and adhesion, and exhibiting good charge / discharge durability characteristics. Further, some embodiments according to the present invention provide an electricity storage device having excellent charge / discharge durability characteristics.
  • the present invention has been made to solve at least a part of the problems described above, and can be realized as any of the following embodiments.
  • composition for an electricity storage device contains polymer particles (A) and a liquid medium (B),
  • the number average particle diameter of the polymer particles (A) is 50 nm or more and 500 nm or less;
  • the polymer particles (A) are: 1 to 50 parts by mass of a repeating unit (a1) derived from a conjugated diene compound, 5 to 90 parts by mass of a repeating unit (a2) derived from an unsaturated carboxylic acid, A repeating unit (a3) derived from (meth) acrylamide in an amount of 5 to 90 parts by mass,
  • the total amount of the repeating unit (a2) and the repeating unit (a3) is 50 parts by mass or more.
  • the pH can be between 6 and 11.
  • the 5% by mass aqueous dispersion of the polymer particles (A) at pH 9 may have a viscosity of 500 to 150,000 mPa ⁇ s.
  • the liquid medium (B) can be water.
  • composition for an electricity storage device electrode according to the present invention The composition for a power storage device according to any one of the above-described embodiments and an active material are included.
  • the active material may include a silicon material.
  • the slurry for the electricity storage device electrode may further contain at least one polymer selected from the group consisting of a styrene-butadiene copolymer, an acrylic polymer and a fluoropolymer.
  • Thickeners may be further included.
  • One embodiment of the electricity storage device electrode according to the present invention A current collector; and an active material layer formed by applying and drying the slurry for the power storage device electrode according to any one of the above aspects on the surface of the current collector.
  • One embodiment of the power storage device according to the present invention includes: The power storage device electrode of the above aspect is provided.
  • composition for an electric storage device since flexibility and adhesion can be improved, an electric storage device electrode exhibiting good charge / discharge durability characteristics can be manufactured.
  • the composition for a power storage device according to the present invention exerts the above effects particularly when the power storage device electrode contains a material having a large lithium storage capacity as an active material, for example, a carbon material such as graphite or a silicon material. That is, since a material having a large lithium storage capacity can be used as an active material, battery performance is also improved.
  • (meth) acrylic acid ⁇ is a concept that includes both “acrylic acid ⁇ ” and “methacrylic acid ⁇ ”.
  • ⁇ (meth) acrylate is a concept that includes both “ ⁇ acrylate” and “ ⁇ methacrylate”.
  • (meth) acrylamide” is a concept that includes both “acrylamide” and “methacrylamide”.
  • a numerical range described using “to” means that the numerical values described before and after “to” are included as the lower limit and the upper limit.
  • composition for electricity storage device contains polymer particles (A) and a liquid medium (B).
  • the composition for a power storage device according to the present embodiment is used for producing a power storage device electrode (active material layer) having improved binding ability between active materials, adhesion between an active material and a current collector, and powder drop resistance. It can be used as a material, or can be used as a material for forming a protective film for suppressing a short circuit caused by dendrite generated during charge and discharge.
  • active material layer active material layer having improved binding ability between active materials, adhesion between an active material and a current collector, and powder drop resistance. It can be used as a material, or can be used as a material for forming a protective film for suppressing a short circuit caused by dendrite generated during charge and discharge.
  • the composition for an electric storage device contains the polymer particles (A).
  • the polymer particles (A) are composed of a repeating unit (a1) derived from a conjugated diene compound (hereinafter simply referred to as a “repeating unit”).
  • (A1) ) 1 to 50 parts by mass, and 5 to 90 parts by mass of a repeating unit (a2) derived from an unsaturated carboxylic acid (hereinafter, also simply referred to as” repeating unit (a2) ").
  • a repeating unit (a3) derived from (meth) acrylamide (hereinafter, also simply referred to as “repeating unit (a3)”) in an amount of 5 to 90 parts by mass, and the repeating unit (a2) and the repeating unit (a3) Is 50 parts by mass or more.
  • the polymer particles (A) may contain a repeating unit derived from another monomer copolymerizable therewith, in addition to the above-mentioned repeating unit.
  • Examples of the other monomer include an unsaturated carboxylic acid ester having a hydroxyl group, an unsaturated carboxylic acid ester (however, excluding the unsaturated carboxylic acid ester having a hydroxyl group), an ⁇ , ⁇ -unsaturated nitrile compound, Examples thereof include a cationic monomer, an aromatic vinyl compound, and a compound having a sulfonic acid group.
  • the polymer particles (A) contained in the composition for an electric storage device according to the present embodiment are preferably in the form of a latex dispersed in a liquid medium (B).
  • the slurry for an electrode of an electricity storage device electrode hereinafter, simply referred to as “slurry” produced by mixing with the active material is stable. This is preferred because the coating properties are improved and the coating properties of the slurry on the current collector are improved.
  • the content ratio of the repeating unit (a1) derived from the conjugated diene compound is 1 to 50 parts by mass when the total of the repeating units contained in the polymer particles (A) is 100 parts by mass.
  • the lower limit of the content of the repeating unit (a1) is preferably 2 parts by mass, and more preferably 3 parts by mass.
  • the upper limit of the content ratio of the repeating unit (a1) is preferably 48 parts by mass, and more preferably 45 parts by mass.
  • the repeating unit (a1) When the repeating unit (a1) is contained in the above range, the dispersibility of the active material and the filler is improved, and a uniform active material layer and a protective film can be formed. High charge-discharge characteristics.
  • the polymer particles (A) coated on the surface of the active material can be imparted with elasticity, and the polymer particles (A) can be expanded and contracted to improve the adhesion. Show.
  • the conjugated diene compound is not particularly limited, but includes 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene and the like. And one or more selected from these. Among these, 1,3-butadiene is particularly preferred.
  • the content ratio of the repeating unit (a2) derived from the unsaturated carboxylic acid is 5 to 90 parts by mass when the total of repeating units contained in the polymer particles (A) is 100 parts by mass.
  • the lower limit of the content of the repeating unit (a2) is preferably 7 parts by mass, more preferably 10 parts by mass.
  • the upper limit for the content of the repeating unit (a2) is preferably 85 parts by mass, and more preferably 80 parts by mass.
  • unsaturated carboxylic acid examples include, but are not particularly limited to, acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, mono- or dicarboxylic acids such as itaconic acid, and one or more selected from these. be able to.
  • the content ratio of the repeating unit (a3) derived from (meth) acrylamide is 5 to 90 parts by mass when the total of the repeating units contained in the polymer particles (A) is 100 parts by mass.
  • the lower limit of the content of the repeating unit (a3) is preferably 7 parts by mass, and more preferably 10 parts by mass.
  • the upper limit of the content of the repeating unit (a3) is preferably 85 parts by mass, and more preferably 80 parts by mass.
  • the flexibility of the obtained active material layer becomes moderate, and the ability to adhere the current collector to the active material layer is improved. Furthermore, since the binding ability between active materials containing a carbon material and a silicon material such as graphite can be increased, the resulting active material layer has better flexibility and better adhesion to the current collector. .
  • the (meth) acrylamide is not particularly limited, but is acrylamide, methacrylamide, N-isopropylacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N-diethylmethacryl Amide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, N-methylol methacrylamide, N-methylol acrylamide, diacetone acrylamide, maleic amide, acrylamide tert-butyl sulfonic acid and the like. .
  • These (meth) acrylamides may be used alone or in combination of two or more.
  • the total amount of the repeating units (a2) and (a3) is 50 parts by mass or more, and 55 parts by mass. Parts by weight or more, more preferably 60 parts by weight or more.
  • the total amount of the repeating unit (a2) and the repeating unit (a3) is within the above range, the dispersibility of the active material and the filler becomes good, and the flexibility and the adhesion are improved. Is shown.
  • the polymer particles (A) may contain, in addition to the repeating units (a1) to (a3), a repeating unit derived from another monomer copolymerizable therewith.
  • a repeating unit examples include a repeating unit (a4) derived from an unsaturated carboxylic acid ester having a hydroxyl group (hereinafter, also simply referred to as “repeating unit (a4)”), an unsaturated carboxylic acid ester (provided that the hydroxyl group (A5) (hereinafter also simply referred to as “repeating unit (a5)”) derived from an ⁇ , ⁇ -unsaturated nitrile compound (a6).
  • repeating unit (a6) a repeating unit (a7) derived from an aromatic vinyl compound (hereinafter, also simply referred to as “repeating unit (a7)”), and a sulfonic acid group.
  • a repeating unit (a8) derived from a compound (hereinafter, also simply referred to as “repeating unit (a8)”), a repeating unit derived from a cationic monomer, and the like Is mentioned.
  • the unsaturated carboxylic acid ester having a hydroxyl group include, but are not particularly limited to, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl.
  • Examples include (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, glycerin mono (meth) acrylate, and glycerin di (meth) acrylate.
  • 2-hydroxyethyl (meth) acrylate and glycerin mono (meth) acrylate are preferred. These monomers can be used alone or in combination of two or more.
  • the unsaturated carboxylic acid ester is not particularly limited, but (meth) acrylic acid ester is preferable.
  • Specific examples of the (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, and n- (meth) acrylate.
  • methyl (meth) acrylate it is preferable to be at least one selected from methyl (meth) acrylate, ethyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, and particularly preferable is methyl (meth) acrylate. preferable.
  • ⁇ , ⁇ -unsaturated nitrile compound examples include, but are not particularly limited to, acrylonitrile, methacrylonitrile, ⁇ -chloroacrylonitrile, ⁇ -ethylacrylonitrile, vinylidene cyanide, and the like. It can be one or more. Among these, one or more selected from acrylonitrile and methacrylonitrile are preferable, and acrylonitrile is particularly preferable.
  • aromatic vinyl compound examples include, but are not particularly limited to, styrene, ⁇ -methylstyrene, p-methylstyrene, vinyltoluene, chlorostyrene, divinylbenzene, and the like. It can be more than a species. Of these, styrene is particularly preferred.
  • the compound having a sulfonic acid group include, but are not particularly limited to, vinyl sulfonic acid, styrene sulfonic acid, allyl sulfonic acid, sulfoethyl (meth) acrylate, sulfopropyl (meth) acrylate, sulfobutyl (meth) acrylate, Compounds having a sulfonic acid group such as acrylamido-2-methylpropanesulfonic acid, 2-hydroxy-3-acrylamidopropanesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, and alkali salts thereof may be used. .
  • the cationic monomer is not particularly limited, but is at least one monomer selected from the group consisting of a secondary amine (salt), a tertiary amine (salt), and a quaternary ammonium salt. Is preferred. Specific examples of these cationic monomers include, but are not particularly limited to, 2- (dimethylamino) ethyl (meth) acrylate, quaternary salt of dimethylaminoethyl (meth) acrylate methyl chloride, 2- (meth) acrylate (Diethylamino) ethyl, 3- (dimethylamino) propyl (meth) acrylate, 3- (diethylamino) propyl (meth) acrylate, 4- (dimethylamino) phenyl (meth) acrylate, 2- (meth) acrylate [(3,5-dimethylpyrazolyl) carbonylamino] ethyl, 2- (0- [1'-methyl
  • the polymer particle (A) has the repeating unit (a5), the repeating unit (a6), and the repeating unit (a7) when the total of the repeating units contained in the polymer particle (A) is 100 parts by mass. ), And the total amount of the repeating unit (a2) and the repeating unit (a2) is preferably from 5 to 50 parts by mass.
  • the polymer particles (A) contain the repeating unit in the above-described ratio, the dispersibility of the active material and the filler is improved, and the flexibility and adhesion are further improved.
  • the polymer particles (A) have the repeating unit (a2), the repeating unit (a3), and the repeating unit (a4) when the total of the repeating units contained in the polymer particles (A) is 100 parts by mass.
  • the repeating unit (a8) are preferably from 50 to 95 parts by mass, more preferably from 52 to 92 parts by mass, and particularly preferably from 55 to 90 parts by mass.
  • the polymer particles (A) have the repeating unit (a1), the repeating unit (a5), and the repeating unit (a6) when the total of the repeating units contained in the polymer particles (A) is 100 parts by mass.
  • the repeating unit (a7) are preferably 50 parts by mass or less, more preferably 5 to 48 parts by mass, and particularly preferably 8 to 45 parts by mass.
  • the number average particle diameter of the polymer particles (A) is 50 to 500 nm, preferably 60 to 450 nm, and more preferably 70 to 400 nm.
  • the polymer particles (A) are easily adsorbed on the surface of the active material, and thus the polymer particles (A) also move with the movement of the active material. It can follow and move. As a result, only one of the particles can be prevented from migrating alone, so that the deterioration of the electrical characteristics can be reduced.
  • the number average particle diameter of the polymer particles (A) can be calculated from the average value of 50 particle diameters obtained from an image of the polymer particles (A) observed by a transmission electron microscope (TEM).
  • TEM transmission electron microscope
  • Examples of the transmission electron microscope include “H-7650” manufactured by Hitachi High-Technologies Corporation.
  • the polymer particles (A) preferably have only one endothermic peak in a temperature range of 60 ° C. to 160 ° C. when measured by differential scanning calorimetry (DSC) according to JIS K7121.
  • the temperature of the endothermic peak ie, the glass transition temperature (Tg)
  • Tg glass transition temperature
  • the polymer particles (A) show good adhesion and have an active material layer. In contrast, better flexibility and adhesiveness can be imparted, which is preferable.
  • the method for producing the polymer particles (A) is not particularly limited. For example, emulsification performed in the presence of a known emulsifier (surfactant), a chain transfer agent, a polymerization initiator, or the like.
  • the polymerization method can be used.
  • the emulsifier (surfactant), chain transfer agent, and polymerization initiator compounds described in Japanese Patent No. 5999399 can be used.
  • the emulsion polymerization method for synthesizing the polymer particles (A) may be carried out by one-stage polymerization or by two-stage polymerization or more, but preferably by two-stage or more multi-stage polymerization.
  • the mixture of the above-mentioned monomers is preferably used in the presence of a suitable emulsifier, chain transfer agent, polymerization initiator and the like, preferably at 40 to 80 ° C. Can be by emulsion polymerization for 4 to 18 hours.
  • the ratio of the monomers used in the first-stage polymerization is calculated based on the total mass of the monomers (the sum of the mass of the monomers used in the first-stage polymerization and the mass of the monomers used in the second-stage polymerization). On the other hand, it is preferably in the range of 5 to 60% by mass, and more preferably in the range of 5 to 55% by mass.
  • the type of the monomer used for the first-stage polymerization and its use ratio and the type of the monomer used for the second-stage polymerization and its use ratio may be the same or different.
  • the polymerization conditions at each stage are preferably as follows from the viewpoint of the dispersibility of the obtained polymer particles (A).
  • First-stage polymerization preferably a temperature of 40 to 80 ° C .: preferably a polymerization time of 2 to 36 hours: a polymerization conversion rate of preferably 50% by mass or more, more preferably 60% by mass or more.
  • Second stage polymerization preferably at a temperature of 40 to 80 ° C .; preferably a polymerization time of 2 to 10 hours.
  • the polymerization reaction can proceed with good dispersion stability of the obtained polymer.
  • This total solid content concentration is preferably 45% by mass or less, and more preferably 40% by mass or less.
  • the pH is adjusted to 6 by adding a neutralizing agent to the polymerization mixture. It is preferably adjusted to about 11 to 11, preferably 7 to 11, and more preferably 7 to 10.
  • the neutralizing agent used here is not particularly limited, and examples thereof include metal hydroxides such as sodium hydroxide and potassium hydroxide; and ammonia.
  • the composition for an electric storage device according to the present embodiment contains a liquid medium (B).
  • the liquid medium (B) is preferably an aqueous medium containing water, and more preferably water.
  • the aqueous medium may contain a non-aqueous medium other than water. Examples of the non-aqueous medium include amide compounds, hydrocarbons, alcohols, ketones, esters, amine compounds, lactones, sulfoxides, and sulfone compounds. One or more selected from these are used. Can be.
  • the use of the aqueous medium as the liquid medium (B) in the composition for an electricity storage device according to the present embodiment reduces the degree of adverse effects on the environment and increases the safety for operators.
  • the content ratio of the non-aqueous medium contained in the aqueous medium is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and particularly preferably not substantially contained, in 100 parts by mass of the aqueous medium. preferable.
  • substantially not contained means that a non-aqueous medium is not intentionally added as a liquid medium, and a non-aqueous medium which is inevitably mixed when preparing a composition for an electricity storage device. May be included.
  • composition for an electricity storage device according to the present embodiment can contain additives other than the above-described components as necessary.
  • additives include polymers other than the polymer particles (A), preservatives, thickeners, and the like.
  • the composition for an electricity storage device may contain a polymer other than the polymer particles (A).
  • a polymer other than the polymer particles (A) examples include, but are not particularly limited to, SBR (styrene butadiene rubber) polymer, acrylic polymer containing unsaturated carboxylic acid ester or a derivative thereof as a constituent unit, PVDF (polyvinylidene fluoride), and the like. Fluorinated polymers and the like can be mentioned. These polymers may be used alone or in combination of two or more. By containing a polymer other than the polymer particles (A), flexibility and adhesion may be further improved.
  • the content ratio of the polymer particles (A) in the composition for an electricity storage device according to the present embodiment is such that the polymer particles (A), the polymers other than the polymer particles (A) contained as needed, and the thickener are included. Is preferably 10 to 90 parts by mass, more preferably 20 to 80 parts by mass, and particularly preferably 25 to 75 parts by mass with respect to 100 parts by mass of the total.
  • the composition for an electricity storage device according to the present embodiment may contain a preservative.
  • a preservative When the composition for an electricity storage device is stored by containing a preservative, it may be possible to suppress the growth of bacteria and fungi and the generation of foreign substances when the composition for an electricity storage device is stored.
  • preservatives include compounds described in Japanese Patent No. 5477610.
  • the composition for an electricity storage device according to the present embodiment may contain a thickener.
  • a thickener By containing a thickener, the applicability and the charge / discharge characteristics of the obtained electricity storage device may be further improved in some cases.
  • the thickener include cellulose compounds such as carboxymethylcellulose, methylcellulose, and hydroxypropylcellulose; poly (meth) acrylic acid; an ammonium salt or an alkali metal salt of the cellulose compound or the poly (meth) acrylic acid; Polyvinyl alcohol-based (co) polymers such as alcohols, modified polyvinyl alcohols and ethylene-vinyl alcohol copolymers; copolymers of vinyl esters with unsaturated carboxylic acids such as (meth) acrylic acid, maleic acid and fumaric acid Water-soluble polymers such as saponified products can be mentioned. Among these, alkali metal salts of carboxymethyl cellulose, alkali metal salts of poly (meth) acrylic acid and the like are preferable.
  • Examples of commercial products of these thickeners include alkali metal salts of carboxymethyl cellulose such as CMC1120, CMC1150, CMC2200, CMC2280, and CMC2450 (all manufactured by Daicel Corporation).
  • the content ratio of the thickener is 5 parts by mass or less based on 100 parts by mass of the total solid content of the composition for an electricity storage device. And more preferably 0.1 to 3 parts by mass.
  • composition for power storage device is, for example, a multi-stage or more multi-stage polymerization performed in the presence of a known emulsifier (surfactant), a chain transfer agent, a polymerization initiator, and the like. It can be produced by emulsion polymerization.
  • the composition for an electricity storage device is obtained by polymerizing a repeating unit group containing a repeating unit (a1) derived from a conjugated diene compound and a repeating unit (a2) derived from an unsaturated carboxylic acid.
  • the composition for an electric storage device obtained by the above-mentioned production method is preferably in the form of a latex dispersed in a liquid medium (B).
  • the composition for a power storage device is in the form of a latex dispersed in a liquid medium (B)
  • the stability of a slurry for a power storage device electrode prepared by mixing with an active material is improved, and the slurry is used as a current collector. Is preferable since the coating property of the resin becomes good.
  • the emulsifier include, for example, sulfates of higher alcohols, alkylbenzene sulfonates, alkyl diphenyl ether disulfonates, aliphatic sulfonates, aliphatic carboxylates, dehydroabietic acid salts, naphthalenesulfonic acid / formalin condensation
  • anionic surfactants such as sulfates of nonionic surfactants
  • nonionic surfactants such as alkyl esters of polyethylene glycol, alkylphenyl ethers of polyethylene glycol and alkyl ethers of polyethylene glycol
  • chain transfer agent examples include alkyl mercaptans such as n-hexyl mercaptan, n-octyl mercaptan, tert-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, and n-stearyl mercaptan; dimethyl xanthogen disulfide; Xanthogen compounds such as diisopropylxanthogen disulfide; thiuram compounds such as terpinolene, tetramethylthiuram disulfide, tetraethylthiuram disulfide and tetramethylthiuram monosulfide; 2,6-di-tert-butyl-4-methylphenol and styrenated phenol Phenolic compounds; allyl compounds such as allyl alcohol; halogenated carbons such as dichloromethane, dibromome
  • polymerization initiator examples include, for example, water-soluble polymerization initiators such as lithium persulfate, potassium persulfate, sodium persulfate, and ammonium persulfate; cumene hydroperoxide, benzoyl peroxide, tert-butyl hydroperoxide, acetyl Oil-soluble polymerization initiators such as peroxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, azobisisobutyronitrile, and 1,1'-azobis (cyclohexanecarbonitrile) Can be appropriately selected and used.
  • water-soluble polymerization initiators such as lithium persulfate, potassium persulfate, sodium persulfate, and ammonium persulfate
  • cumene hydroperoxide benzoyl peroxide
  • tert-butyl hydroperoxide tert-butyl hydroperoxide
  • potassium persulfate sodium persulfate
  • cumene hydroperoxide or tert-butyl hydroperoxide
  • a redox initiator combining an oxidizing agent and a reducing agent, such as the above-mentioned persulfate and sodium bisulfite.
  • the use ratio of the polymerization initiator is not particularly limited, but is appropriately set in consideration of the monomer composition, the pH of the polymerization reaction system, the combination of other additives, and the like.
  • composition for an electricity storage device can be produced by multistage emulsion polymerization of two or more stages, but is preferably performed by two or more stages of multistage polymerization.
  • the ratio of the monomers used in the first-stage polymerization is calculated based on the total mass of the monomers (the sum of the mass of the monomers used in the first-stage polymerization and the mass of the monomers used in the second-stage polymerization). On the other hand, it is preferably in the range of 5 to 60% by mass, and more preferably in the range of 5 to 55% by mass.
  • the type of the monomer used for the first-stage polymerization and its use ratio and the type of the monomer used for the second-stage polymerization and its use ratio may be the same or different.
  • the polymerization conditions at each stage are preferably as follows from the viewpoint of the dispersibility of the obtained composition for an electricity storage device.
  • First-stage polymerization preferably a temperature of 40 to 80 ° C .: preferably a polymerization time of 2 to 36 hours: a polymerization conversion rate of preferably 50% by mass or more, more preferably 60% by mass or more.
  • Second stage polymerization preferably at a temperature of 40 to 80 ° C .; preferably a polymerization time of 2 to 10 hours.
  • the polymerization reaction can proceed with good dispersion stability of the obtained polymer.
  • This total solid content concentration is preferably 45% by mass or less, and more preferably 40% by mass or less.
  • the pH can be adjusted to about 6 to 11, preferably 7 to 11, more preferably 7 to 10 by adding a neutralizing agent to the polymerization mixture after the completion of the emulsion polymerization.
  • the neutralizing agent used here is not particularly limited, and examples thereof include metal hydroxides such as sodium hydroxide and potassium hydroxide; and ammonia.
  • the composition for an electric storage device thus obtained can be made into a powder by removing the liquid medium (B).
  • a means for removing the liquid medium (B) in this case there is a method of drying and removing the liquid medium (B) by using a high-viscosity concentrator or a hot-air dryer.
  • the content ratio of the repeating unit (a1) derived from the conjugated diene compound is from 1 to 50 parts by mass when the total of all the repeating units contained in the composition for an electric storage device is 100 parts by mass. It is preferable that The lower limit of the content of the repeating unit (a1) is more preferably 2 parts by mass, and particularly preferably 3 parts by mass. The upper limit of the content of the repeating unit (a1) is more preferably 48 parts by mass, and particularly preferably 45 parts by mass.
  • the content of the repeating unit (a1) derived from the conjugated diene compound is from 0 to 10 parts by mass when the total of all repeating units contained in the composition for an electric storage device is 100 parts by mass. It is preferable that The upper limit of the content of the repeating unit (a1) is more preferably 5 parts by mass.
  • the repeating unit (a1) When the repeating unit (a1) is contained in the above range, the dispersibility of the active material and the filler is improved, and a uniform active material layer and a protective film can be formed. High charge-discharge characteristics.
  • the composition for an electricity storage device coated on the surface of the active material can be provided with elasticity, and the composition for an electricity storage device can be expanded and contracted to improve the adhesiveness, and thus exhibit good charge / discharge durability characteristics.
  • the conjugated diene compound is not particularly limited, but includes 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene and the like. And one or more selected from these. Among these, 1,3-butadiene is particularly preferred.
  • the content ratio of the repeating unit (a2) derived from the unsaturated carboxylic acid is 1 to 10 parts by mass when the total of all the repeating units contained in the composition for an electric storage device is 100 parts by mass. Part.
  • the lower limit of the content of the repeating unit (a2) is more preferably 2 parts by mass, and particularly preferably 3 parts by mass.
  • the content of the repeating unit (a2) derived from the unsaturated carboxylic acid is from 4 to 90 parts by mass when the total of all the repeating units contained in the composition for an electric storage device is 100 parts by mass.
  • the lower limit of the content of the repeating unit (a2) is more preferably 7 parts by mass, and particularly preferably 10 parts by mass.
  • the upper limit of the content of the repeating unit (a2) is more preferably 85 parts by mass, and particularly preferably 80 parts by mass.
  • the repeating unit (a2) in the above range By containing the repeating unit (a2) in the above range, the dispersibility of the active material and the filler is improved. Furthermore, by improving affinity with a silicon material as an active material and suppressing swelling of the silicon material, good charge / discharge durability is exhibited.
  • unsaturated carboxylic acid examples include, but are not particularly limited to, acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, mono- or dicarboxylic acids such as itaconic acid, and one or more selected from these. be able to.
  • the content of the repeating unit (a3) derived from (meth) acrylamide is from 5 to 90 parts by mass when the total of all the repeating units contained in the composition for an electric storage device is 100 parts by mass. Part.
  • the lower limit of the content of the repeating unit (a3) is more preferably 7 parts by mass, and particularly preferably 10 parts by mass.
  • the upper limit of the content of the repeating unit (a3) is more preferably 85 parts by mass, and particularly preferably 80 parts by mass.
  • the glass transition temperature (Tg) of the composition for an electric storage device becomes suitable.
  • the dispersibility of the active material and the filler is improved.
  • the flexibility of the obtained active material layer becomes moderate, and the ability to adhere the current collector to the active material layer is improved.
  • the binding ability between active materials containing a carbon material and a silicon material such as graphite can be increased, the obtained active material layer has better flexibility and adhesion ability to the current collector. .
  • the (meth) acrylamide is not particularly limited, but is acrylamide, methacrylamide, N-isopropylacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N-diethylmethacryl Amide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, N-methylol methacrylamide, N-methylol acrylamide, diacetone acrylamide, maleic amide, acrylamide tert-butyl sulfonic acid and the like. .
  • These (meth) acrylamides may be used alone or in combination of two or more.
  • the total amount of the repeating unit (a2) and the repeating unit (a3) is 50 parts by mass or more, and 55 parts by mass. Parts by weight or more, more preferably 60 parts by weight or more.
  • the total amount of the repeating unit (a2) and the repeating unit (a3) is within the above range, the dispersibility of the active material and the filler becomes good, and the flexibility and the adhesion are improved. Is shown.
  • the repeating unit group may include, in addition to the repeating units (a1), (a2), and (a3), It may contain a repeating unit derived from another copolymerizable monomer.
  • a repeating unit include a repeating unit (a4) derived from an unsaturated carboxylic acid ester having a hydroxyl group, and a repeating unit derived from an unsaturated carboxylic acid ester (excluding the unsaturated carboxylic acid ester having a hydroxyl group).
  • the unsaturated carboxylic acid ester having a hydroxyl group include, but are not particularly limited to, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl.
  • Examples include (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, glycerin mono (meth) acrylate, and glycerin di (meth) acrylate.
  • 2-hydroxyethyl (meth) acrylate and glycerin mono (meth) acrylate are preferred. These monomers can be used alone or in combination of two or more.
  • the unsaturated carboxylic acid ester is not particularly limited, but (meth) acrylic acid ester is preferable.
  • Specific examples of the (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, and n- (meth) acrylate.
  • methyl (meth) acrylate it is preferable to be at least one selected from methyl (meth) acrylate, ethyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, and particularly preferable is methyl (meth) acrylate. preferable.
  • ⁇ , ⁇ -unsaturated nitrile compound examples include, but are not particularly limited to, acrylonitrile, methacrylonitrile, ⁇ -chloroacrylonitrile, ⁇ -ethylacrylonitrile, vinylidene cyanide, and the like. It can be one or more. Among these, one or more selected from acrylonitrile and methacrylonitrile are preferable, and acrylonitrile is particularly preferable.
  • aromatic vinyl compound examples include, but are not particularly limited to, styrene, ⁇ -methylstyrene, p-methylstyrene, vinyltoluene, chlorostyrene, divinylbenzene, and the like. It can be more than a species. Of these, styrene is particularly preferred.
  • the compound having a sulfonic acid group include, but are not particularly limited to, vinyl sulfonic acid, styrene sulfonic acid, allyl sulfonic acid, sulfoethyl (meth) acrylate, sulfopropyl (meth) acrylate, sulfobutyl (meth) acrylate, Compounds having a sulfonic acid group such as acrylamido-2-methylpropanesulfonic acid, 2-hydroxy-3-acrylamidopropanesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, and alkali salts thereof may be used. .
  • the cationic monomer is not particularly limited, but is at least one monomer selected from the group consisting of a secondary amine (salt), a tertiary amine (salt), and a quaternary ammonium salt. Is preferred. Specific examples of these cationic monomers include, but are not particularly limited to, 2- (dimethylamino) ethyl (meth) acrylate, quaternary salt of dimethylaminoethyl (meth) acrylate methyl chloride, 2- (meth) acrylate (Diethylamino) ethyl, 3- (dimethylamino) propyl (meth) acrylate, 3- (diethylamino) propyl (meth) acrylate, 4- (dimethylamino) phenyl (meth) acrylate, 2- (meth) acrylate [(3,5-dimethylpyrazolyl) carbonylamino] ethyl, 2- (0- [1'-methyl
  • the total of all the repeating units contained in the composition for an electric storage device is 100 parts by mass, 1 selected from the group consisting of the repeating unit (a5), the repeating unit (a6), and the repeating unit (a7) It is preferable that the total amount of the seeds or more and the repeating unit (a2) is 5 to 50 parts by mass or more.
  • composition for power storage device 1.5.1. pH
  • the pH of the composition for an electricity storage device according to the present embodiment is preferably from 6 to 11, more preferably from 7 to 11, and particularly preferably from 7 to 10.5. If the pH is within the above range, it is possible to suppress the occurrence of problems such as insufficient leveling property and liquid dripping, and it is easy to manufacture an electric storage device electrode that has both good electrical characteristics and good adhesion. Become.
  • ⁇ " PH in this specification refers to physical properties measured as follows. This is a value measured at 25 ° C. using a pH meter using a glass electrode calibrated with a neutral phosphate standard solution and a borate standard solution as the pH standard solution in accordance with JIS Z8802: 2011. Examples of such a pH meter include “HM-7J” manufactured by Toa DK Corporation and “D-51” manufactured by Horiba, Ltd.
  • the pH of the composition for an electric storage device does not deny that the pH of the composition for an electric storage device is affected by the monomer composition constituting the polymer particles (A), but it is added that the pH is not determined only by the monomer composition. . That is, it is generally known that the pH of the composition for an electric storage device changes depending on polymerization conditions and the like even with the same monomer composition, and the examples in the specification of the present application show only one example. Absent.
  • the polymerization reaction solution is charged with all of the unsaturated carboxylic acid from the beginning, and then the other monomers are sequentially added and added, and the monomer other than the unsaturated carboxylic acid is added. Is added to the polymerization reaction solution, and the amount of carboxyl groups derived from the unsaturated carboxylic acid exposed on the surface of the obtained polymer is different from the case where the unsaturated carboxylic acid is finally added. It is considered that the pH of the composition for an electric storage device is greatly different only by changing the order of adding the monomers by the polymerization method.
  • the viscosity of the 5% by mass aqueous dispersion of the polymer particles (A) at pH 9 is preferably from 500 to 150,000 mPa ⁇ s, more preferably from 1,000 to 150,000 mPa ⁇ s, and It is particularly preferred that the viscosity is in the range of 2,000 to 150,000 mPa ⁇ s. It is preferable that the viscosity at pH 9 is equal to or higher than the lower limit, because the dispersibility of the active material and the filler becomes good and a uniform slurry can be prepared. It is preferable that the viscosity at pH 9 is equal to or less than the above upper limit because the dispersibility of the polymer particles (A) itself becomes good.
  • the viscosity of the 5% by mass aqueous dispersion of the polymer particles (A) is a value measured at a temperature of 25.0 ° C. using a B-type viscometer in accordance with JIS Z 8803.
  • a B-type viscometer for example, "RB-80L” or “TVB-10” manufactured by Toki Sangyo Co., Ltd. can be used.
  • the number average particle size of the composition for an electricity storage device according to the present embodiment is preferably 50 to 500 nm, more preferably 60 to 450 nm, and particularly preferably 70 to 400 nm.
  • the composition for a power storage device is easily adsorbed on the surface of the active material, so that the composition for a power storage device also moves following the movement of the active material. be able to.
  • only one of the particles can be prevented from migrating alone, so that the deterioration of the electrical characteristics can be reduced.
  • the number average particle diameter of the composition for a power storage device can be calculated from the average value of 50 particle diameters obtained from an image of the composition for a power storage device observed by a transmission electron microscope (TEM).
  • TEM transmission electron microscope
  • Examples of the transmission electron microscope include “H-7650” manufactured by Hitachi High-Technologies Corporation.
  • the composition for an electricity storage device according to the present embodiment has only one endothermic peak in a temperature range of 60 ° C. to 160 ° C. when measured by differential scanning calorimetry (DSC) according to JIS K7121. It is preferable that The temperature of the endothermic peak (ie, the glass transition temperature (Tg)) is more preferably in the range of 70 ° C. to 150 ° C.
  • Tg glass transition temperature
  • the composition for an electricity storage device shows good adhesion and also has a good adhesion to the active material layer. It is preferable because better flexibility and tackiness can be imparted.
  • the slurry for an electricity storage device according to the present embodiment contains the composition for an electricity storage device described above.
  • the composition for an electricity storage device according to the present embodiment can also be used as a material for forming a protective film for suppressing a short circuit caused by dendrite generated due to charge and discharge, It can also be used as a material for producing an electricity storage device electrode (active material layer) having improved binding ability between active materials, adhesion between the active material and the current collector, and powder drop resistance.
  • a slurry for an electricity storage device for forming a protective film (hereinafter, also referred to as a “slurry for forming a protection film”) and a slurry for an electricity storage device for forming an active material layer of an electrode for an electricity storage device (hereinafter, referred to as “storing electricity”) Also referred to as “device electrode slurry”).
  • slurry for forming a protective film refers to coating the slurry on the surface of the electrode or the separator or both and then drying it to form a protective film on the surface of the electrode or the separator or both. Refers to a dispersion used for forming.
  • the slurry for forming a protective film according to the present embodiment may be composed only of the above-described composition for a power storage device, or may further contain an inorganic filler.
  • each component contained in the protective film forming slurry according to the present embodiment will be described in detail. Note that the composition for a power storage device is as described above, and a description thereof will be omitted.
  • the protective film forming slurry according to the present embodiment can improve the toughness of the formed protective film by containing the inorganic filler.
  • the inorganic filler it is preferable to use at least one kind of particles selected from the group consisting of silica, titanium oxide (titania), aluminum oxide (alumina), zirconium oxide (zirconia), and magnesium oxide (magnesia).
  • titanium oxide and aluminum oxide are preferable from the viewpoint of further improving the toughness of the protective film.
  • rutile-type titanium oxide is more preferable.
  • the average particle size of the inorganic filler is preferably 1 ⁇ m or less, more preferably in the range of 0.1 to 0.8 ⁇ m.
  • the average particle size of the inorganic filler is preferably larger than the average pore size of the separator that is a porous membrane. Thereby, damage to the separator can be reduced, and it is possible to prevent the inorganic filler from clogging the micropores of the separator.
  • the slurry for forming a protective film according to the present embodiment preferably contains 0.1 to 20 parts by mass of the above-mentioned composition for an electric storage device in terms of solid content based on 100 parts by mass of the inorganic filler. More preferably, it is contained in an amount of up to 10 parts by mass.
  • the content ratio of the composition for a power storage device is in the above range, the balance between the toughness of the formed protective film and the permeability of lithium ions is improved, and as a result, the resistance increase rate of the obtained power storage device is lower. can do.
  • the material described in “1.2. Liquid Medium (B)” of the above-described composition for an electric storage device can be used as needed in the slurry for forming a protective film according to the present embodiment.
  • the amount of the liquid medium to be added can be adjusted as necessary so as to obtain the optimum viscosity of the slurry according to the coating method or the like.
  • the “slurry for power storage device electrode” in this specification is used to form an active material layer on the surface of the current collector by applying it to the surface of the current collector and then drying it. Refers to the resulting dispersion.
  • the slurry for an electricity storage device electrode according to the present embodiment contains the above-described composition for an electricity storage device and an active material.
  • the slurry for an electricity storage device electrode often contains a binder component such as an SBR-based copolymer and a thickener such as carboxymethyl cellulose in order to improve adhesion.
  • the slurry for an electricity storage device electrode according to the present embodiment can improve flexibility and adhesion even with only the polymer particles (A) described above.
  • the slurry for an electricity storage device electrode according to the present embodiment may contain a polymer other than the polymer particles (A) and a thickener in order to further improve the adhesion.
  • Polymer particles (A) The composition, characteristics, and production method of the polymer particles (A) are as described above, and thus description thereof is omitted.
  • the content ratio of the polymer particles (A) in the slurry for an electric storage device electrode according to the present embodiment is preferably 1 to 8 parts by mass, and more preferably 1 to 7 parts by mass with respect to 100 parts by mass of the active material. Is more preferably 1.5 to 6 parts by mass.
  • the content ratio of the polymer particles (A) is in the above range, the dispersibility of the active material in the slurry becomes good, and the applicability of the slurry becomes excellent.
  • the slurry for an electricity storage device electrode according to the present embodiment contains a polymer other than the polymer particles (A) and a thickener.
  • active material used in the slurry for an electricity storage device electrode according to the present embodiment include a carbon material, a silicon material, an oxide containing a lithium atom, a lead compound, a tin compound, an arsenic compound, an antimony compound, and an aluminum compound. Is mentioned. Specific examples of these include compounds described in Japanese Patent No. 5999399.
  • the active material layer may contain an active material exemplified below.
  • a conductive polymer such as polyacene; A X B Y O Z (where A is an alkali metal or a transition metal, B is at least one selected from transition metals such as cobalt, nickel, aluminum, tin, and manganese; Represents an oxygen atom, and X, Y and Z are numbers in the range of 1.10>X> 0.05, 4.00>Y> 0.85, 5.00>Z> 1.5.) And other metal oxides and the like.
  • the slurry for an electricity storage device electrode according to the present embodiment can be used when producing any of the electricity storage device electrodes of the positive electrode and the negative electrode, and is preferably used for both the positive electrode and the negative electrode.
  • Lithium iron phosphate has a fine primary particle size, and is known to be a secondary aggregate thereof. When charge and discharge are repeated, aggregation collapses in the active material layer and dissociation between the active materials occurs. This is considered to be one of the factors that peel off from the current collector and that the conductive network inside the active material layer is easily broken.
  • the power storage device electrode manufactured using the slurry for a power storage device electrode according to the present embodiment does not have the above-described problem even when lithium iron phosphate is used, and exhibits good electrical characteristics. be able to.
  • the reason for this is that the polymer particles (A) can bind lithium iron phosphate firmly, and at the same time, maintain the state in which lithium iron phosphate is firmly bound even during charge and discharge. It is thought that it is possible.
  • the active material when producing a negative electrode, it is preferable that the active material contains a silicon material among the active materials exemplified above. Since the silicon material has a large lithium storage capacity per unit weight as compared with other active materials, by containing the silicon material as the negative electrode active material, the storage capacity of the obtained power storage device can be increased, As a result, the output and energy density of the power storage device can be increased.
  • the negative electrode active material is a mixture of a silicon material and a carbon material. Since the change in volume of a carbon material due to charge and discharge is small, by using a mixture of a silicon material and a carbon material as a negative electrode active material, the effect of the volume change of the silicon material can be reduced, and the active material layer and the active material layer can be collected. The ability to adhere to the electric body can be further improved.
  • silicon (Si) When silicon (Si) is used as an active material, while silicon has a high capacity, a large volume change occurs when occluding lithium. For this reason, the silicon material has the property that it is pulverized, peeled from the current collector, or separated from the active materials due to repeated expansion and contraction, and the conductive network inside the active material layer is easily broken. As a result, the cycle characteristics are extremely deteriorated in a short time.
  • the electricity storage device electrode manufactured using the electricity storage device electrode slurry according to the present embodiment even when a silicon material is used, the above-described problem does not occur, and good electrical characteristics can be exhibited. it can. This is because the polymer particles (A) can firmly bind the silicon material, and the polymer particles (A) expand and contract even if the silicon material expands in volume by absorbing lithium. It is considered that the state in which the silicon material is firmly bound can be maintained.
  • the content ratio of the silicon material in 100% by mass of the active material is preferably 1% by mass or more, more preferably 1 to 50% by mass, still more preferably 5 to 45% by mass. It is particularly preferred that the content be set to 4040% by mass.
  • the content ratio of the silicon material in 100% by mass of the active material is within the above range, a power storage device having an excellent balance between improvement in output and energy density of the power storage device and charge / discharge durability characteristics can be obtained.
  • the active material preferably has a granular shape.
  • the average particle size of the active material is preferably from 0.1 to 100 ⁇ m, more preferably from 1 to 20 ⁇ m.
  • the average particle size of the active material is a volume average particle size calculated from the particle size distribution measured by a particle size distribution measuring device using a laser diffraction method as a measurement principle. Examples of such a laser diffraction type particle size distribution measuring apparatus include HORIBA @ LA-300 series and HORIBA @ LA-920 series (all manufactured by Horiba, Ltd.).
  • components may be added to the slurry for an electricity storage device electrode according to the present embodiment, if necessary.
  • Such components include, for example, polymers other than the polymer particles (A), thickeners, conductivity-imparting agents, liquid media (excluding carry-on components from the composition for power storage devices), pH adjusters, Corrosion inhibitors and the like.
  • the polymer other than the polymer particles (A) and the thickener may be selected from the compounds exemplified in the above “1.3.
  • Examples of the conductivity imparting agent include compounds described in Japanese Patent No. 5999399 and the like.
  • the liquid medium that can be additionally added to the slurry for an electricity storage device electrode according to the present embodiment may be the same as or different from the liquid medium (B) contained in the composition for an electricity storage device, It is preferable to use by selecting from the liquid media exemplified in “1.2. Liquid Medium (B)” above.
  • the usage ratio of the liquid medium (including the amount brought in from the power storage device composition) in the slurry for the power storage device electrode according to the present embodiment is determined by the solid content concentration in the slurry (total mass of components other than the liquid medium in the slurry). Is the ratio to the total mass of the slurry. The same applies hereinafter.) Is preferably 30 to 70% by mass, more preferably 40 to 60% by mass.
  • the slurry for a power storage device electrode according to the present embodiment can contain a pH adjuster or a corrosion inhibitor for the purpose of suppressing corrosion of the current collector according to the type of the active material.
  • pH adjusting agent examples include, for example, hydrochloric acid, phosphoric acid, sulfuric acid, acetic acid, formic acid, ammonium phosphate, ammonium sulfate, ammonium acetate, ammonium formate, ammonium chloride, sodium hydroxide, potassium hydroxide and the like. Sulfuric acid, ammonium sulfate, sodium hydroxide and potassium hydroxide are preferred. Further, it can be used by selecting from the compounds described in the method for producing the polymer particles (A).
  • ammonium metavanadate, sodium metavanadate, potassium metavanadate, ammonium metatungstate, sodium metatungstate, potassium metatungstate, ammonium paratungstate, sodium paratungstate, potassium paratungstate, molybdate examples thereof include ammonium, sodium molybdate, and potassium molybdate. Among these, ammonium paratungstate, ammonium metavanadate, sodium metavanadate, potassium metavanadate, and ammonium molybdate are preferable.
  • the slurry for power storage device electrode according to the present embodiment is manufactured by any method as long as it contains the above-described composition for power storage device and an active material. Alternatively, it can be manufactured by a method described in, for example, Japanese Patent No. 5999399.
  • the power storage device electrode according to the present embodiment includes a current collector, and an active material layer formed by applying and drying the above-described slurry for a power storage device electrode on the surface of the current collector. It is.
  • Such a power storage device electrode is formed by applying the above-mentioned slurry for a power storage device electrode to a surface of a current collector such as a metal foil to form a coating film, and then drying the coating film to form an active material layer. Can be manufactured.
  • the thus-produced power storage device electrode is obtained by binding the above-mentioned polymer particles (A), an active material, and an active material layer containing an optional component added as necessary to a current collector. Therefore, it is excellent in flexibility and adhesion, and shows good charge / discharge durability characteristics.
  • the current collector is not particularly limited as long as it is made of a conductive material, and examples thereof include a current collector described in Japanese Patent No. 5999399.
  • the electricity storage device electrode manufactured in this way has excellent flexibility and adhesion, and exhibits good charge / discharge durability.
  • the content ratio of the silicon element in 100 parts by mass of the active material layer is preferably 2 to 30 parts by mass, and preferably 2 to 20 parts by mass. More preferably, it is particularly preferably 3 to 10 parts by mass.
  • the content of the silicon element in the active material layer is within the above range, the power storage capacity of a power storage device manufactured using the same is improved, and an active material layer with a uniform distribution of the silicon element is obtained. .
  • the content of the silicon element in the active material layer can be measured, for example, by a method described in Japanese Patent No. 5999399.
  • the power storage device includes the above-described power storage device electrode, further contains an electrolytic solution, and can be manufactured using a component such as a separator according to a conventional method.
  • a component such as a separator according to a conventional method.
  • a specific manufacturing method for example, a negative electrode and a positive electrode are overlapped with a separator interposed therebetween, and this is wound in accordance with the shape of the battery, folded, stored in a battery container, and an electrolytic solution is injected into the battery container. And sealing.
  • the shape of the battery can be an appropriate shape such as a coin type, a cylindrical type, a square type, a laminate type, and the like.
  • the electrolyte may be liquid or gel, and may be selected from known electrolytes used for power storage devices that effectively exhibit the function as a battery, depending on the type of active material.
  • the electrolytic solution can be a solution in which the electrolyte is dissolved in a suitable solvent.
  • these electrolytes and solvents for example, compounds described in Japanese Patent No. 5999399 are exemplified.
  • composition for power storage device A power storage device composition containing polymer particles (A1) was obtained by two-stage polymerization as described below. First, in the first-stage polymerization, 220 parts by mass of water, 22 parts by mass of a monomer mixture composed of 8 parts by mass of 1,3-butadiene, 12 parts by mass of styrene, and 2 parts by mass of acrylic acid were put into a reactor, followed by chain transfer.
  • This graphite-coated silicon oxide is a conductive powder (active material) in which the surface of the silicon oxide is coated with graphite, the average particle diameter is 10.5 ⁇ m, and the obtained graphite-coated silicon oxide is 100% in total.
  • the ratio of the graphite coating in the case of mass% was 2 mass%.
  • the mixture was stirred for a time to obtain a paste.
  • Water was added to the obtained paste, the solid content concentration was adjusted to 48% by mass, and then, using a stirring defoaming machine (trade name “Awatori Neritaro”, manufactured by Shinky Corporation) at 200 rpm for 2 minutes.
  • a stirring defoaming machine trade name “Awatori Neritaro”, manufactured by Shinky Corporation
  • PVDF Polymer # 1120
  • conductive aid trade name "DENKA BLACK 50% pressed product” manufactured by Denka Corporation
  • 100 parts by mass of LiCoO 2 manufactured by Hayashi Kasei Co., Ltd.
  • NMP N-methylpyrrolidone
  • the slurry for positive electrode was prepared by stirring and mixing at 1,800 rpm for 5 minutes and further under reduced pressure (about 2.5 ⁇ 10 4 Pa) at 1,800 rpm for 1.5 minutes.
  • This positive electrode slurry was uniformly applied to the surface of the current collector made of aluminum foil by a doctor blade method so that the film thickness after solvent removal was 80 ⁇ m, and heated at 120 ° C. for 20 minutes to remove the solvent. .
  • a counter electrode positive electrode was obtained by pressing with a roll press machine so that the density of the active material layer was 3.0 g / cm 3 .
  • a lithium ion battery cell (power storage device) was assembled by mounting a positive electrode manufactured by punching out to a diameter of 16.16 mm, and closing the external body of the two-pole type coin cell with screws and sealing.
  • Capacity retention (%) (discharge capacity at 100th cycle) / (discharge capacity at 1st cycle) (Evaluation criteria) 5 points: capacity retention rate is 95% or more. 4 points: Capacity retention is 90% or more and less than 95%. 3 points: Capacity retention is 85% or more and less than 90%. 2 points: Capacity retention is 80% or more and less than 85%. 1 point: Capacity retention is 75% or more and less than 80%. 0 point: capacity retention is less than 75%.
  • “1C” indicates a current value at which a cell having a certain electric capacity is discharged at a constant current and discharge is completed in one hour.
  • “0.1 C” refers to a current value at which discharge is completed in 10 hours
  • “10 C” refers to a current value at which discharge is completed in 0.1 hours.
  • composition for power storage device (1) Preparation of composition for power storage device”, the type and amount of each monomer are described in Table 1 or Table 2 below, respectively.
  • a composition for an electricity storage device containing 20% by mass of a polymer component was obtained in the same manner as described above.
  • the polymer particles (A) obtained in Example 1 are referred to as “polymer particles (A1)”, and similarly, the polymer particles (A) obtained in Example 5 are referred to as “polymer particles (A)”.
  • the “polymer particles (A5)” and the polymer particles (A) obtained in Example 19 are referred to as “polymer particles (A19)” and the like.
  • the polymer particles obtained in Comparative Example 1 are referred to as “polymer particles (B1)”, and similarly, the polymer particles obtained in Comparative Example 9 are referred to as “polymer particles (B9)”. I do.
  • Example 2 in the same manner as in Example 1 except that the composition for an electricity storage device prepared above was used, a slurry for an electricity storage device electrode was prepared, and an electricity storage device electrode and an electricity storage device were prepared, respectively. Was evaluated in the same manner as described above.
  • Example 32 In the same manner as in Example 5, a composition for an electric storage device having a pH of 9.0 and containing 20% by mass of the polymer particles (A5) was obtained. Next, 1 mass of a thickener (trade name "CMC2200", manufactured by Daicel Co., Ltd.) was added as a first component to a twin-shaft planetary mixer (trade name "TK Hibismix 2P-03" manufactured by Primix Co., Ltd.). Parts (as solid content, added as an aqueous solution having a concentration of 2% by mass), and 1 part by mass of polymer particles (A5) (solids equivalent, containing 20% by mass of polymer particles (A5) obtained above).
  • a thickener trade name "CMC2200”, manufactured by Daicel Co., Ltd.
  • TK Hibismix 2P-03 manufactured by Primix Co., Ltd.
  • SBR (trade name “TRD105A”, manufactured by JSR Corporation) was added as an after-addition component in an amount corresponding to 2 parts by mass (solid content conversion value), and the mixture was further stirred for 1 hour to obtain a paste.
  • Water was added to the obtained paste, the solid content concentration was adjusted to 48% by mass, and then, using a stirring defoaming machine (trade name “Awatori Neritaro”, manufactured by Shinky Corporation) at 200 rpm for 2 minutes.
  • a stirring defoaming machine (trade name “Awatori Neritaro”, manufactured by Shinky Corporation) at 1800 rpm for 2 minutes.
  • An electricity storage device electrode and an electricity storage device were prepared in the same manner as in Example 1 except that the slurry for an electricity storage device electrode prepared above was used, and evaluated in the same manner as in Example 1.
  • Examples 27 to 31, 33 and Comparative Examples 11 to 17 Except that the composition of the slurry for the power storage device electrode was changed as shown in Table 3 below, slurry for the power storage device electrode was prepared in the same manner as in Example 32, and the power storage device electrode and the power storage device were produced. The same evaluation as for No. 32 was made.
  • a power storage device lithium ion secondary battery
  • these power storage device electrodes also has favorable charge / discharge rate characteristics.
  • the reason for this is that the electricity storage device electrodes according to Examples 1 to 26 shown in Table 1 and Table 2 reduce the change in the thickness of the active material layer due to charging and discharging as compared with Comparative Examples 1 to 10. It is presumed that the formation allows the conductive network inside the active material layer to be maintained.
  • the slurry for an electricity storage device electrode prepared using the composition for an electricity storage device according to the present invention shown in Examples 27 to 33 was the same as that of Comparative Examples 11 to 17.
  • active materials having a large volume change due to charge / discharge can be preferably bonded to each other, and furthermore, the adhesion between the active material layer and the current collector can be improved. It was found that the properties could be maintained well.
  • the present invention is not limited to the above embodiment, and various modifications are possible.
  • 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 object and effect).
  • the 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 invention also includes a configuration having the same function and effect as the configuration described in the above embodiment, or a configuration capable of achieving the same object.
  • the invention also includes a configuration obtained by adding a known technique to the configuration described in the above embodiment.

Abstract

Provided is a power storage device composition that has excellent flexibility and adhesive properties and makes it possible to produce a power storage device electrode that has favorable charge/discharge durability characteristics. This power storage device composition contains polymer particles (A) and a liquid medium (B). The number average particle size of the polymer particles (A) is 50–500 nm. When the total amount of repeating units included in the polymer particles (A) is taken to be 100 parts by mass, the polymer particles (A) contain 1–50 parts by mass of a repeating unit (a1) that is derived from a conjugated diene compound, 5–90 parts by mass of a repeating unit (a2) that is derived from an unsaturated carboxylic acid, and 5–90 parts by mass of a repeating unit (a3) that is derived from a (meth)acrylamide, the total amount of repeating unit (a2) and repeating unit (a3) being at least 50 parts by mass.

Description

蓄電デバイス用組成物、蓄電デバイス電極用スラリー、蓄電デバイス電極及び蓄電デバイスComposition for power storage device, slurry for power storage device electrode, power storage device electrode, and power storage device
 本発明は、蓄電デバイス用組成物、該組成物と活物質とを含有する蓄電デバイス電極用スラリー、該スラリーを集電体に塗布及び乾燥させて形成された蓄電デバイス電極、並びに該電極を備えた蓄電デバイスに関する。 The present invention includes a composition for a power storage device, a slurry for a power storage device electrode containing the composition and an active material, a power storage device electrode formed by applying and drying the slurry on a current collector, and the electrode. Storage device.
 近年、電子機器の駆動用電源として、高電圧かつ高エネルギー密度を有する蓄電デバイスが要求されている。このような蓄電デバイスとしては、リチウムイオン電池やリチウムイオンキャパシタなどが期待されている。 In recent years, a power storage device having a high voltage and a high energy density has been required as a power supply for driving electronic equipment. As such power storage devices, lithium ion batteries, lithium ion capacitors, and the like are expected.
 このような蓄電デバイスに使用される電極は、活物質と、バインダーとして機能する重合体とを含有する組成物(電極用スラリー)を集電体の表面へ塗布及び乾燥させることにより製造される。バインダーとして使用される重合体に要求される特性としては、活物質同士の結合能力及び活物質と集電体との密着能力、電極を巻き取る工程における耐擦性、その後の裁断などによっても、塗布・乾燥された組成物塗膜(以下、「活物質層」ともいう。)から活物質の微粉などが脱落しない粉落ち耐性などを挙げることができる。 電極 An electrode used in such an electricity storage device is manufactured by applying a composition (slurry for an electrode) containing an active material and a polymer that functions as a binder to the surface of a current collector and drying the composition. The properties required for the polymer used as a binder include the bonding ability between the active materials and the adhesion ability between the active material and the current collector, the abrasion resistance in the step of winding the electrode, the subsequent cutting, and the like. Examples include powder falling resistance in which fine powder of the active material does not fall off from the applied and dried composition coating film (hereinafter, also referred to as “active material layer”).
 なお、上記の活物質同士の結合能力及び活物質と集電体との密着能力、並びに粉落ち耐性については、性能の良否がほぼ比例関係にあることが経験上明らかになっている。従って本明細書では、以下、これらを包括して「密着性」という用語を用いて表す場合がある。 経 験 Experience has shown that the performance of the above-mentioned bonding ability between the active materials, the adhesion between the active material and the current collector, and the resistance to powder fall are almost proportional to each other. Accordingly, in the present specification, these may be hereinafter collectively represented by the term "adhesion".
 ところで最近になって、蓄電デバイスの高出力化及び高エネルギー密度化の要求を達成する観点から、リチウム吸蔵量の大きい材料を活物質として利用する検討が進められている。例えば、特許文献1に開示されているようにリチウムの理論吸蔵量が最大で約4,200mAh/gであるケイ素材料を活物質として活用する手法が有望視されている。 By the way, recently, from the viewpoint of achieving the demand for higher output and higher energy density of the electricity storage device, studies are being made on using a material having a large lithium storage capacity as an active material. For example, as disclosed in Patent Document 1, a technique utilizing a silicon material having a maximum theoretical storage amount of lithium of about 4,200 mAh / g as an active material is promising.
 しかしながら、このようなリチウム吸蔵量の大きい材料を利用した活物質は、リチウムの吸蔵・放出により大きな体積変化を伴う。このため、従来使用されている電極用バインダーを、このようなリチウム吸蔵量の大きい材料に適用すると、密着性を維持することができずに活物質が剥離するなどし、充放電に伴って顕著な容量低下が発生する。 However, an active material using such a material having a large lithium storage capacity involves a large volume change due to insertion and extraction of lithium. For this reason, when a conventionally used electrode binder is applied to such a material having a large lithium occlusion amount, the active material may not be able to maintain the adhesion, and the active material may be peeled off. Large capacity reduction occurs.
 電極用バインダーの密着性を改良するための技術としては、粒子状のバインダー粒子の表面酸量を制御する技術(特許文献2及び3参照)や、エポキシ基やヒドロキシ基を有するバインダーを用いて上記特性を向上させる技術(特許文献4及び5参照)などが提案されている。また、ポリイミドの剛直な分子構造で活物質を束縛し、活物質の体積変化を押さえ込もうとする技術(特許文献6参照)が提案されている。また、ポリアクリル酸のような水溶性ポリマーを用いる技術(特許文献7参照)も提案されている。 Techniques for improving the adhesiveness of the electrode binder include a technique for controlling the surface acid content of the particulate binder particles (see Patent Documents 2 and 3), and a technique using an epoxy or hydroxy group-containing binder. Techniques for improving characteristics (see Patent Documents 4 and 5) have been proposed. In addition, a technique has been proposed in which the active material is bound by a rigid molecular structure of polyimide to suppress a change in volume of the active material (see Patent Document 6). A technique using a water-soluble polymer such as polyacrylic acid (see Patent Document 7) has also been proposed.
特開2004-185810号公報JP-A-2004-185810 国際公開第2011/096463号International Publication No. 2011/096463 国際公開第2013/191080号International Publication No. 2013/191080 特開2010-205722号公報JP 2010-205722 A 特開2010-3703号公報JP 2010-3703 A 特開2011-204592号公報JP 2011-204592 A 国際公開第2015/098050号WO 2015/099800
 しかしながら、上記特許文献1~7に開示されているような電極用バインダーは、リチウム吸蔵量が大きく、しかもリチウムの吸蔵・放出に伴う体積変化が大きいケイ素材料に代表される新たな活物質を実用化するにあたり密着性が十分とは言えなかった。このような電極用バインダーを使用すると、充放電を繰り返すことにより活物質が脱落するなどして電極が劣化するため、実用化に必要な耐久性が十分に得られないという課題があった。 However, the electrode binders disclosed in Patent Documents 1 to 7 use a new active material typified by a silicon material having a large lithium occlusion amount and a large volume change due to occlusion / release of lithium. However, the adhesiveness was not sufficient for the formation. When such an electrode binder is used, the electrode deteriorates due to, for example, dropping of the active material due to repeated charging and discharging, and thus there has been a problem that the durability required for practical use cannot be sufficiently obtained.
 そこで、本発明に係る幾つかの態様は、柔軟性及び密着性に優れるとともに、良好な充放電耐久特性を示す蓄電デバイス電極を製造可能な蓄電デバイス用組成物を提供する。また、本発明に係る幾つかの態様は、該組成物を含有する蓄電デバイス電極用スラリーを提供する。また、本発明に係る幾つかの態様は、柔軟性及び密着性に優れるとともに、良好な充放電耐久特性を示す蓄電デバイス電極を提供する。さらに、本発明に係る幾つかの態様は、充放電耐久特性に優れる蓄電デバイスを提供する。 Therefore, some embodiments according to the present invention provide a composition for an electricity storage device that is excellent in flexibility and adhesion and that can produce an electricity storage device electrode exhibiting good charge / discharge durability characteristics. Some embodiments according to the present invention also provide a slurry for an electrode of a power storage device containing the composition. Further, some aspects of the present invention provide an electricity storage device electrode having excellent flexibility and adhesion, and exhibiting good charge / discharge durability characteristics. Further, some embodiments according to the present invention provide an electricity storage device having excellent charge / discharge durability characteristics.
 本発明は上述の課題の少なくとも一部を解決するためになされたものであり、以下のいずれかの態様として実現することができる。 The present invention has been made to solve at least a part of the problems described above, and can be realized as any of the following embodiments.
 本発明に係る蓄電デバイス用組成物の一態様は、
 重合体粒子(A)と、液状媒体(B)と、を含有し、
 前記重合体粒子(A)の数平均粒子径が50nm以上500nm以下であり、
 前記重合体粒子(A)中に含まれる繰り返し単位の合計を100質量部としたときに、前記重合体粒子(A)が、
 共役ジエン化合物に由来する繰り返し単位(a1)1~50質量部と、
 不飽和カルボン酸に由来する繰り返し単位(a2)5~90質量部と、
 (メタ)アクリルアミドに由来する繰り返し単位(a3)5~90質量部と、を含有し、
 前記繰り返し単位(a2)と前記繰り返し単位(a3)の合計量が50質量部以上である。
One embodiment of the composition for an electricity storage device according to the present invention,
It contains polymer particles (A) and a liquid medium (B),
The number average particle diameter of the polymer particles (A) is 50 nm or more and 500 nm or less;
When the total of the repeating units contained in the polymer particles (A) is 100 parts by mass, the polymer particles (A) are:
1 to 50 parts by mass of a repeating unit (a1) derived from a conjugated diene compound,
5 to 90 parts by mass of a repeating unit (a2) derived from an unsaturated carboxylic acid,
A repeating unit (a3) derived from (meth) acrylamide in an amount of 5 to 90 parts by mass,
The total amount of the repeating unit (a2) and the repeating unit (a3) is 50 parts by mass or more.
 前記蓄電デバイス用組成物の一態様において、
 pHが6~11であることができる。
In one embodiment of the composition for an electricity storage device,
The pH can be between 6 and 11.
 前記蓄電デバイス用組成物のいずれかの態様において、
 前記重合体粒子(A)の5質量%水分散液のpH9における粘度が、500~150,000mPa・sであることができる。
In any aspect of the composition for an electricity storage device,
The 5% by mass aqueous dispersion of the polymer particles (A) at pH 9 may have a viscosity of 500 to 150,000 mPa · s.
 前記蓄電デバイス用組成物のいずれかの態様において、
 前記液状媒体(B)が水であることができる。
In any aspect of the composition for an electricity storage device,
The liquid medium (B) can be water.
 本発明に係る蓄電デバイス電極用スラリーの一態様は、
 前記いずれかの態様の蓄電デバイス用組成物と、活物質と、を含有する。
One embodiment of the slurry for an electricity storage device electrode according to the present invention,
The composition for a power storage device according to any one of the above-described embodiments and an active material are included.
 前記蓄電デバイス電極用スラリーの一態様において、
 前記活物質としてケイ素材料を含有することができる。
In one embodiment of the slurry for the electricity storage device electrode,
The active material may include a silicon material.
 前記蓄電デバイス電極用スラリーのいずれかの態様において、
 スチレン-ブタジエン共重合体、アクリル系重合体及びフッ素系重合体からなる群より選択される少なくとも1種の重合体をさらに含有することができる。
In any aspect of the slurry for the electricity storage device electrode,
It may further contain at least one polymer selected from the group consisting of a styrene-butadiene copolymer, an acrylic polymer and a fluoropolymer.
 前記蓄電デバイス電極用スラリーのいずれかの態様において、
 増粘剤をさらに含有することができる。
In any aspect of the slurry for the electricity storage device electrode,
Thickeners may be further included.
 本発明に係る蓄電デバイス電極の一態様は、
 集電体と、前記集電体の表面上に前記いずれかの態様の蓄電デバイス電極用スラリーが塗布及び乾燥されて形成された活物質層と、を備える。
One embodiment of the electricity storage device electrode according to the present invention,
A current collector; and an active material layer formed by applying and drying the slurry for the power storage device electrode according to any one of the above aspects on the surface of the current collector.
 本発明に係る蓄電デバイスの一態様は、
 前記態様の蓄電デバイス電極を備える。
One embodiment of the power storage device according to the present invention includes:
The power storage device electrode of the above aspect is provided.
 本発明に係る蓄電デバイス用組成物によれば、柔軟性及び密着性を向上できるため、良好な充放電耐久特性を示す蓄電デバイス電極を製造することができる。本発明に係る蓄電デバイス用組成物は、蓄電デバイス電極が活物質としてリチウム吸蔵量の大きい材料、例えばグラファイトのような炭素材料やケイ素材料を含有する場合に特に上記の効果を発揮する。すなわち、活物質としてリチウム吸蔵量の大きい材料を使用できるので、電池性能も向上する。 According to the composition for an electric storage device according to the present invention, since flexibility and adhesion can be improved, an electric storage device electrode exhibiting good charge / discharge durability characteristics can be manufactured. The composition for a power storage device according to the present invention exerts the above effects particularly when the power storage device electrode contains a material having a large lithium storage capacity as an active material, for example, a carbon material such as graphite or a silicon material. That is, since a material having a large lithium storage capacity can be used as an active material, battery performance is also improved.
 以下、本発明に係る好適な実施形態について詳細に説明する。なお、本発明は、下記に記載された実施形態のみに限定されるものではなく、本発明の要旨を変更しない範囲において実施される各種の変形例も含むものとして理解されるべきである。なお、本明細書における「(メタ)アクリル酸~」とは、「アクリル酸~」及び「メタクリル酸~」の双方を包括する概念である。同様に「~(メタ)アクリレート」とは、「~アクリレート」及び「~メタクリレート」の双方を包括する概念である。同様に「(メタ)アクリルアミド」とは、「アクリルアミド」及び「メタクリルアミド」の双方を包括する概念である。 Hereinafter, preferred embodiments according to the present invention will be described in detail. It should be understood that the present invention is not limited to only the embodiments described below, but also includes various modifications that are made without departing from the spirit of the present invention. In this specification, “(meth) acrylic acid 酸” is a concept that includes both “acrylic acid ~” and “methacrylic acid ~”. Similarly, “~ (meth) acrylate” is a concept that includes both “~ acrylate” and “~ methacrylate”. Similarly, “(meth) acrylamide” is a concept that includes both “acrylamide” and “methacrylamide”.
 本明細書において、「~」を用いて記載された数値範囲は、「~」の前後に記載される数値を下限値及び上限値として含む意味である。 に お い て In this specification, a numerical range described using “to” means that the numerical values described before and after “to” are included as the lower limit and the upper limit.
 1.蓄電デバイス用組成物
 本実施形態に係る蓄電デバイス用組成物は、重合体粒子(A)と、液状媒体(B)とを含有する。本実施形態に係る蓄電デバイス用組成物は、活物質同士の結合能力及び活物質と集電体との密着能力並びに粉落ち耐性を向上させた蓄電デバイス電極(活物質層)を作製するための材料として使用することもできるし、充放電に伴って発生するデンドライトに起因する短絡を抑制するための保護膜を形成するための材料として使用することもできる。以下、本実施形態に係る蓄電デバイス用組成物に含まれる各成分について詳細に説明する。
1. Composition for electricity storage device The composition for electricity storage device according to the present embodiment contains polymer particles (A) and a liquid medium (B). The composition for a power storage device according to the present embodiment is used for producing a power storage device electrode (active material layer) having improved binding ability between active materials, adhesion between an active material and a current collector, and powder drop resistance. It can be used as a material, or can be used as a material for forming a protective film for suppressing a short circuit caused by dendrite generated during charge and discharge. Hereinafter, each component included in the composition for an electricity storage device according to the present embodiment will be described in detail.
 1.1.重合体粒子(A)
 本実施形態に係る蓄電デバイス用組成物は、重合体粒子(A)を含有する。重合体粒子(A)は、該重合体粒子(A)中に含まれる繰り返し単位の合計を100質量部としたときに、共役ジエン化合物に由来する繰り返し単位(a1)(以下、単に「繰り返し単位(a1)」ともいう。)1~50質量部と、不飽和カルボン酸に由来する繰り返し単位(a2)(以下、単に「繰り返し単位(a2)」ともいう。)5~90質量部と、(メタ)アクリルアミドに由来する繰り返し単位(a3)(以下、単に「繰り返し単位(a3)」ともいう。)5~90質量部と、を含有し、前記繰り返し単位(a2)と前記繰り返し単位(a3)の合計量が50質量部以上である。また、重合体粒子(A)は、前記繰り返し単位の他に、それと共重合可能な他の単量体に由来する繰り返し単位を含有してもよい。他の単量体としては、例えば、水酸基を有する不飽和カルボン酸エステル、不飽和カルボン酸エステル(ただし、前記水酸基を有する不飽和カルボン酸エステルを除く。)、α,β-不飽和ニトリル化合物、カチオン性単量体、芳香族ビニル化合物、スルホン酸基を有する化合物等が挙げられる。
1.1. Polymer particles (A)
The composition for an electric storage device according to the present embodiment contains the polymer particles (A). When the total of the repeating units contained in the polymer particles (A) is 100 parts by mass, the polymer particles (A) are composed of a repeating unit (a1) derived from a conjugated diene compound (hereinafter simply referred to as a “repeating unit”). (A1) ") 1 to 50 parts by mass, and 5 to 90 parts by mass of a repeating unit (a2) derived from an unsaturated carboxylic acid (hereinafter, also simply referred to as" repeating unit (a2) "). A repeating unit (a3) derived from (meth) acrylamide (hereinafter, also simply referred to as “repeating unit (a3)”) in an amount of 5 to 90 parts by mass, and the repeating unit (a2) and the repeating unit (a3) Is 50 parts by mass or more. Further, the polymer particles (A) may contain a repeating unit derived from another monomer copolymerizable therewith, in addition to the above-mentioned repeating unit. Examples of the other monomer include an unsaturated carboxylic acid ester having a hydroxyl group, an unsaturated carboxylic acid ester (however, excluding the unsaturated carboxylic acid ester having a hydroxyl group), an α, β-unsaturated nitrile compound, Examples thereof include a cationic monomer, an aromatic vinyl compound, and a compound having a sulfonic acid group.
 本実施形態に係る蓄電デバイス用組成物に含まれる重合体粒子(A)は、液状媒体(B)中に分散されたラテックス状であることが好ましい。重合体粒子(A)が液状媒体(B)中に分散されたラテックス状であると、活物質と混合して作製される蓄電デバイス電極用スラリー(以下、単に「スラリー」ともいう。)の安定性が良好となり、またスラリーの集電体への塗布性が良好となるため好ましい。 重合 The polymer particles (A) contained in the composition for an electric storage device according to the present embodiment are preferably in the form of a latex dispersed in a liquid medium (B). When the polymer particles (A) are in the form of a latex dispersed in the liquid medium (B), the slurry for an electrode of an electricity storage device electrode (hereinafter, simply referred to as “slurry”) produced by mixing with the active material is stable. This is preferred because the coating properties are improved and the coating properties of the slurry on the current collector are improved.
 以下、重合体粒子(A)を構成する各繰り返し単位、重合体粒子(A)の物性、製造方法の順に説明する。 Hereinafter, each repeating unit constituting the polymer particles (A), the physical properties of the polymer particles (A), and the production method will be described in this order.
 1.1.1.重合体粒子(A)を構成する各繰り返し単位
<共役ジエン化合物に由来する繰り返し単位(a1)>
 共役ジエン化合物に由来する繰り返し単位(a1)の含有割合は、重合体粒子(A)中に含まれる繰り返し単位の合計を100質量部としたときに、1~50質量部である。繰り返し単位(a1)の含有割合の下限としては、2質量部であることが好ましく、3質量部であることがより好ましい。繰り返し単位(a1)の含有割合の上限としては、48質量部であることが好ましく、45質量部であることがより好ましい。繰り返し単位(a1)を前記範囲で含有することにより、活物質やフィラーの分散性が良好となり、均一な活物質層や保護膜の作成が可能となるため、電極板の構造欠陥がなくなり、良好な充放電特性を示す。また、活物質の表面を被覆した重合体粒子(A)に伸縮性を付与することができ、重合体粒子(A)が伸縮することで密着性を向上できるので、良好な充放電耐久特性を示す。
1.1.1. Each repeating unit constituting polymer particles (A) <Repeating unit (a1) derived from conjugated diene compound>
The content ratio of the repeating unit (a1) derived from the conjugated diene compound is 1 to 50 parts by mass when the total of the repeating units contained in the polymer particles (A) is 100 parts by mass. The lower limit of the content of the repeating unit (a1) is preferably 2 parts by mass, and more preferably 3 parts by mass. The upper limit of the content ratio of the repeating unit (a1) is preferably 48 parts by mass, and more preferably 45 parts by mass. When the repeating unit (a1) is contained in the above range, the dispersibility of the active material and the filler is improved, and a uniform active material layer and a protective film can be formed. High charge-discharge characteristics. In addition, the polymer particles (A) coated on the surface of the active material can be imparted with elasticity, and the polymer particles (A) can be expanded and contracted to improve the adhesion. Show.
 共役ジエン化合物としては、特に限定されないが、1,3-ブタジエン、2-メチル-1,3-ブタジエン、2,3-ジメチル-1,3-ブタジエン、2-クロル-1,3-ブタジエンなどを挙げることができ、これらのうちから選択される1種以上であることができる。これらの中でも、1,3-ブタジエンが特に好ましい。 The conjugated diene compound is not particularly limited, but includes 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene and the like. And one or more selected from these. Among these, 1,3-butadiene is particularly preferred.
<不飽和カルボン酸に由来する繰り返し単位(a2)>
 不飽和カルボン酸に由来する繰り返し単位(a2)の含有割合は、重合体粒子(A)中に含まれる繰り返し単位の合計を100質量部としたときに、5~90質量部である。繰り返し単位(a2)の含有割合の下限としては、7質量部であることが好ましく、10質量部であることがより好ましい。繰り返し単位(a2)の含有割合の上限としては、85質量部であることが好ましく、80質量部であることがより好ましい。繰り返し単位(a2)を前記範囲で含有することにより、活物質やフィラーの分散性が良好となる。さらに、活物質としてのケイ素材料との親和性を向上させ、該ケイ素材料の膨潤を抑制することで良好な充放電耐久特性を示す。
<Repeating unit (a2) derived from unsaturated carboxylic acid>
The content ratio of the repeating unit (a2) derived from the unsaturated carboxylic acid is 5 to 90 parts by mass when the total of repeating units contained in the polymer particles (A) is 100 parts by mass. The lower limit of the content of the repeating unit (a2) is preferably 7 parts by mass, more preferably 10 parts by mass. The upper limit for the content of the repeating unit (a2) is preferably 85 parts by mass, and more preferably 80 parts by mass. By containing the repeating unit (a2) in the above range, the dispersibility of the active material and the filler is improved. Furthermore, by improving affinity with a silicon material as an active material and suppressing swelling of the silicon material, good charge / discharge durability is exhibited.
 不飽和カルボン酸としては、特に限定されないが、アクリル酸、メタクリル酸、クロトン酸、マレイン酸、フマル酸、イタコン酸等のモノまたはジカルボン酸を挙げることができ、これらから選択される一種以上であることができる。 Examples of the unsaturated carboxylic acid include, but are not particularly limited to, acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, mono- or dicarboxylic acids such as itaconic acid, and one or more selected from these. be able to.
<(メタ)アクリルアミドに由来する繰り返し単位(a3)>
 (メタ)アクリルアミドに由来する繰り返し単位(a3)の含有割合は、重合体粒子(A)中に含まれる繰り返し単位の合計を100質量部としたときに、5~90質量部である。繰り返し単位(a3)の含有割合の下限としては、7質量部であることが好ましく、10質量部であることがより好ましい。繰り返し単位(a3)の含有割合の上限としては、85質量部であることが好ましく、80質量部であることがより好ましい。繰り返し単位(a3)の含有割合が前記範囲内にあると、重合体粒子(A)のガラス転移温度(Tg)が好適となる。その結果、活物質やフィラーの分散性が良好となる。また、得られる活物質層の柔軟性が適度となり、集電体と活物質層との密着能力が良好となる。さらに、グラファイトのような炭素材料とケイ素材料を含有する活物質同士の結合能力を高めることができるため、得られる活物質層は、柔軟性や集電体に対する密着能力がより良好なものとなる。
<Repeating unit (a3) derived from (meth) acrylamide>
The content ratio of the repeating unit (a3) derived from (meth) acrylamide is 5 to 90 parts by mass when the total of the repeating units contained in the polymer particles (A) is 100 parts by mass. The lower limit of the content of the repeating unit (a3) is preferably 7 parts by mass, and more preferably 10 parts by mass. The upper limit of the content of the repeating unit (a3) is preferably 85 parts by mass, and more preferably 80 parts by mass. When the content of the repeating unit (a3) is within the above range, the glass transition temperature (Tg) of the polymer particles (A) becomes suitable. As a result, the dispersibility of the active material and the filler is improved. In addition, the flexibility of the obtained active material layer becomes moderate, and the ability to adhere the current collector to the active material layer is improved. Furthermore, since the binding ability between active materials containing a carbon material and a silicon material such as graphite can be increased, the resulting active material layer has better flexibility and better adhesion to the current collector. .
 (メタ)アクリルアミドとしては、特に限定されないが、アクリルアミド、メタクリルアミド、N-イソプロピルアクリルアミド、N,N-ジメチルアクリルアミド、N,N-ジメチルメタクリルアミド、N,N-ジエチルアクリルアミド、N,N-ジエチルメタクリルアミド、N,N-ジメチルアミノプロピルアクリルアミド、N,N-ジメチルアミノプロピルメタクリルアミド、N-メチロールメタクリルアミド、N-メチロールアクリルアミド、ジアセトンアクリルアミド、マレイン酸アミド、アクリルアミドtert-ブチルスルホン酸等が挙げられる。これらの(メタ)アクリルアミドは、1種単独で用いてもよく、2種以上を併用してもよい。 The (meth) acrylamide is not particularly limited, but is acrylamide, methacrylamide, N-isopropylacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N-diethylmethacryl Amide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, N-methylol methacrylamide, N-methylol acrylamide, diacetone acrylamide, maleic amide, acrylamide tert-butyl sulfonic acid and the like. . These (meth) acrylamides may be used alone or in combination of two or more.
 重合体粒子(A)中に含まれる繰り返し単位の合計を100質量部としたときに、前記繰り返し単位(a2)及び前記繰り返し単位(a3)の合計量は、50質量部以上であり、55質量部以上であることが好ましく、60質量部以上であることがより好ましい。前記繰り返し単位(a2)及び前記繰り返し単位(a3)の合計量が前記範囲であると、活物質やフィラーの分散性が良好となり、柔軟性や密着性が向上するため、良好な充放電耐久特性を示す。 When the total of the repeating units contained in the polymer particles (A) is 100 parts by mass, the total amount of the repeating units (a2) and (a3) is 50 parts by mass or more, and 55 parts by mass. Parts by weight or more, more preferably 60 parts by weight or more. When the total amount of the repeating unit (a2) and the repeating unit (a3) is within the above range, the dispersibility of the active material and the filler becomes good, and the flexibility and the adhesion are improved. Is shown.
<その他の繰り返し単位>
 重合体粒子(A)は、前記繰り返し単位(a1)~(a3)の他に、これらと共重合可能な他の単量体に由来する繰り返し単位を含有してもよい。このような繰り返し単位としては、水酸基を有する不飽和カルボン酸エステルに由来する繰り返し単位(a4)(以下、単に「繰り返し単位(a4)」ともいう。)、不飽和カルボン酸エステル(ただし、前記水酸基を有する不飽和カルボン酸エステルを除く。)に由来する繰り返し単位(a5)(以下、単に「繰り返し単位(a5)」ともいう。)、α,β-不飽和ニトリル化合物に由来する繰り返し単位(a6)(以下、単に「繰り返し単位(a6)」ともいう。)、芳香族ビニル化合物に由来する繰り返し単位(a7)(以下、単に「繰り返し単位(a7)」ともいう。)、スルホン酸基を有する化合物に由来する繰り返し単位(a8)(以下、単に「繰り返し単位(a8)」ともいう。)、カチオン性単量体に由来する繰り返し単位等が挙げられる。
<Other repeating units>
The polymer particles (A) may contain, in addition to the repeating units (a1) to (a3), a repeating unit derived from another monomer copolymerizable therewith. Examples of such a repeating unit include a repeating unit (a4) derived from an unsaturated carboxylic acid ester having a hydroxyl group (hereinafter, also simply referred to as “repeating unit (a4)”), an unsaturated carboxylic acid ester (provided that the hydroxyl group (A5) (hereinafter also simply referred to as “repeating unit (a5)”) derived from an α, β-unsaturated nitrile compound (a6). (Hereinafter, also simply referred to as “repeating unit (a6)”), a repeating unit (a7) derived from an aromatic vinyl compound (hereinafter, also simply referred to as “repeating unit (a7)”), and a sulfonic acid group. A repeating unit (a8) derived from a compound (hereinafter, also simply referred to as “repeating unit (a8)”), a repeating unit derived from a cationic monomer, and the like Is mentioned.
 水酸基を有する不飽和カルボン酸エステルの具体例としては、特に限定されないが、2-ヒドロキシエチル(メタ)アクリレート、2-ヒドロキシプロピル(メタ)アクリレート、3-ヒドロキシプロピル(メタ)アクリレート、4-ヒドロキシブチル(メタ)アクリレート、5-ヒドロキシペンチル(メタ)アクリレート、6-ヒドロキシヘキシル(メタ)アクリレート、グリセリンモノ(メタ)アクリレート、グリセリンジ(メタ)アクリレート等が挙げられる。これらの中でも、2-ヒドロキシエチル(メタ)アクリレート、グリセリンモノ(メタ)アクリレートが好ましい。なお、これらの単量体は、1種単独でまたは2種以上を組み合わせて用いることができる。 Specific examples of the unsaturated carboxylic acid ester having a hydroxyl group include, but are not particularly limited to, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl. Examples include (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, glycerin mono (meth) acrylate, and glycerin di (meth) acrylate. Among these, 2-hydroxyethyl (meth) acrylate and glycerin mono (meth) acrylate are preferred. These monomers can be used alone or in combination of two or more.
 不飽和カルボン酸エステルとしては、特に限定されないが、(メタ)アクリル酸エステルが好ましい。(メタ)アクリル酸エステルの具体例としては、(メタ)アクリル酸メチル、(メタ)アクリル酸エチル、(メタ)アクリル酸n-プロピル、(メタ)アクリル酸iso-プロピル、(メタ)アクリル酸n-ブチル、(メタ)アクリル酸iso-ブチル、(メタ)アクリル酸n-アミル、(メタ)アクリル酸iso-アミル、(メタ)アクリル酸ヘキシル、(メタ)アクリル酸シクロヘキシル、(メタ)アクリル酸2-エチルヘキシル、(メタ)アクリル酸n-オクチル、(メタ)アクリル酸ノニル、(メタ)アクリル酸デシル、ジ(メタ)アクリル酸エチレングリコール、ジ(メタ)アクリル酸プロピレングリコール、トリ(メタ)アクリル酸トリメチロールプロパン、テトラ(メタ)アクリル酸ペンタエリスリトール、ヘキサ(メタ)アクリル酸ジペンタエリスリトール、(メタ)アクリル酸アリルなどを挙げることができ、これらのうちから選択される1種以上であることができる。これらのうち、(メタ)アクリル酸メチル、(メタ)アクリル酸エチル及び(メタ)アクリル酸2-エチルヘキシルから選択される1種以上であることが好ましく、(メタ)アクリル酸メチルであることが特に好ましい。 The unsaturated carboxylic acid ester is not particularly limited, but (meth) acrylic acid ester is preferable. Specific examples of the (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, and n- (meth) acrylate. -Butyl, iso-butyl (meth) acrylate, n-amyl (meth) acrylate, iso-amyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acrylic acid 2 -Ethylhexyl, n-octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, tri (meth) acrylic acid Trimethylolpropane, pentaerythritol tetra (meth) acrylate, hexa (meth) a Acrylic acid dipentaerythritol can be mentioned (meth) allyl acrylate, can be at least one selected from among these. Among these, it is preferable to be at least one selected from methyl (meth) acrylate, ethyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, and particularly preferable is methyl (meth) acrylate. preferable.
 α,β-不飽和ニトリル化合物の具体例としては、特に限定されないが、アクリロニトリル、メタクリロニトリル、α-クロルアクリロニトリル、α-エチルアクリロニトリル、シアン化ビニリデン等を挙げることができ、これらから選択される1種以上であることができる。これらのうち、アクリロニトリル及びメタクリロニトリルから選択される1種以上であることが好ましく、アクリロニトリルであることが特に好ましい。 Specific examples of the α, β-unsaturated nitrile compound include, but are not particularly limited to, acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethylacrylonitrile, vinylidene cyanide, and the like. It can be one or more. Among these, one or more selected from acrylonitrile and methacrylonitrile are preferable, and acrylonitrile is particularly preferable.
 芳香族ビニル化合物の具体例としては、特に限定されないが、スチレン、α-メチルスチレン、p-メチルスチレン、ビニルトルエン、クロルスチレン、ジビニルベンゼン等を挙げることができ、これらのうちから選択される1種以上であることができる。これらのうち、スチレンであることが特に好ましい。 Specific examples of the aromatic vinyl compound include, but are not particularly limited to, styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, chlorostyrene, divinylbenzene, and the like. It can be more than a species. Of these, styrene is particularly preferred.
 スルホン酸基を有する化合物の具体例としては、特に限定されないが、ビニルスルホン酸、スチレンスルホン酸、アリルスルホン酸、スルホエチル(メタ)アクリレート、スルホプロピル(メタ)アクリレート、スルホブチル(メタ)アクリレート、2-アクリルアミド-2-メチルプロパンスルホン酸、2-ヒドロキシ-3-アクリルアミドプロパンスルホン酸、3-アリロキシ-2-ヒドロキシプロパンスルホン酸等のスルホン酸基を有する化合物、及びこれらのアルカリ塩などを用いてもよい。 Specific examples of the compound having a sulfonic acid group include, but are not particularly limited to, vinyl sulfonic acid, styrene sulfonic acid, allyl sulfonic acid, sulfoethyl (meth) acrylate, sulfopropyl (meth) acrylate, sulfobutyl (meth) acrylate, Compounds having a sulfonic acid group such as acrylamido-2-methylpropanesulfonic acid, 2-hydroxy-3-acrylamidopropanesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, and alkali salts thereof may be used. .
 カチオン性単量体としては、特に限定されないが、第二級アミン(塩)、第三級アミン(塩)及び第四級アンモニウム塩よりなる群から選択される少なくとも1種の単量体であることが好ましい。これらカチオン性単量体の具体例としては、特に限定されないが、(メタ)アクリル酸2-(ジメチルアミノ)エチル、ジメチルアミノエチル(メタ)アクリレート塩化メチル4級塩、(メタ)アクリル酸2-(ジエチルアミノ)エチル、(メタ)アクリル酸3-(ジメチルアミノ)プロピル、(メタ)アクリル酸3-(ジエチルアミノ)プロピル、(メタ)アクリル酸4-(ジメチルアミノ)フェニル、(メタ)アクリル酸2-[(3,5-ジメチルピラゾリル)カルボニルアミノ]エチル、(メタ)アクリル酸2-(0-[1’-メチルプロピリデンアミノ]カルボキシアミノ)エチル、(メタ)アクリル酸2-(1-アジリジニル)エチル、メタクロイルコリンクロリド、イソシアヌル酸トリス(2-アクリロイルオキシエチル)、2-ビニルピリジン、キナルジンレッド、1,2-ジ(2-ピリジル)エチレン、4’-ヒドラジノ-2-スチルバゾール二塩酸塩水和物、4-(4-ジメチルアミノスチリル)キノリン、1-ビニルイミダゾール、ジアリルアミン、ジアリルアミン塩酸塩、トリアリルアミン、ジアリルジメチルアンモニウムクロリド、ジクロルミド、N-アリルベンジルアミン、N-アリルアニリン、2,4-ジアミノ-6-ジアリルアミノ-1,3,5-トリアジン、N-trans-シンナミル-N-メチル-(1-ナフチルメチル)アミン塩酸塩、trans-N-(6,6-ジメチル-2-ヘプテン-4-イニル)-N-メチル-1-ナフチルメチルアミン塩酸塩等が挙げられる。これらの単量体は、1種単独で用いてもよく、2種以上を併用してもよい。 The cationic monomer is not particularly limited, but is at least one monomer selected from the group consisting of a secondary amine (salt), a tertiary amine (salt), and a quaternary ammonium salt. Is preferred. Specific examples of these cationic monomers include, but are not particularly limited to, 2- (dimethylamino) ethyl (meth) acrylate, quaternary salt of dimethylaminoethyl (meth) acrylate methyl chloride, 2- (meth) acrylate (Diethylamino) ethyl, 3- (dimethylamino) propyl (meth) acrylate, 3- (diethylamino) propyl (meth) acrylate, 4- (dimethylamino) phenyl (meth) acrylate, 2- (meth) acrylate [(3,5-dimethylpyrazolyl) carbonylamino] ethyl, 2- (0- [1'-methylpropylideneamino] carboxyamino) ethyl (meth) acrylate, 2- (1-aziridinyl) (meth) acrylate Ethyl, methacryloylcholine chloride, tris (2-acryloyloxyethyl) isocyanurate, 2 Vinylpyridine, quinaldine red, 1,2-di (2-pyridyl) ethylene, 4'-hydrazino-2-stilbazole dihydrochloride hydrate, 4- (4-dimethylaminostyryl) quinoline, 1-vinylimidazole, diallylamine , Diallylamine hydrochloride, triallylamine, diallyldimethylammonium chloride, dichlormide, N-allylbenzylamine, N-allylaniline, 2,4-diamino-6-diallylamino-1,3,5-triazine, N-trans-cinnamyl —N-methyl- (1-naphthylmethyl) amine hydrochloride, trans-N- (6,6-dimethyl-2-heptene-4-ynyl) -N-methyl-1-naphthylmethylamine hydrochloride, and the like. . These monomers may be used alone or in combination of two or more.
 重合体粒子(A)は、重合体粒子(A)中に含まれる繰り返し単位の合計を100質量部としたときに、前記繰り返し単位(a5)、前記繰り返し単位(a6)及び前記繰り返し単位(a7)からなる群より選ばれる1種以上と、前記繰り返し単位(a2)との合計量が、5~50質量部であることが好ましい。重合体粒子(A)が前記繰り返し単位を前記割合で含有することにより、活物質やフィラーの分散性が良好となり、柔軟性や密着性がさらに向上するため、良好な充放電耐久特性を示す。 The polymer particle (A) has the repeating unit (a5), the repeating unit (a6), and the repeating unit (a7) when the total of the repeating units contained in the polymer particle (A) is 100 parts by mass. ), And the total amount of the repeating unit (a2) and the repeating unit (a2) is preferably from 5 to 50 parts by mass. When the polymer particles (A) contain the repeating unit in the above-described ratio, the dispersibility of the active material and the filler is improved, and the flexibility and adhesion are further improved.
 重合体粒子(A)は、重合体粒子(A)中に含まれる繰り返し単位の合計を100質量部としたときに、前記繰り返し単位(a2)、前記繰り返し単位(a3)、前記繰り返し単位(a4)及び前記繰り返し単位(a8)の合計量が、50~95質量部であることが好ましく、52~92質量部であることがより好ましく、55~90質量部であることが特に好ましい。重合体粒子(A)が前記繰り返し単位を前記割合で含有することにより、活物質やフィラーの分散性が良好となり、柔軟性や密着性がさらに向上するため、良好な充放電耐久特性を示す。 The polymer particles (A) have the repeating unit (a2), the repeating unit (a3), and the repeating unit (a4) when the total of the repeating units contained in the polymer particles (A) is 100 parts by mass. ) And the repeating unit (a8) are preferably from 50 to 95 parts by mass, more preferably from 52 to 92 parts by mass, and particularly preferably from 55 to 90 parts by mass. When the polymer particles (A) contain the repeating unit in the above-described ratio, the dispersibility of the active material and the filler is improved, and the flexibility and adhesion are further improved.
 重合体粒子(A)は、重合体粒子(A)中に含まれる繰り返し単位の合計を100質量部としたときに、前記繰り返し単位(a1)、前記繰り返し単位(a5)、前記繰り返し単位(a6)及び前記繰り返し単位(a7)の合計量が50質量部以下であることが好ましく、5~48質量部であることがより好ましく、8~45質量部であることが特に好ましい。重合体粒子(A)が前記繰り返し単位を前記割合で含有することにより、活物質やフィラーの分散性が良好となり、柔軟性や密着性がさらに向上するため、良好な充放電耐久特性を示す。 The polymer particles (A) have the repeating unit (a1), the repeating unit (a5), and the repeating unit (a6) when the total of the repeating units contained in the polymer particles (A) is 100 parts by mass. ) And the repeating unit (a7) are preferably 50 parts by mass or less, more preferably 5 to 48 parts by mass, and particularly preferably 8 to 45 parts by mass. When the polymer particles (A) contain the repeating unit in the above-described ratio, the dispersibility of the active material and the filler is improved, and the flexibility and adhesion are further improved.
 1.1.2.重合体粒子(A)の物性
<数平均粒子径>
 重合体粒子(A)の数平均粒子径は、50~500nmであり、60~450nmであることが好ましく、70~400nmであることがより好ましい。重合体粒子(A)の数平均粒子径が前記範囲にあると、活物質の表面に重合体粒子(A)が吸着しやすくなるので、活物質の移動に伴って重合体粒子(A)も追従して移動することができる。その結果、両者の粒子のうちのいずれかのみが単独でマイグレーションすることを抑制できるので、電気的特性の劣化を低減することができる。
1.1.2. Physical properties of polymer particles (A) <number average particle diameter>
The number average particle diameter of the polymer particles (A) is 50 to 500 nm, preferably 60 to 450 nm, and more preferably 70 to 400 nm. When the number average particle diameter of the polymer particles (A) is in the above range, the polymer particles (A) are easily adsorbed on the surface of the active material, and thus the polymer particles (A) also move with the movement of the active material. It can follow and move. As a result, only one of the particles can be prevented from migrating alone, so that the deterioration of the electrical characteristics can be reduced.
 なお、重合体粒子(A)の数平均粒子径は、透過型電子顕微鏡(TEM)により観察した重合体粒子(A)の画像より得られる粒子径50個の平均値より算出することができる。透過型電子顕微鏡としては、例えば株式会社日立ハイテクノロジーズ製の「H-7650」などが挙げられる。 The number average particle diameter of the polymer particles (A) can be calculated from the average value of 50 particle diameters obtained from an image of the polymer particles (A) observed by a transmission electron microscope (TEM). Examples of the transmission electron microscope include “H-7650” manufactured by Hitachi High-Technologies Corporation.
<ガラス転移温度>
 重合体粒子(A)は、JIS K7121に準拠する示差走査熱量測定(DSC)によって測定したときに、60℃~160℃の温度範囲において吸熱ピークを1つのみ有するものであることが好ましい。この吸熱ピークの温度(すなわちガラス転移温度(Tg))は、70℃~150℃の範囲にあることがより好ましい。DSC分析における重合体粒子(A)の吸熱ピークが1つのみであり、かつ、該ピーク温度が前記範囲にある場合、重合体粒子(A)は良好な密着性を示すとともに、活物質層に対してより良好な柔軟性及び粘着性を付与することができ好ましい。
<Glass transition temperature>
The polymer particles (A) preferably have only one endothermic peak in a temperature range of 60 ° C. to 160 ° C. when measured by differential scanning calorimetry (DSC) according to JIS K7121. The temperature of the endothermic peak (ie, the glass transition temperature (Tg)) is more preferably in the range of 70 ° C. to 150 ° C. When the polymer particles (A) have only one endothermic peak in the DSC analysis and the peak temperature is within the above range, the polymer particles (A) show good adhesion and have an active material layer. In contrast, better flexibility and adhesiveness can be imparted, which is preferable.
 1.1.3.重合体粒子(A)の製造方法
 重合体粒子(A)の製造方法については、特に限定されないが、例えば公知の乳化剤(界面活性剤)、連鎖移動剤、重合開始剤などの存在下で行う乳化重合法によることができる。乳化剤(界面活性剤)、連鎖移動剤、重合開始剤としては、特許第5999399号公報等に記載された化合物を用いることができる。
1.1.3. Method for Producing Polymer Particles (A) The method for producing the polymer particles (A) is not particularly limited. For example, emulsification performed in the presence of a known emulsifier (surfactant), a chain transfer agent, a polymerization initiator, or the like. The polymerization method can be used. As the emulsifier (surfactant), chain transfer agent, and polymerization initiator, compounds described in Japanese Patent No. 5999399 can be used.
 重合体粒子(A)を合成するための乳化重合法は、一段重合で行ってもよく、二段重合以上の多段重合で行ってもよいが、二段以上の多段重合で行うことが好ましい。 乳化 The emulsion polymerization method for synthesizing the polymer particles (A) may be carried out by one-stage polymerization or by two-stage polymerization or more, but preferably by two-stage or more multi-stage polymerization.
 重合体粒子(A)の合成を一段重合によって行う場合、上記の単量体の混合物を、適当な乳化剤、連鎖移動剤、重合開始剤などの存在下で、好ましくは40~80℃において、好ましくは4~18時間の乳化重合によることができる。 When the synthesis of the polymer particles (A) is carried out by one-stage polymerization, the mixture of the above-mentioned monomers is preferably used in the presence of a suitable emulsifier, chain transfer agent, polymerization initiator and the like, preferably at 40 to 80 ° C. Can be by emulsion polymerization for 4 to 18 hours.
 重合体粒子(A)の合成を二段重合によって行う場合、各段階の重合は以下のように設定することが好ましい。 場合 When the synthesis of the polymer particles (A) is carried out by two-stage polymerization, it is preferable to set the polymerization in each stage as follows.
 一段目重合に使用する単量体の使用割合は、単量体の全質量(一段目重合に使用する単量体の質量と二段目重合に使用する単量体の質量との合計)に対して、5~60質量%の範囲とすることが好ましく、5~55質量%の範囲とすることがより好ましい。一段目重合をこのような単量体の使用割合で行うことにより、分散安定性に優れ、凝集物が生じ難い重合体粒子(A)の粒子を得ることができるとともに、蓄電デバイス用組成物の経時的な粘度上昇も抑制されることとなり好ましい。 The ratio of the monomers used in the first-stage polymerization is calculated based on the total mass of the monomers (the sum of the mass of the monomers used in the first-stage polymerization and the mass of the monomers used in the second-stage polymerization). On the other hand, it is preferably in the range of 5 to 60% by mass, and more preferably in the range of 5 to 55% by mass. By performing the first-stage polymerization with the use ratio of such a monomer, it is possible to obtain polymer particles (A) having excellent dispersion stability and hardly causing agglomerates, and to obtain a composition for an electricity storage device. This is preferable because the increase in viscosity over time is also suppressed.
 一段目重合に使用する単量体の種類及びその使用割合と、二段目重合に使用する単量体の種類及びその使用割合とは、同じであってもよく、異なっていてもよい。 (4) The type of the monomer used for the first-stage polymerization and its use ratio and the type of the monomer used for the second-stage polymerization and its use ratio may be the same or different.
 各段階の重合条件は、得られる重合体粒子(A)の分散性の観点から、以下のようにすることが好ましい。
・一段目重合;好ましくは40~80℃の温度:好ましくは2~36時間の重合時間:好ましくは50質量%以上、より好ましくは60質量%以上の重合転化率。
・二段目重合;好ましくは40~80℃の温度;好ましくは2~10時間の重合時間。
The polymerization conditions at each stage are preferably as follows from the viewpoint of the dispersibility of the obtained polymer particles (A).
First-stage polymerization; preferably a temperature of 40 to 80 ° C .: preferably a polymerization time of 2 to 36 hours: a polymerization conversion rate of preferably 50% by mass or more, more preferably 60% by mass or more.
Second stage polymerization; preferably at a temperature of 40 to 80 ° C .; preferably a polymerization time of 2 to 10 hours.
 乳化重合における全固形分濃度を50質量%以下とすることにより、得られる重合体の分散安定性が良好な状態で重合反応を進行させることができる。この全固形分濃度は、好ましくは45質量%以下であり、より好ましくは40質量%以下である。 (4) By setting the total solid content concentration in the emulsion polymerization to 50% by mass or less, the polymerization reaction can proceed with good dispersion stability of the obtained polymer. This total solid content concentration is preferably 45% by mass or less, and more preferably 40% by mass or less.
 重合体粒子(A)の合成を一段重合として行う場合であっても、二段重合法による場合であっても、乳化重合終了後には重合混合物に中和剤を添加することにより、pHを6~11程度、好ましくは7~11、より好ましくは7~10に調整することが好ましい。ここで使用する中和剤としては、特に限定されるものではないが、例えば水酸化ナトリウム、水酸化カリウムなどの金属水酸化物;アンモニアなどを挙げることができる。上記のpH範囲に設定することにより、重合体粒子(A)の安定性が良好となる。中和処理を行った後に、重合混合物を濃縮することにより、重合体粒子(A)の良好な安定性を維持しながら固形分濃度を高くすることができる。 Regardless of whether the synthesis of the polymer particles (A) is carried out as a one-stage polymerization or a two-stage polymerization method, after the emulsion polymerization is completed, the pH is adjusted to 6 by adding a neutralizing agent to the polymerization mixture. It is preferably adjusted to about 11 to 11, preferably 7 to 11, and more preferably 7 to 10. The neutralizing agent used here is not particularly limited, and examples thereof include metal hydroxides such as sodium hydroxide and potassium hydroxide; and ammonia. By setting the pH in the above range, the stability of the polymer particles (A) is improved. By concentrating the polymerization mixture after the neutralization treatment, the solid content concentration can be increased while maintaining good stability of the polymer particles (A).
 1.2.液状媒体(B)
 本実施形態に係る蓄電デバイス用組成物は、液状媒体(B)を含有する。液状媒体(B)としては、水を含有する水系媒体であることが好ましく、水であることがより好ましい。上記水系媒体には、水以外の非水系媒体を含有させることができる。この非水系媒体としては、例えばアミド化合物、炭化水素、アルコール、ケトン、エステル、アミン化合物、ラクトン、スルホキシド、スルホン化合物などを挙げることができ、これらの中から選択される1種以上を使用することができる。本実施形態に係る蓄電デバイス用組成物は、液状媒体(B)として水系媒体を使用することにより、環境に対して悪影響を及ぼす程度が低くなり、取扱作業者に対する安全性も高くなる。
1.2. Liquid medium (B)
The composition for an electric storage device according to the present embodiment contains a liquid medium (B). The liquid medium (B) is preferably an aqueous medium containing water, and more preferably water. The aqueous medium may contain a non-aqueous medium other than water. Examples of the non-aqueous medium include amide compounds, hydrocarbons, alcohols, ketones, esters, amine compounds, lactones, sulfoxides, and sulfone compounds. One or more selected from these are used. Can be. The use of the aqueous medium as the liquid medium (B) in the composition for an electricity storage device according to the present embodiment reduces the degree of adverse effects on the environment and increases the safety for operators.
 水系媒体中に含まれる非水系媒体の含有割合は、水系媒体100質量部中、10質量部以下であることが好ましく、5質量部以下であることがより好ましく、実質的に含有しないことが特に好ましい。ここで、「実質的に含有しない」とは、液状媒体として非水系媒体を意図的に添加しないという程度の意味であり、蓄電デバイス用組成物を調製する際に不可避的に混入する非水系媒体を含んでいてもよい。 The content ratio of the non-aqueous medium contained in the aqueous medium is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and particularly preferably not substantially contained, in 100 parts by mass of the aqueous medium. preferable. Here, "substantially not contained" means that a non-aqueous medium is not intentionally added as a liquid medium, and a non-aqueous medium which is inevitably mixed when preparing a composition for an electricity storage device. May be included.
 1.3.その他の添加剤
 本実施形態に係る蓄電デバイス用組成物は、必要に応じて上述した成分以外の添加剤を含有することができる。このような添加剤としては、例えば重合体粒子(A)以外の重合体、防腐剤、増粘剤等が挙げられる。
1.3. Other Additives The composition for an electricity storage device according to the present embodiment can contain additives other than the above-described components as necessary. Examples of such additives include polymers other than the polymer particles (A), preservatives, thickeners, and the like.
<重合体粒子(A)以外の重合体>
 本実施形態に係る蓄電デバイス用組成物は、重合体粒子(A)以外の重合体を含有してもよい。このような重合体としては、特に限定されないが、SBR(スチレンブタジエンゴム)系重合体、不飽和カルボン酸エステルまたはこれらの誘導体を構成単位として含むアクリル系重合体、PVDF(ポリフッ化ビニリデン)等のフッ素系重合体等が挙げられる。これらの重合体は、1種単独で用いてもよく、2種以上併用してもよい。重合体粒子(A)以外の重合体を含有することにより、柔軟性や密着性がより向上する場合がある。
<Polymer other than polymer particles (A)>
The composition for an electricity storage device according to the present embodiment may contain a polymer other than the polymer particles (A). Examples of such a polymer include, but are not particularly limited to, SBR (styrene butadiene rubber) polymer, acrylic polymer containing unsaturated carboxylic acid ester or a derivative thereof as a constituent unit, PVDF (polyvinylidene fluoride), and the like. Fluorinated polymers and the like can be mentioned. These polymers may be used alone or in combination of two or more. By containing a polymer other than the polymer particles (A), flexibility and adhesion may be further improved.
 本実施形態に係る蓄電デバイス用組成物における重合体粒子(A)の含有割合は、重合体粒子(A)、必要に応じて含有される重合体粒子(A)以外の重合体及び増粘剤の合計100質量部に対して、10~90質量部であることが好ましく、20~80質量部であることがより好ましく、25~75質量部であることが特に好ましい。 The content ratio of the polymer particles (A) in the composition for an electricity storage device according to the present embodiment is such that the polymer particles (A), the polymers other than the polymer particles (A) contained as needed, and the thickener are included. Is preferably 10 to 90 parts by mass, more preferably 20 to 80 parts by mass, and particularly preferably 25 to 75 parts by mass with respect to 100 parts by mass of the total.
<防腐剤>
 本実施形態に係る蓄電デバイス用組成物は、防腐剤を含有してもよい。防腐剤を含有することにより、蓄電デバイス用組成物を貯蔵した際に、細菌や黴などが増殖して異物が発生することを抑制できる場合がある。防腐剤の具体例としては、特許第5477610号公報等に記載された化合物が挙げられる。
<Preservative>
The composition for an electricity storage device according to the present embodiment may contain a preservative. When the composition for an electricity storage device is stored by containing a preservative, it may be possible to suppress the growth of bacteria and fungi and the generation of foreign substances when the composition for an electricity storage device is stored. Specific examples of preservatives include compounds described in Japanese Patent No. 5477610.
<増粘剤>
 本実施形態に係る蓄電デバイス用組成物は、増粘剤を含有してもよい。増粘剤を含有することにより、その塗布性や得られる蓄電デバイスの充放電特性等をさらに向上できる場合がある。
<Thickener>
The composition for an electricity storage device according to the present embodiment may contain a thickener. By containing a thickener, the applicability and the charge / discharge characteristics of the obtained electricity storage device may be further improved in some cases.
 増粘剤の具体例としては、例えばカルボキシメチルセルロース、メチルセルロース、ヒドロキシプロピルセルロース等のセルロース化合物;ポリ(メタ)アクリル酸;前記セルロース化合物又は前記ポリ(メタ)アクリル酸のアンモニウム塩もしくはアルカリ金属塩;ポリビニルアルコール、変性ポリビニルアルコール、エチレン-ビニルアルコール共重合体等のポリビニルアルコール系(共)重合体;(メタ)アクリル酸、マレイン酸、フマル酸等の不飽和カルボン酸とビニルエステルとの共重合体の鹸化物等の水溶性ポリマーを挙げることができる。これらの中でも、カルボキシメチルセルロースのアルカリ金属塩、ポリ(メタ)アクリル酸のアルカリ金属塩等が好ましい。 Specific examples of the thickener include cellulose compounds such as carboxymethylcellulose, methylcellulose, and hydroxypropylcellulose; poly (meth) acrylic acid; an ammonium salt or an alkali metal salt of the cellulose compound or the poly (meth) acrylic acid; Polyvinyl alcohol-based (co) polymers such as alcohols, modified polyvinyl alcohols and ethylene-vinyl alcohol copolymers; copolymers of vinyl esters with unsaturated carboxylic acids such as (meth) acrylic acid, maleic acid and fumaric acid Water-soluble polymers such as saponified products can be mentioned. Among these, alkali metal salts of carboxymethyl cellulose, alkali metal salts of poly (meth) acrylic acid and the like are preferable.
 これら増粘剤の市販品としては、例えばCMC1120、CMC1150、CMC2200、CMC2280、CMC2450(以上、株式会社ダイセル製)等のカルボキシメチルセルロースのアルカリ金属塩を挙げることができる。 市 販 Examples of commercial products of these thickeners include alkali metal salts of carboxymethyl cellulose such as CMC1120, CMC1150, CMC2200, CMC2280, and CMC2450 (all manufactured by Daicel Corporation).
 本実施形態に係る蓄電デバイス用組成物が増粘剤を含有する場合、増粘剤の含有割合は、蓄電デバイス用組成物の全固形分量100質量部に対して、5質量部以下であることが好ましく、0.1~3質量部であることがより好ましい。 When the composition for an electricity storage device according to the present embodiment contains a thickener, the content ratio of the thickener is 5 parts by mass or less based on 100 parts by mass of the total solid content of the composition for an electricity storage device. And more preferably 0.1 to 3 parts by mass.
 1.4.蓄電デバイス用組成物の製造方法
 本実施形態に係る蓄電デバイス用組成物は、例えば公知の乳化剤(界面活性剤)、連鎖移動剤、重合開始剤などの存在下で行う、二段重合以上の多段乳化重合により製造することができる。具体的には、上記蓄電デバイス用組成物は、共役ジエン化合物に由来する繰り返し単位(a1)と、不飽和カルボン酸に由来する繰り返し単位(a2)とを含む繰り返し単位群を重合して重合体粒子を得る第一工程と、前記重合体粒子の存在下、不飽和カルボン酸に由来する繰り返し単位(a2)と、(メタ)アクリルアミドに由来する繰り返し単位(a3)とを含む繰り返し単位群を重合する第二工程と、を含み、全繰り返し単位の合計を100質量部としたときに、前記繰り返し単位(a2)と前記繰り返し単位(a3)との合計量が50質量部以上とする方法により製造することができる。
1.4. Method for producing composition for power storage device The composition for power storage device according to the present embodiment is, for example, a multi-stage or more multi-stage polymerization performed in the presence of a known emulsifier (surfactant), a chain transfer agent, a polymerization initiator, and the like. It can be produced by emulsion polymerization. Specifically, the composition for an electricity storage device is obtained by polymerizing a repeating unit group containing a repeating unit (a1) derived from a conjugated diene compound and a repeating unit (a2) derived from an unsaturated carboxylic acid. A first step of obtaining particles, and polymerizing a repeating unit group containing a repeating unit (a2) derived from an unsaturated carboxylic acid and a repeating unit (a3) derived from (meth) acrylamide in the presence of the polymer particles. And a second step of performing the above, wherein the total amount of the repeating unit (a2) and the repeating unit (a3) is 50 parts by mass or more when the total of all the repeating units is 100 parts by mass. can do.
 上記の製造方法により得られた蓄電デバイス用組成物は、液状媒体(B)中に分散されたラテックス状であることが好ましい。蓄電デバイス用組成物が液状媒体(B)中に分散されたラテックス状であると、活物質と混合して作製される蓄電デバイス電極用スラリーの安定性が良好となり、またスラリーの集電体への塗布性が良好となるため好ましい。 電 The composition for an electric storage device obtained by the above-mentioned production method is preferably in the form of a latex dispersed in a liquid medium (B). When the composition for a power storage device is in the form of a latex dispersed in a liquid medium (B), the stability of a slurry for a power storage device electrode prepared by mixing with an active material is improved, and the slurry is used as a current collector. Is preferable since the coating property of the resin becomes good.
 乳化剤の具体例としては、例えば、高級アルコールの硫酸エステル塩、アルキルベンゼンスルホン酸塩、アルキルジフェニルエーテルジスルホン酸塩、脂肪族スルホン酸塩、脂肪族カルボン酸塩、デヒドロアビエチン酸塩、ナフタレンスルホン酸・ホルマリン縮合物、非イオン性界面活性剤の硫酸エステル塩などのアニオン性界面活性剤;ポリエチレングリコールのアルキルエステル、ポリエチレングリコールのアルキルフェニルエーテル、ポリエチレングリコールのアルキルエーテルなどのノニオン性界面活性剤;パーフルオロブチルスルホン酸塩、パーフルオロアルキル基含有リン酸エステル、パーフルオロアルキル基含有カルボン酸塩、パーフルオロアルキルエチレンオキシド付加物などのフッ素系界面活性剤などを挙げることができ、これらのうちから選択される一種以上を使用することができる。 Specific examples of the emulsifier include, for example, sulfates of higher alcohols, alkylbenzene sulfonates, alkyl diphenyl ether disulfonates, aliphatic sulfonates, aliphatic carboxylates, dehydroabietic acid salts, naphthalenesulfonic acid / formalin condensation Surfactants, anionic surfactants such as sulfates of nonionic surfactants; nonionic surfactants such as alkyl esters of polyethylene glycol, alkylphenyl ethers of polyethylene glycol and alkyl ethers of polyethylene glycol; perfluorobutyl sulfone Acid salts, perfluoroalkyl group-containing phosphates, perfluoroalkyl group-containing carboxylate salts, and fluorosurfactants such as perfluoroalkylethylene oxide adducts. , It can be used one or more selected from these.
 連鎖移動剤の具体例としては、例えば、n-ヘキシルメルカプタン、n-オクチルメルカプタン、tert-オクチルメルカプタン、n-ドデシルメルカプタン、tert-ドデシルメルカプタン、n-ステアリルメルカプタンなどのアルキルメルカプタン;ジメチルキサントゲンジサルファイド、ジイソプロピルキサントゲンジサルファイドなどのキサントゲン化合物;ターピノレン、テトラメチルチウラムジスルフィド、テトラエチルチウラムジスルフィド、テトラメチルチウラムモノスルフィドなどのチウラム化合物;2,6-ジ-tert-ブチル-4-メチルフェノール、スチレン化フェノールなどのフェノール化合物;アリルアルコールなどのアリル化合物;ジクロルメタン、ジブロモメタン、四臭化炭素などのハロゲン化炭化水素化合物;α-ベンジルオキシスチレン、α-ベンジルオキシアクリロニトリル、α-ベンジルオキシアクリルアミドなどのビニルエーテル化合物などのほか、トリフェニルエタン、ペンタフェニルエタン、アクロレイン、メタアクロレイン、チオグリコール酸、チオリンゴ酸、2-エチルヘキシルチオグリコレート、α-メチルスチレンダイマーなどを挙げることができ、これらのうちから選択される一種以上を使用することができる。 Specific examples of the chain transfer agent include alkyl mercaptans such as n-hexyl mercaptan, n-octyl mercaptan, tert-octyl mercaptan, n-dodecyl mercaptan, tert-dodecyl mercaptan, and n-stearyl mercaptan; dimethyl xanthogen disulfide; Xanthogen compounds such as diisopropylxanthogen disulfide; thiuram compounds such as terpinolene, tetramethylthiuram disulfide, tetraethylthiuram disulfide and tetramethylthiuram monosulfide; 2,6-di-tert-butyl-4-methylphenol and styrenated phenol Phenolic compounds; allyl compounds such as allyl alcohol; halogenated carbons such as dichloromethane, dibromomethane, carbon tetrabromide Hydrogen compounds; vinyl ether compounds such as α-benzyloxystyrene, α-benzyloxyacrylonitrile, α-benzyloxyacrylamide, etc., and triphenylethane, pentaphenylethane, acrolein, methacrolein, thioglycolic acid, thiomalic acid, 2- Ethylhexyl thioglycolate, α-methylstyrene dimer and the like can be mentioned, and one or more selected from these can be used.
 重合開始剤の具体例としては、例えば、過硫酸リチウム、過硫酸カリウム、過硫酸ナトリウム、過硫酸アンモニウムなどの水溶性重合開始剤;クメンハイドロパーオキサイド、過酸化ベンゾイル、tert-ブチルハイドロパーオキサイド、アセチルパーオキサイド、ジイソプロピルベンゼンハイドロパーオキサイド、1,1,3,3-テトラメチルブチルハイドロパーオキサイド、アゾビスイソブチロニトリル、1,1’-アゾビス(シクロヘキサンカルボニトリル)などの油溶性重合開始剤などを適宜選択して用いることができる。これらのうち、特に過硫酸カリウム、過硫酸ナトリウム、クメンハイドロパーオキサイドまたはtert-ブチルハイドロパーオキサイドを使用することが好ましい。また、上記過硫酸塩と重亜硫酸ナトリウムなどの、酸化剤と還元剤を組み合わせたレドックス開始剤を使用することも好ましい。重合開始剤の使用割合は特に制限されないが、単量体組成、重合反応系のpH、他の添加剤などの組み合わせなどを考慮して適宜設定される。 Specific examples of the polymerization initiator include, for example, water-soluble polymerization initiators such as lithium persulfate, potassium persulfate, sodium persulfate, and ammonium persulfate; cumene hydroperoxide, benzoyl peroxide, tert-butyl hydroperoxide, acetyl Oil-soluble polymerization initiators such as peroxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, azobisisobutyronitrile, and 1,1'-azobis (cyclohexanecarbonitrile) Can be appropriately selected and used. Among these, it is particularly preferable to use potassium persulfate, sodium persulfate, cumene hydroperoxide or tert-butyl hydroperoxide. It is also preferable to use a redox initiator combining an oxidizing agent and a reducing agent, such as the above-mentioned persulfate and sodium bisulfite. The use ratio of the polymerization initiator is not particularly limited, but is appropriately set in consideration of the monomer composition, the pH of the polymerization reaction system, the combination of other additives, and the like.
 上述のように、本実施形態に係る蓄電デバイス用組成物は、二段重合以上の多段乳化重合により製造することができるが、二段以上の多段重合で行うことが好ましい。 As described above, the composition for an electricity storage device according to the present embodiment can be produced by multistage emulsion polymerization of two or more stages, but is preferably performed by two or more stages of multistage polymerization.
 蓄電デバイス用組成物の製造を二段重合によって行う場合、各段階の重合は以下のように設定することが好ましい。 場合 When the production of the composition for an electric storage device is performed by two-stage polymerization, it is preferable to set the polymerization in each stage as follows.
 一段目重合に使用する単量体の使用割合は、単量体の全質量(一段目重合に使用する単量体の質量と二段目重合に使用する単量体の質量との合計)に対して、5~60質量%の範囲とすることが好ましく、5~55質量%の範囲とすることがより好ましい。一段目重合をこのような単量体の使用割合で行うことにより、分散安定性に優れ、凝集物が生じ難い重合体粒子を得ることができるとともに、蓄電デバイス用組成物の経時的な粘度上昇も抑制されることとなり好ましい。 The ratio of the monomers used in the first-stage polymerization is calculated based on the total mass of the monomers (the sum of the mass of the monomers used in the first-stage polymerization and the mass of the monomers used in the second-stage polymerization). On the other hand, it is preferably in the range of 5 to 60% by mass, and more preferably in the range of 5 to 55% by mass. By performing the first-stage polymerization with the use ratio of such a monomer, it is possible to obtain polymer particles having excellent dispersion stability and hardly causing agglomerates, and to increase the viscosity of the composition for an electricity storage device over time. Is also suppressed, which is preferable.
 一段目重合に使用する単量体の種類及びその使用割合と、二段目重合に使用する単量体の種類及びその使用割合とは、同じであってもよく、異なっていてもよい。 (4) The type of the monomer used for the first-stage polymerization and its use ratio and the type of the monomer used for the second-stage polymerization and its use ratio may be the same or different.
 各段階の重合条件は、得られる蓄電デバイス用組成物の分散性の観点から、以下のようにすることが好ましい。
・一段目重合;好ましくは40~80℃の温度:好ましくは2~36時間の重合時間:好ましくは50質量%以上、より好ましくは60質量%以上の重合転化率。
・二段目重合;好ましくは40~80℃の温度;好ましくは2~10時間の重合時間。
The polymerization conditions at each stage are preferably as follows from the viewpoint of the dispersibility of the obtained composition for an electricity storage device.
First-stage polymerization; preferably a temperature of 40 to 80 ° C .: preferably a polymerization time of 2 to 36 hours: a polymerization conversion rate of preferably 50% by mass or more, more preferably 60% by mass or more.
Second stage polymerization; preferably at a temperature of 40 to 80 ° C .; preferably a polymerization time of 2 to 10 hours.
 乳化重合における全固形分濃度を50質量%以下とすることにより、得られる重合体の分散安定性が良好な状態で重合反応を進行させることができる。この全固形分濃度は、好ましくは45質量%以下であり、より好ましくは40質量%以下である。 (4) By setting the total solid content concentration in the emulsion polymerization to 50% by mass or less, the polymerization reaction can proceed with good dispersion stability of the obtained polymer. This total solid content concentration is preferably 45% by mass or less, and more preferably 40% by mass or less.
 蓄電デバイス用組成物の製造において、乳化重合終了後には重合混合物に中和剤を添加することにより、pHを6~11程度、好ましくは7~11、より好ましくは7~10に調整することが好ましい。ここで使用する中和剤としては、特に限定されるものではないが、例えば水酸化ナトリウム、水酸化カリウムなどの金属水酸化物;アンモニアなどを挙げることができる。上記のpH範囲に調整することにより、蓄電デバイス用組成物の安定性が良好となる。また、中和処理を行った後に、重合混合物を濃縮することにより、蓄電デバイス用組成物の良好な安定性を維持しながら固形分濃度を高くすることができる。 In the production of the composition for an electric storage device, the pH can be adjusted to about 6 to 11, preferably 7 to 11, more preferably 7 to 10 by adding a neutralizing agent to the polymerization mixture after the completion of the emulsion polymerization. preferable. The neutralizing agent used here is not particularly limited, and examples thereof include metal hydroxides such as sodium hydroxide and potassium hydroxide; and ammonia. By adjusting the pH to the above range, the stability of the composition for an electricity storage device becomes good. In addition, by concentrating the polymerization mixture after the neutralization treatment, the solid content concentration can be increased while maintaining good stability of the composition for an electric storage device.
 このようにして得られた蓄電デバイス用組成物は、液状媒体(B)を除くことで粉体化させることもできる。この場合の液状媒体(B)を除く手段としては、高粘度濃縮機又は熱風乾燥機を使用することにより液状媒体(B)を乾燥させて除去する方法が挙げられる。 電 The composition for an electric storage device thus obtained can be made into a powder by removing the liquid medium (B). As a means for removing the liquid medium (B) in this case, there is a method of drying and removing the liquid medium (B) by using a high-viscosity concentrator or a hot-air dryer.
<共役ジエン化合物に由来する繰り返し単位(a1)>
 第一工程においては、共役ジエン化合物に由来する繰り返し単位(a1)の含有割合は、蓄電デバイス用組成物中に含まれる全繰り返し単位の合計を100質量部としたときに、1~50質量部であることが好ましい。繰り返し単位(a1)の含有割合の下限としては、2質量部であることがより好ましく、3質量部であることが特に好ましい。繰り返し単位(a1)の含有割合の上限としては、48質量部であることがより好ましく、45質量部であることが特に好ましい。
<Repeating unit (a1) derived from conjugated diene compound>
In the first step, the content ratio of the repeating unit (a1) derived from the conjugated diene compound is from 1 to 50 parts by mass when the total of all the repeating units contained in the composition for an electric storage device is 100 parts by mass. It is preferable that The lower limit of the content of the repeating unit (a1) is more preferably 2 parts by mass, and particularly preferably 3 parts by mass. The upper limit of the content of the repeating unit (a1) is more preferably 48 parts by mass, and particularly preferably 45 parts by mass.
 第二工程においては、共役ジエン化合物に由来する繰り返し単位(a1)の含有割合は、蓄電デバイス用組成物中に含まれる全繰り返し単位の合計を100質量部としたときに、0~10質量部であることが好ましい。繰り返し単位(a1)の含有割合の上限としては、5質量部であることがより好ましい。 In the second step, the content of the repeating unit (a1) derived from the conjugated diene compound is from 0 to 10 parts by mass when the total of all repeating units contained in the composition for an electric storage device is 100 parts by mass. It is preferable that The upper limit of the content of the repeating unit (a1) is more preferably 5 parts by mass.
 繰り返し単位(a1)を前記範囲で含有することにより、活物質やフィラーの分散性が良好となり、均一な活物質層や保護膜の作成が可能となるため、電極板の構造欠陥がなくなり、良好な充放電特性を示す。また、活物質の表面を被覆した蓄電デバイス用組成物に伸縮性を付与することができ、蓄電デバイス用組成物が伸縮することで密着性を向上できるので、良好な充放電耐久特性を示す。 When the repeating unit (a1) is contained in the above range, the dispersibility of the active material and the filler is improved, and a uniform active material layer and a protective film can be formed. High charge-discharge characteristics. In addition, the composition for an electricity storage device coated on the surface of the active material can be provided with elasticity, and the composition for an electricity storage device can be expanded and contracted to improve the adhesiveness, and thus exhibit good charge / discharge durability characteristics.
 共役ジエン化合物としては、特に限定されないが、1,3-ブタジエン、2-メチル-1,3-ブタジエン、2,3-ジメチル-1,3-ブタジエン、2-クロル-1,3-ブタジエンなどを挙げることができ、これらのうちから選択される1種以上であることができる。これらの中でも、1,3-ブタジエンが特に好ましい。 The conjugated diene compound is not particularly limited, but includes 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene and the like. And one or more selected from these. Among these, 1,3-butadiene is particularly preferred.
<不飽和カルボン酸に由来する繰り返し単位(a2)>
 第一工程においては、不飽和カルボン酸に由来する繰り返し単位(a2)の含有割合は、蓄電デバイス用組成物中に含まれる全繰り返し単位の合計を100質量部としたときに、1~10質量部であることが好ましい。繰り返し単位(a2)の含有割合の下限としては、2質量部であることがより好ましく、3質量部であることが特に好ましい。
<Repeating unit (a2) derived from unsaturated carboxylic acid>
In the first step, the content ratio of the repeating unit (a2) derived from the unsaturated carboxylic acid is 1 to 10 parts by mass when the total of all the repeating units contained in the composition for an electric storage device is 100 parts by mass. Part. The lower limit of the content of the repeating unit (a2) is more preferably 2 parts by mass, and particularly preferably 3 parts by mass.
 第二工程においては、不飽和カルボン酸に由来する繰り返し単位(a2)の含有割合は、蓄電デバイス用組成物中に含まれる全繰り返し単位の合計を100質量部としたときに、4~90質量部であることが好ましい。繰り返し単位(a2)の含有割合の下限としては、7質量部であることがより好ましく、10質量部であることが特に好ましい。繰り返し単位(a2)の含有割合の上限としては、85質量部であることがより好ましく、80質量部であることが特に好ましい。 In the second step, the content of the repeating unit (a2) derived from the unsaturated carboxylic acid is from 4 to 90 parts by mass when the total of all the repeating units contained in the composition for an electric storage device is 100 parts by mass. Part. The lower limit of the content of the repeating unit (a2) is more preferably 7 parts by mass, and particularly preferably 10 parts by mass. The upper limit of the content of the repeating unit (a2) is more preferably 85 parts by mass, and particularly preferably 80 parts by mass.
 繰り返し単位(a2)を前記範囲で含有することにより、活物質やフィラーの分散性が良好となる。さらに、活物質としてのケイ素材料との親和性を向上させ、該ケイ素材料の膨潤を抑制することで良好な充放電耐久特性を示す。 に よ り By containing the repeating unit (a2) in the above range, the dispersibility of the active material and the filler is improved. Furthermore, by improving affinity with a silicon material as an active material and suppressing swelling of the silicon material, good charge / discharge durability is exhibited.
 不飽和カルボン酸としては、特に限定されないが、アクリル酸、メタクリル酸、クロトン酸、マレイン酸、フマル酸、イタコン酸等のモノまたはジカルボン酸を挙げることができ、これらから選択される一種以上であることができる。 Examples of the unsaturated carboxylic acid include, but are not particularly limited to, acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, mono- or dicarboxylic acids such as itaconic acid, and one or more selected from these. be able to.
<(メタ)アクリルアミドに由来する繰り返し単位(a3)>
 第二工程においては、(メタ)アクリルアミドに由来する繰り返し単位(a3)の含有割合は、蓄電デバイス用組成物中に含まれる全繰り返し単位の合計を100質量部としたときに、5~90質量部であることが好ましい。繰り返し単位(a3)の含有割合の下限としては、7質量部であることがより好ましく、10質量部であることが特に好ましい。繰り返し単位(a3)の含有割合の上限としては、85質量部であることがより好ましく、80質量部であることが特に好ましい。
<Repeating unit (a3) derived from (meth) acrylamide>
In the second step, the content of the repeating unit (a3) derived from (meth) acrylamide is from 5 to 90 parts by mass when the total of all the repeating units contained in the composition for an electric storage device is 100 parts by mass. Part. The lower limit of the content of the repeating unit (a3) is more preferably 7 parts by mass, and particularly preferably 10 parts by mass. The upper limit of the content of the repeating unit (a3) is more preferably 85 parts by mass, and particularly preferably 80 parts by mass.
 繰り返し単位(a3)の含有割合が前記範囲内にあると、蓄電デバイス用組成物のガラス転移温度(Tg)が好適となる。その結果、活物質やフィラーの分散性が良好となる。また、得られる活物質層の柔軟性が適度となり、集電体と活物質層との密着能力が良好となる。さらに、グラファイトのような炭素材料とケイ素材料を含有する活物質同士の結合能力を高めることができるため、得られる活物質層は、柔軟性や集電体に対する密着能力がより良好なものとなる。 (4) When the content of the repeating unit (a3) is within the above range, the glass transition temperature (Tg) of the composition for an electric storage device becomes suitable. As a result, the dispersibility of the active material and the filler is improved. In addition, the flexibility of the obtained active material layer becomes moderate, and the ability to adhere the current collector to the active material layer is improved. Furthermore, since the binding ability between active materials containing a carbon material and a silicon material such as graphite can be increased, the obtained active material layer has better flexibility and adhesion ability to the current collector. .
 (メタ)アクリルアミドとしては、特に限定されないが、アクリルアミド、メタクリルアミド、N-イソプロピルアクリルアミド、N,N-ジメチルアクリルアミド、N,N-ジメチルメタクリルアミド、N,N-ジエチルアクリルアミド、N,N-ジエチルメタクリルアミド、N,N-ジメチルアミノプロピルアクリルアミド、N,N-ジメチルアミノプロピルメタクリルアミド、N-メチロールメタクリルアミド、N-メチロールアクリルアミド、ジアセトンアクリルアミド、マレイン酸アミド、アクリルアミドtert-ブチルスルホン酸等が挙げられる。これらの(メタ)アクリルアミドは、1種単独で用いてもよく、2種以上を併用してもよい。 The (meth) acrylamide is not particularly limited, but is acrylamide, methacrylamide, N-isopropylacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N-diethylmethacryl Amide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, N-methylol methacrylamide, N-methylol acrylamide, diacetone acrylamide, maleic amide, acrylamide tert-butyl sulfonic acid and the like. . These (meth) acrylamides may be used alone or in combination of two or more.
 蓄電デバイス用組成物中に含まれる全繰り返し単位の合計を100質量部としたときに、前記繰り返し単位(a2)及び前記繰り返し単位(a3)の合計量は、50質量部以上であり、55質量部以上であることが好ましく、60質量部以上であることがより好ましい。前記繰り返し単位(a2)及び前記繰り返し単位(a3)の合計量が前記範囲であると、活物質やフィラーの分散性が良好となり、柔軟性や密着性が向上するため、良好な充放電耐久特性を示す。 When the total of all the repeating units contained in the composition for an electric storage device is 100 parts by mass, the total amount of the repeating unit (a2) and the repeating unit (a3) is 50 parts by mass or more, and 55 parts by mass. Parts by weight or more, more preferably 60 parts by weight or more. When the total amount of the repeating unit (a2) and the repeating unit (a3) is within the above range, the dispersibility of the active material and the filler becomes good, and the flexibility and the adhesion are improved. Is shown.
<その他の繰り返し単位>
 上記の蓄電デバイス用組成物の製造方法の第一工程及び/又は第二工程において、前記繰り返し単位群には、前記繰り返し単位(a1)、(a2)、及び(a3)の他に、これらと共重合可能な他の単量体に由来する繰り返し単位を含有してもよい。このような繰り返し単位としては、水酸基を有する不飽和カルボン酸エステルに由来する繰り返し単位(a4)、不飽和カルボン酸エステル(ただし、前記水酸基を有する不飽和カルボン酸エステルを除く。)に由来する繰り返し単位(a5)、α,β-不飽和ニトリル化合物に由来する繰り返し単位(a6)、芳香族ビニル化合物に由来する繰り返し単位(a7)、スルホン酸基を有する化合物に由来する繰り返し単位(a8)、カチオン性単量体に由来する繰り返し単位等が挙げられる。
<Other repeating units>
In the first step and / or the second step of the method for producing a composition for an electricity storage device, the repeating unit group may include, in addition to the repeating units (a1), (a2), and (a3), It may contain a repeating unit derived from another copolymerizable monomer. Examples of such a repeating unit include a repeating unit (a4) derived from an unsaturated carboxylic acid ester having a hydroxyl group, and a repeating unit derived from an unsaturated carboxylic acid ester (excluding the unsaturated carboxylic acid ester having a hydroxyl group). A unit (a5), a repeating unit (a6) derived from an α, β-unsaturated nitrile compound, a repeating unit (a7) derived from an aromatic vinyl compound, a repeating unit (a8) derived from a compound having a sulfonic acid group, Examples include a repeating unit derived from a cationic monomer.
 水酸基を有する不飽和カルボン酸エステルの具体例としては、特に限定されないが、2-ヒドロキシエチル(メタ)アクリレート、2-ヒドロキシプロピル(メタ)アクリレート、3-ヒドロキシプロピル(メタ)アクリレート、4-ヒドロキシブチル(メタ)アクリレート、5-ヒドロキシペンチル(メタ)アクリレート、6-ヒドロキシヘキシル(メタ)アクリレート、グリセリンモノ(メタ)アクリレート、グリセリンジ(メタ)アクリレート等が挙げられる。これらの中でも、2-ヒドロキシエチル(メタ)アクリレート、グリセリンモノ(メタ)アクリレートが好ましい。なお、これらの単量体は、1種単独でまたは2種以上を組み合わせて用いることができる。 Specific examples of the unsaturated carboxylic acid ester having a hydroxyl group include, but are not particularly limited to, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl. Examples include (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, glycerin mono (meth) acrylate, and glycerin di (meth) acrylate. Among these, 2-hydroxyethyl (meth) acrylate and glycerin mono (meth) acrylate are preferred. These monomers can be used alone or in combination of two or more.
 不飽和カルボン酸エステルとしては、特に限定されないが、(メタ)アクリル酸エステルが好ましい。(メタ)アクリル酸エステルの具体例としては、(メタ)アクリル酸メチル、(メタ)アクリル酸エチル、(メタ)アクリル酸n-プロピル、(メタ)アクリル酸iso-プロピル、(メタ)アクリル酸n-ブチル、(メタ)アクリル酸i-ブチル、(メタ)アクリル酸n-アミル、(メタ)アクリル酸iso-アミル、(メタ)アクリル酸ヘキシル、(メタ)アクリル酸シクロヘキシル、(メタ)アクリル酸2-エチルヘキシル、(メタ)アクリル酸n-オクチル、(メタ)アクリル酸ノニル、(メタ)アクリル酸デシル、ジ(メタ)アクリル酸エチレングリコール、ジ(メタ)アクリル酸プロピレングリコール、トリ(メタ)アクリル酸トリメチロールプロパン、テトラ(メタ)アクリル酸ペンタエリスリトール、ヘキサ(メタ)アクリル酸ジペンタエリスリトール、(メタ)アクリル酸アリルなどを挙げることができ、これらのうちから選択される1種以上であることができる。これらのうち、(メタ)アクリル酸メチル、(メタ)アクリル酸エチル及び(メタ)アクリル酸2-エチルヘキシルから選択される1種以上であることが好ましく、(メタ)アクリル酸メチルであることが特に好ましい。 The unsaturated carboxylic acid ester is not particularly limited, but (meth) acrylic acid ester is preferable. Specific examples of the (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, and n- (meth) acrylate. -Butyl, i-butyl (meth) acrylate, n-amyl (meth) acrylate, iso-amyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acrylic acid 2 -Ethylhexyl, n-octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, tri (meth) acrylic acid Trimethylolpropane, pentaerythritol tetra (meth) acrylate, hexa (meth) acryl Acid dipentaerythritol can be mentioned (meth) allyl acrylate, can be at least one selected from among these. Among these, it is preferable to be at least one selected from methyl (meth) acrylate, ethyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, and particularly preferable is methyl (meth) acrylate. preferable.
 α,β-不飽和ニトリル化合物の具体例としては、特に限定されないが、アクリロニトリル、メタクリロニトリル、α-クロルアクリロニトリル、α-エチルアクリロニトリル、シアン化ビニリデン等を挙げることができ、これらから選択される1種以上であることができる。これらのうち、アクリロニトリル及びメタクリロニトリルから選択される1種以上であることが好ましく、アクリロニトリルであることが特に好ましい。 Specific examples of the α, β-unsaturated nitrile compound include, but are not particularly limited to, acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethylacrylonitrile, vinylidene cyanide, and the like. It can be one or more. Among these, one or more selected from acrylonitrile and methacrylonitrile are preferable, and acrylonitrile is particularly preferable.
 芳香族ビニル化合物の具体例としては、特に限定されないが、スチレン、α-メチルスチレン、p-メチルスチレン、ビニルトルエン、クロルスチレン、ジビニルベンゼン等を挙げることができ、これらのうちから選択される1種以上であることができる。これらのうち、スチレンであることが特に好ましい。 Specific examples of the aromatic vinyl compound include, but are not particularly limited to, styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, chlorostyrene, divinylbenzene, and the like. It can be more than a species. Of these, styrene is particularly preferred.
 スルホン酸基を有する化合物の具体例としては、特に限定されないが、ビニルスルホン酸、スチレンスルホン酸、アリルスルホン酸、スルホエチル(メタ)アクリレート、スルホプロピル(メタ)アクリレート、スルホブチル(メタ)アクリレート、2-アクリルアミド-2-メチルプロパンスルホン酸、2-ヒドロキシ-3-アクリルアミドプロパンスルホン酸、3-アリロキシ-2-ヒドロキシプロパンスルホン酸等のスルホン酸基を有する化合物、及びこれらのアルカリ塩などを用いてもよい。 Specific examples of the compound having a sulfonic acid group include, but are not particularly limited to, vinyl sulfonic acid, styrene sulfonic acid, allyl sulfonic acid, sulfoethyl (meth) acrylate, sulfopropyl (meth) acrylate, sulfobutyl (meth) acrylate, Compounds having a sulfonic acid group such as acrylamido-2-methylpropanesulfonic acid, 2-hydroxy-3-acrylamidopropanesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, and alkali salts thereof may be used. .
 カチオン性単量体としては、特に限定されないが、第二級アミン(塩)、第三級アミン(塩)及び第四級アンモニウム塩よりなる群から選択される少なくとも1種の単量体であることが好ましい。これらカチオン性単量体の具体例としては、特に限定されないが、(メタ)アクリル酸2-(ジメチルアミノ)エチル、ジメチルアミノエチル(メタ)アクリレート塩化メチル4級塩、(メタ)アクリル酸2-(ジエチルアミノ)エチル、(メタ)アクリル酸3-(ジメチルアミノ)プロピル、(メタ)アクリル酸3-(ジエチルアミノ)プロピル、(メタ)アクリル酸4-(ジメチルアミノ)フェニル、(メタ)アクリル酸2-[(3,5-ジメチルピラゾリル)カルボニルアミノ]エチル、(メタ)アクリル酸2-(0-[1’-メチルプロピリデンアミノ]カルボキシアミノ)エチル、(メタ)アクリル酸2-(1-アジリジニル)エチル、メタクロイルコリンクロリド、イソシアヌル酸トリス(2-アクリロイルオキシエチル)、2-ビニルピリジン、キナルジンレッド、1,2-ジ(2-ピリジル)エチレン、4’-ヒドラジノ-2-スチルバゾール二塩酸塩水和物、4-(4-ジメチルアミノスチリル)キノリン、1-ビニルイミダゾール、ジアリルアミン、ジアリルアミン塩酸塩、トリアリルアミン、ジアリルジメチルアンモニウムクロリド、ジクロルミド、N-アリルベンジルアミン、N-アリルアニリン、2,4-ジアミノ-6-ジアリルアミノ-1,3,5-トリアジン、N-trans-シンナミル-N-メチル-(1-ナフチルメチル)アミン塩酸塩、trans-N-(6,6-ジメチル-2-ヘプテン-4-イニル)-N-メチル-1-ナフチルメチルアミン塩酸塩等が挙げられる。これらの単量体は、1種単独で用いてもよく、2種以上を併用してもよい。 The cationic monomer is not particularly limited, but is at least one monomer selected from the group consisting of a secondary amine (salt), a tertiary amine (salt), and a quaternary ammonium salt. Is preferred. Specific examples of these cationic monomers include, but are not particularly limited to, 2- (dimethylamino) ethyl (meth) acrylate, quaternary salt of dimethylaminoethyl (meth) acrylate methyl chloride, 2- (meth) acrylate (Diethylamino) ethyl, 3- (dimethylamino) propyl (meth) acrylate, 3- (diethylamino) propyl (meth) acrylate, 4- (dimethylamino) phenyl (meth) acrylate, 2- (meth) acrylate [(3,5-dimethylpyrazolyl) carbonylamino] ethyl, 2- (0- [1'-methylpropylideneamino] carboxyamino) ethyl (meth) acrylate, 2- (1-aziridinyl) (meth) acrylate Ethyl, methacryloylcholine chloride, tris (2-acryloyloxyethyl) isocyanurate, 2 Vinylpyridine, quinaldine red, 1,2-di (2-pyridyl) ethylene, 4'-hydrazino-2-stilbazole dihydrochloride hydrate, 4- (4-dimethylaminostyryl) quinoline, 1-vinylimidazole, diallylamine , Diallylamine hydrochloride, triallylamine, diallyldimethylammonium chloride, dichlormide, N-allylbenzylamine, N-allylaniline, 2,4-diamino-6-diallylamino-1,3,5-triazine, N-trans-cinnamyl —N-methyl- (1-naphthylmethyl) amine hydrochloride, trans-N- (6,6-dimethyl-2-heptene-4-ynyl) -N-methyl-1-naphthylmethylamine hydrochloride, and the like. . These monomers may be used alone or in combination of two or more.
 蓄電デバイス用組成物中に含まれる全繰り返し単位の合計を100質量部としたときに、前記繰り返し単位(a5)、前記繰り返し単位(a6)及び前記繰り返し単位(a7)からなる群より選ばれる1種以上と、前記繰り返し単位(a2)との合計量は、5~50質量部以上であることが好ましい。このような繰り返し単位を前記割合で含有することにより、活物質やフィラーの分散性が良好となり、柔軟性や密着性がさらに向上するため、良好な充放電耐久特性を示す。 When the total of all the repeating units contained in the composition for an electric storage device is 100 parts by mass, 1 selected from the group consisting of the repeating unit (a5), the repeating unit (a6), and the repeating unit (a7) It is preferable that the total amount of the seeds or more and the repeating unit (a2) is 5 to 50 parts by mass or more. By containing such a repeating unit in the above-described ratio, the dispersibility of the active material and the filler is improved, and the flexibility and the adhesion are further improved.
 蓄電デバイス用組成物中に含まれる全繰り返し単位の合計を100質量部としたときに、前記繰り返し単位(a2)、前記繰り返し単位(a3)、前記繰り返し単位(a4)及び前記繰り返し単位(a8)の合計量は、50~95質量部であることが好ましく、52~92質量部であることがより好ましく、55~90質量部であることが特に好ましい。このような繰り返し単位を前記割合で含有することにより、活物質やフィラーの分散性が良好となり、柔軟性や密着性がさらに向上するため、良好な充放電耐久特性を示す。 The repeating unit (a2), the repeating unit (a3), the repeating unit (a4), and the repeating unit (a8) when the total of all the repeating units contained in the composition for an electric storage device is 100 parts by mass. Is preferably from 50 to 95 parts by mass, more preferably from 52 to 92 parts by mass, and particularly preferably from 55 to 90 parts by mass. By containing such a repeating unit in the above-described ratio, the dispersibility of the active material and the filler is improved, and the flexibility and the adhesion are further improved.
 蓄電デバイス用組成物中に含まれる全繰り返し単位の合計を100質量部としたときに、前記繰り返し単位(a1)、前記繰り返し単位(a5)、前記繰り返し単位(a6)及び前記繰り返し単位(a7)の合計量は、50質量部以下であることが好ましく、5~48質量部であることがより好ましく、8~45質量部であることが特に好ましい。このような繰り返し単位を前記割合で含有することにより、活物質やフィラーの分散性が良好となり、柔軟性や密着性がさらに向上するため、良好な充放電耐久特性を示す。 The repeating unit (a1), the repeating unit (a5), the repeating unit (a6), and the repeating unit (a7) when the total of all the repeating units contained in the composition for an electric storage device is 100 parts by mass. Is preferably 50 parts by mass or less, more preferably 5 to 48 parts by mass, and particularly preferably 8 to 45 parts by mass. By containing such a repeating unit in the above-described ratio, the dispersibility of the active material and the filler is improved, and the flexibility and the adhesion are further improved.
 1.5.蓄電デバイス用組成物の物性
 1.5.1.pH
 本実施形態に係る蓄電デバイス用組成物のpHは、6~11であることが好ましく、7~11であることがより好ましく、7~10.5であることが特に好ましい。pHが前記範囲内にあれば、レベリング性不足や液ダレ等の問題の発生を抑制することができ、良好な電気的特性と密着性とを両立させた蓄電デバイス電極を製造することが容易となる。
1.5. Physical properties of composition for power storage device 1.5.1. pH
The pH of the composition for an electricity storage device according to the present embodiment is preferably from 6 to 11, more preferably from 7 to 11, and particularly preferably from 7 to 10.5. If the pH is within the above range, it is possible to suppress the occurrence of problems such as insufficient leveling property and liquid dripping, and it is easy to manufacture an electric storage device electrode that has both good electrical characteristics and good adhesion. Become.
 本明細書における「pH」とは、以下のようにして測定される物性をいう。25℃で、pH標準液として中性リン酸塩標準液及びほう酸塩標準液で校正したガラス電極を用いたpH計で、JIS Z8802:2011に準拠して測定した値である。このようなpH計としては、例えば東亜ディーケーケー株式会社製「HM-7J」や株式会社堀場製作所製「D-51」等が挙げられる。 「" PH "in this specification refers to physical properties measured as follows. This is a value measured at 25 ° C. using a pH meter using a glass electrode calibrated with a neutral phosphate standard solution and a borate standard solution as the pH standard solution in accordance with JIS Z8802: 2011. Examples of such a pH meter include “HM-7J” manufactured by Toa DK Corporation and “D-51” manufactured by Horiba, Ltd.
 なお、蓄電デバイス用組成物のpHは、重合体粒子(A)を構成する単量体組成に影響を受けることを否定しないが、単量体組成のみで定まるものではないことを付言しておく。すなわち、一般的に同じ単量体組成であっても重合条件等で蓄電デバイス用組成物のpHが変化することが知られており、本願明細書の実施例はその一例を示しているに過ぎない。 In addition, it does not deny that the pH of the composition for an electric storage device is affected by the monomer composition constituting the polymer particles (A), but it is added that the pH is not determined only by the monomer composition. . That is, it is generally known that the pH of the composition for an electric storage device changes depending on polymerization conditions and the like even with the same monomer composition, and the examples in the specification of the present application show only one example. Absent.
 例えば、同じ単量体組成であっても、重合反応液に最初から不飽和カルボン酸を全て仕込み、その後他の単量体を順次添加して加える場合と、不飽和カルボン酸以外の単量体を重合反応液へ仕込み、最後に不飽和カルボン酸を添加する場合とでは、得られる重合体の表面に露出する不飽和カルボン酸に由来するカルボキシル基の量は異なる。このように重合方法で単量体を加える順番を変更するだけでも、蓄電デバイス用組成物のpHは大きく異なると考えられる。 For example, even if the monomer composition is the same, the polymerization reaction solution is charged with all of the unsaturated carboxylic acid from the beginning, and then the other monomers are sequentially added and added, and the monomer other than the unsaturated carboxylic acid is added. Is added to the polymerization reaction solution, and the amount of carboxyl groups derived from the unsaturated carboxylic acid exposed on the surface of the obtained polymer is different from the case where the unsaturated carboxylic acid is finally added. It is considered that the pH of the composition for an electric storage device is greatly different only by changing the order of adding the monomers by the polymerization method.
 1.5.2.粘度
 重合体粒子(A)の5質量%水分散液のpH9における粘度は、500~150,000mPa・sであることが好ましく、1,000~150,000mPa・sであることがより好ましく、2,000~150,000mPa・sであることが特に好ましい。pH9における粘度が前記下限値以上であると、活物質やフィラーの分散性が良好となり、均質なスラリーを作成できるため好ましい。pH9における粘度が前記上限値以下であると、重合体粒子(A)自体の分散性が良好となるため好ましい。
1.5.2. Viscosity The viscosity of the 5% by mass aqueous dispersion of the polymer particles (A) at pH 9 is preferably from 500 to 150,000 mPa · s, more preferably from 1,000 to 150,000 mPa · s, and It is particularly preferred that the viscosity is in the range of 2,000 to 150,000 mPa · s. It is preferable that the viscosity at pH 9 is equal to or higher than the lower limit, because the dispersibility of the active material and the filler becomes good and a uniform slurry can be prepared. It is preferable that the viscosity at pH 9 is equal to or less than the above upper limit because the dispersibility of the polymer particles (A) itself becomes good.
 なお、重合体粒子(A)の5質量%水分散液の粘度は、温度25.0℃において、B型粘度計を用いて、JIS Z 8803に準拠して測定した値である。B型粘度計としては、例えば東機産業社製「RB-80L」や「TVB-10」等を使用することができる。 粘度 The viscosity of the 5% by mass aqueous dispersion of the polymer particles (A) is a value measured at a temperature of 25.0 ° C. using a B-type viscometer in accordance with JIS Z 8803. As the B-type viscometer, for example, "RB-80L" or "TVB-10" manufactured by Toki Sangyo Co., Ltd. can be used.
 1.5.3.数平均粒子径
 本実施形態に係る蓄電デバイス用組成物の数平均粒子径は、50~500nmであることが好ましく、60~450nmであることがより好ましく、70~400nmであることが特に好ましい。蓄電デバイス用組成物の数平均粒子径が前記範囲にあると、活物質の表面に蓄電デバイス用組成物が吸着しやすくなるので、活物質の移動に伴って蓄電デバイス用組成物も追従して移動することができる。その結果、両者の粒子のうちのいずれかのみが単独でマイグレーションすることを抑制できるので、電気的特性の劣化を低減することができる。
1.5.3. Number Average Particle Size The number average particle size of the composition for an electricity storage device according to the present embodiment is preferably 50 to 500 nm, more preferably 60 to 450 nm, and particularly preferably 70 to 400 nm. When the number average particle diameter of the composition for a power storage device is in the above range, the composition for a power storage device is easily adsorbed on the surface of the active material, so that the composition for a power storage device also moves following the movement of the active material. be able to. As a result, only one of the particles can be prevented from migrating alone, so that the deterioration of the electrical characteristics can be reduced.
 なお、蓄電デバイス用組成物の数平均粒子径は、透過型電子顕微鏡(TEM)により観察した蓄電デバイス用組成物の画像より得られる粒子径50個の平均値より算出することができる。透過型電子顕微鏡としては、例えば株式会社日立ハイテクノロジーズ製の「H-7650」などが挙げられる。 The number average particle diameter of the composition for a power storage device can be calculated from the average value of 50 particle diameters obtained from an image of the composition for a power storage device observed by a transmission electron microscope (TEM). Examples of the transmission electron microscope include “H-7650” manufactured by Hitachi High-Technologies Corporation.
 1.5.4.ガラス転移温度
 本実施形態に係る蓄電デバイス用組成物は、JIS K7121に準拠する示差走査熱量測定(DSC)によって測定したときに、60℃~160℃の温度範囲において吸熱ピークを1つのみ有するものであることが好ましい。この吸熱ピークの温度(すなわちガラス転移温度(Tg))は、70℃~150℃の範囲にあることがより好ましい。DSC分析における蓄電デバイス用組成物の吸熱ピークが1つのみであり、かつ、該ピーク温度が前記範囲にある場合、蓄電デバイス用組成物は良好な密着性を示すとともに、活物質層に対してより良好な柔軟性及び粘着性を付与することができ好ましい。
1.5.4. Glass transition temperature The composition for an electricity storage device according to the present embodiment has only one endothermic peak in a temperature range of 60 ° C. to 160 ° C. when measured by differential scanning calorimetry (DSC) according to JIS K7121. It is preferable that The temperature of the endothermic peak (ie, the glass transition temperature (Tg)) is more preferably in the range of 70 ° C. to 150 ° C. When the composition for an electricity storage device has only one endothermic peak in the DSC analysis, and the peak temperature is in the above range, the composition for an electricity storage device shows good adhesion and also has a good adhesion to the active material layer. It is preferable because better flexibility and tackiness can be imparted.
 2.蓄電デバイス用スラリー
 本実施形態に係る蓄電デバイス用スラリーは、上述の蓄電デバイス用組成物を含有するものである。本実施形態に係る蓄電デバイス用組成物は、上述したように、充放電に伴って発生するデンドライトに起因する短絡を抑制するための保護膜を形成するための材料として使用することもできるし、活物質同士の結合能力及び活物質と集電体との密着能力並びに粉落ち耐性を向上させた蓄電デバイス電極(活物質層)を作製するための材料として使用することもできる。そのため、保護膜を形成するための蓄電デバイス用スラリー(以下、「保護膜形成用スラリー」ともいう。)と、蓄電デバイス電極の活物質層を形成するための蓄電デバイス用スラリー(以下、「蓄電デバイス電極用スラリー」ともいう。)とに分けて説明する。
2. Slurry for an electricity storage device The slurry for an electricity storage device according to the present embodiment contains the composition for an electricity storage device described above. As described above, the composition for an electricity storage device according to the present embodiment can also be used as a material for forming a protective film for suppressing a short circuit caused by dendrite generated due to charge and discharge, It can also be used as a material for producing an electricity storage device electrode (active material layer) having improved binding ability between active materials, adhesion between the active material and the current collector, and powder drop resistance. Therefore, a slurry for an electricity storage device for forming a protective film (hereinafter, also referred to as a “slurry for forming a protection film”) and a slurry for an electricity storage device for forming an active material layer of an electrode for an electricity storage device (hereinafter, referred to as “storing electricity”) Also referred to as "device electrode slurry").
 2.1.保護膜形成用スラリー
 本明細書における「保護膜形成用スラリー」とは、これを電極またはセパレータの表面もしくはその両方に塗布した後、乾燥させて、電極またはセパレータの表面もしくはその両方に保護膜を形成するために用いられる分散液のことをいう。本実施形態に係る保護膜形成用スラリーは、上述した蓄電デバイス用組成物のみから構成されていてもよく、無機フィラーをさらに含有してもよい。以下、本実施形態に係る保護膜形成用スラリーに含まれる各成分について詳細に説明する。なお、蓄電デバイス用組成物については、上述した通りであるので説明を省略する。
2.1. Slurry for forming protective film In the present specification, "slurry for forming a protective film" refers to coating the slurry on the surface of the electrode or the separator or both and then drying it to form a protective film on the surface of the electrode or the separator or both. Refers to a dispersion used for forming. The slurry for forming a protective film according to the present embodiment may be composed only of the above-described composition for a power storage device, or may further contain an inorganic filler. Hereinafter, each component contained in the protective film forming slurry according to the present embodiment will be described in detail. Note that the composition for a power storage device is as described above, and a description thereof will be omitted.
 2.1.1.無機フィラー
 本実施形態に係る保護膜形成用スラリーは、無機フィラーを含有することにより、形成される保護膜のタフネスを向上させることができる。無機フィラーとしては、シリカ、酸化チタン(チタニア)、酸化アルミニウム(アルミナ)、酸化ジルコニウム(ジルコニア)、及び酸化マグネシウム(マグネシア)よりなる群から選択される少なくとも1種の粒子を用いることが好ましい。これらの中でも、保護膜のタフネスをより向上させる観点から、酸化チタン、酸化アルミニウムが好ましい。また、酸化チタンとしてはルチル型の酸化チタンがより好ましい。
2.1.1. Inorganic filler The protective film forming slurry according to the present embodiment can improve the toughness of the formed protective film by containing the inorganic filler. As the inorganic filler, it is preferable to use at least one kind of particles selected from the group consisting of silica, titanium oxide (titania), aluminum oxide (alumina), zirconium oxide (zirconia), and magnesium oxide (magnesia). Among them, titanium oxide and aluminum oxide are preferable from the viewpoint of further improving the toughness of the protective film. Further, as the titanium oxide, rutile-type titanium oxide is more preferable.
 無機フィラーの平均粒子径は、1μm以下であることが好ましく、0.1~0.8μmの範囲内であることがより好ましい。なお、無機フィラーの平均粒子径は、多孔質膜であるセパレータの平均孔径よりも大きいことが好ましい。これにより、セパレータへのダメージを軽減し、無機フィラーがセパレータの微多孔に詰まることを防ぐことができる。 平均 The average particle size of the inorganic filler is preferably 1 μm or less, more preferably in the range of 0.1 to 0.8 μm. The average particle size of the inorganic filler is preferably larger than the average pore size of the separator that is a porous membrane. Thereby, damage to the separator can be reduced, and it is possible to prevent the inorganic filler from clogging the micropores of the separator.
 本実施形態に係る保護膜形成用スラリーは、無機フィラー100質量部に対して、上述の蓄電デバイス用組成物が、固形分換算で0.1~20質量部含有されていることが好ましく、1~10質量部含有されていることがより好ましい。蓄電デバイス用組成物の含有割合が前記範囲であることにより、形成される保護膜のタフネスとリチウムイオンの透過性とのバランスが良好となり、その結果、得られる蓄電デバイスの抵抗上昇率をより低くすることができる。 The slurry for forming a protective film according to the present embodiment preferably contains 0.1 to 20 parts by mass of the above-mentioned composition for an electric storage device in terms of solid content based on 100 parts by mass of the inorganic filler. More preferably, it is contained in an amount of up to 10 parts by mass. When the content ratio of the composition for a power storage device is in the above range, the balance between the toughness of the formed protective film and the permeability of lithium ions is improved, and as a result, the resistance increase rate of the obtained power storage device is lower. can do.
 2.1.2.液状媒体
 本実施形態に係る保護膜形成用スラリーは、上述の蓄電デバイス用組成物の「1.2.液状媒体(B)」に記載されている材料を必要に応じて用いることができる。液状媒体の添加量は、塗工方法等に応じて最適なスラリーの粘度が得られるように、必要に応じて調整することができる。
2.1.2. Liquid Medium The material described in “1.2. Liquid Medium (B)” of the above-described composition for an electric storage device can be used as needed in the slurry for forming a protective film according to the present embodiment. The amount of the liquid medium to be added can be adjusted as necessary so as to obtain the optimum viscosity of the slurry according to the coating method or the like.
 2.1.3.その他の成分
 本実施形態に係る保護膜形成用スラリーは、上述の蓄電デバイス用組成物の「1.3.その他の添加剤」に記載されている材料を必要に応じて適量用いることができる。
2.1.3. Other Components In the slurry for forming a protective film according to the present embodiment, an appropriate amount of the material described in “1.3. Other additives” of the composition for an electric storage device described above can be used as needed.
 2.2.蓄電デバイス電極用スラリー
 本明細書における「蓄電デバイス電極用スラリー」とは、これを集電体の表面に塗布した後、乾燥させて、集電体表面上に活物質層を形成するために用いられる分散液のことをいう。本実施形態に係る蓄電デバイス電極用スラリーは、上述の蓄電デバイス用組成物と、活物質とを含有する。
2.2. Slurry for power storage device electrode The “slurry for power storage device electrode” in this specification is used to form an active material layer on the surface of the current collector by applying it to the surface of the current collector and then drying it. Refers to the resulting dispersion. The slurry for an electricity storage device electrode according to the present embodiment contains the above-described composition for an electricity storage device and an active material.
 一般的に、蓄電デバイス電極用スラリーは、密着性を向上させるために、SBR系共重合体などのバインダー成分と、カルボキシメチルセルロース等の増粘剤とを含有することが多い。一方、本実施形態に係る蓄電デバイス電極用スラリーは、上述した重合体粒子(A)のみでも柔軟性及び密着性を向上させることができる。もちろん、本実施形態に係る蓄電デバイス電極用スラリーは、さらに密着性を向上させるために、重合体粒子(A)以外の重合体や増粘剤を含有してもよい。 Generally, the slurry for an electricity storage device electrode often contains a binder component such as an SBR-based copolymer and a thickener such as carboxymethyl cellulose in order to improve adhesion. On the other hand, the slurry for an electricity storage device electrode according to the present embodiment can improve flexibility and adhesion even with only the polymer particles (A) described above. Of course, the slurry for an electricity storage device electrode according to the present embodiment may contain a polymer other than the polymer particles (A) and a thickener in order to further improve the adhesion.
 以下、本実施形態に係る蓄電デバイス電極用スラリーに含まれる成分について説明する。 成分 Hereinafter, components contained in the slurry for an electricity storage device electrode according to the present embodiment will be described.
 2.2.1.重合体粒子(A)
 重合体粒子(A)の組成、特性、製造方法については、上述した通りであるので、説明を省略する。
2.2.1. Polymer particles (A)
The composition, characteristics, and production method of the polymer particles (A) are as described above, and thus description thereof is omitted.
 本実施形態に係る蓄電デバイス電極用スラリー中の重合体粒子(A)の含有割合は、活物質100質量部に対し、1~8質量部であることが好ましく、1~7質量部であることがより好ましく、1.5~6質量部であることが特に好ましい。重合体粒子(A)の含有割合が前記範囲にあると、スラリー中の活物質の分散性が良好となり、スラリーの塗布性も優れたものとなる。本実施形態に係る蓄電デバイス電極用スラリーが、重合体粒子(A)以外の重合体や増粘剤を含有する場合も同様である。 The content ratio of the polymer particles (A) in the slurry for an electric storage device electrode according to the present embodiment is preferably 1 to 8 parts by mass, and more preferably 1 to 7 parts by mass with respect to 100 parts by mass of the active material. Is more preferably 1.5 to 6 parts by mass. When the content ratio of the polymer particles (A) is in the above range, the dispersibility of the active material in the slurry becomes good, and the applicability of the slurry becomes excellent. The same applies to the case where the slurry for an electricity storage device electrode according to the present embodiment contains a polymer other than the polymer particles (A) and a thickener.
 2.2.2.活物質
 本実施形態に係る蓄電デバイス電極用スラリーに使用される活物質としては、例えば炭素材料、ケイ素材料、リチウム原子を含む酸化物、鉛化合物、錫化合物、砒素化合物、アンチモン化合物、アルミニウム化合物などが挙げられる。これらの具体例としては、特許第5999399号公報等に記載された化合物が挙げられる。
2.2.2. Active Material Examples of the active material used in the slurry for an electricity storage device electrode according to the present embodiment include a carbon material, a silicon material, an oxide containing a lithium atom, a lead compound, a tin compound, an arsenic compound, an antimony compound, and an aluminum compound. Is mentioned. Specific examples of these include compounds described in Japanese Patent No. 5999399.
 また、活物質層中には、以下に例示する活物質を含んでもよい。例えばポリアセン等の導電性高分子;A(但し、Aはアルカリ金属または遷移金属、Bはコバルト、ニッケル、アルミニウム、スズ、マンガン等の遷移金属から選択される少なくとも1種、Oは酸素原子を表し、X、Y及びZはそれぞれ1.10>X>0.05、4.00>Y>0.85、5.00>Z>1.5の範囲の数である。)で表される複合金属酸化物や、その他の金属酸化物等が挙げられる。 Further, the active material layer may contain an active material exemplified below. For example, a conductive polymer such as polyacene; A X B Y O Z (where A is an alkali metal or a transition metal, B is at least one selected from transition metals such as cobalt, nickel, aluminum, tin, and manganese; Represents an oxygen atom, and X, Y and Z are numbers in the range of 1.10>X> 0.05, 4.00>Y> 0.85, 5.00>Z> 1.5.) And other metal oxides and the like.
 本実施形態に係る蓄電デバイス電極用スラリーは、正極及び負極のいずれの蓄電デバイス電極を作製する際にも使用することができ、正極及び負極の両方に使用することが好ましい。 (4) The slurry for an electricity storage device electrode according to the present embodiment can be used when producing any of the electricity storage device electrodes of the positive electrode and the negative electrode, and is preferably used for both the positive electrode and the negative electrode.
 正極活物質としてリン酸鉄リチウムを使用する場合、充放電特性が十分ではなく密着性が劣るという課題があった。リン酸鉄リチウムは、微細な一次粒径を有し、その二次凝集体であることが知られており、充放電を繰り返す際に活物質層中で凝集が崩壊し活物質同士の乖離を引き起こし、集電体からの剥離や、活物質層内部の導電ネットワークが寸断されやすいことが要因の一つであると考えられる。 (4) When lithium iron phosphate is used as the positive electrode active material, there is a problem that the charge / discharge characteristics are not sufficient and the adhesion is poor. Lithium iron phosphate has a fine primary particle size, and is known to be a secondary aggregate thereof.When charge and discharge are repeated, aggregation collapses in the active material layer and dissociation between the active materials occurs. This is considered to be one of the factors that peel off from the current collector and that the conductive network inside the active material layer is easily broken.
 しかしながら、本実施形態に係る蓄電デバイス電極用スラリーを用いて作製された蓄電デバイス電極では、リン酸鉄リチウムを使用した場合でも上述のような問題が発生することなく、良好な電気的特性を示すことができる。この理由としては、重合体粒子(A)がリン酸鉄リチウムを強固に結着させることができると同時に、充放電中においてもリン酸鉄リチウムを強固に結着させた状態を維持することができるからであると考えられる。 However, the power storage device electrode manufactured using the slurry for a power storage device electrode according to the present embodiment does not have the above-described problem even when lithium iron phosphate is used, and exhibits good electrical characteristics. be able to. The reason for this is that the polymer particles (A) can bind lithium iron phosphate firmly, and at the same time, maintain the state in which lithium iron phosphate is firmly bound even during charge and discharge. It is thought that it is possible.
 一方、負極を作製する場合には、上記例示した活物質の中でもケイ素材料を含有するものであることが好ましい。ケイ素材料は単位重量当たりのリチウムの吸蔵量がその他の活物質と比較して大きいことから、負極活物質としてのケイ素材料を含有することにより、得られる蓄電デバイスの蓄電容量を高めることができ、その結果、蓄電デバイスの出力及びエネルギー密度を高くすることができる。 On the other hand, when producing a negative electrode, it is preferable that the active material contains a silicon material among the active materials exemplified above. Since the silicon material has a large lithium storage capacity per unit weight as compared with other active materials, by containing the silicon material as the negative electrode active material, the storage capacity of the obtained power storage device can be increased, As a result, the output and energy density of the power storage device can be increased.
 また、負極活物質としては、ケイ素材料と炭素材料との混合物であることがより好ましい。炭素材料は充放電に伴う体積変化が小さいから、負極活物質としてケイ素材料と炭素材料との混合物を使用することにより、ケイ素材料の体積変化の影響を緩和することができ、活物質層と集電体との密着能力をより向上させることができる。 More preferably, the negative electrode active material is a mixture of a silicon material and a carbon material. Since the change in volume of a carbon material due to charge and discharge is small, by using a mixture of a silicon material and a carbon material as a negative electrode active material, the effect of the volume change of the silicon material can be reduced, and the active material layer and the active material layer can be collected. The ability to adhere to the electric body can be further improved.
 シリコン(Si)を活物質として使用する場合、シリコンは、高容量である一方、リチウムを吸蔵する際に大きな体積変化を生じる。このため、ケイ素材料は膨張と収縮の繰り返しによって微粉化、集電体からの剥離や、活物質同士の乖離を引き起こし、活物質層内部の導電ネットワークが寸断されやすいという性質がある。これにより、短時間でサイクル特性が極端に劣化してしまうのである。 When silicon (Si) is used as an active material, while silicon has a high capacity, a large volume change occurs when occluding lithium. For this reason, the silicon material has the property that it is pulverized, peeled from the current collector, or separated from the active materials due to repeated expansion and contraction, and the conductive network inside the active material layer is easily broken. As a result, the cycle characteristics are extremely deteriorated in a short time.
 しかしながら、本実施形態に係る蓄電デバイス電極用スラリーを用いて作製された蓄電デバイス電極では、ケイ素材料を使用した場合でも上述のような問題が発生することなく、良好な電気的特性を示すことができる。この理由としては、重合体粒子(A)がケイ素材料を強固に結着させることができると同時に、リチウムを吸蔵することによりケイ素材料が体積膨張しても重合体粒子(A)が伸び縮みしてケイ素材料を強固に結着させた状態を維持することができるからであると考えられる。 However, in the electricity storage device electrode manufactured using the electricity storage device electrode slurry according to the present embodiment, even when a silicon material is used, the above-described problem does not occur, and good electrical characteristics can be exhibited. it can. This is because the polymer particles (A) can firmly bind the silicon material, and the polymer particles (A) expand and contract even if the silicon material expands in volume by absorbing lithium. It is considered that the state in which the silicon material is firmly bound can be maintained.
 活物質100質量%中に占めるケイ素材料の含有割合は、1質量%以上とすることが好ましく、1~50質量%とすることがより好ましく、5~45質量%とすることがさらに好ましく、10~40質量%とすることが特に好ましい。活物質100質量%中に占めるケイ素材料の含有割合が前記範囲内であると、蓄電デバイスの出力及びエネルギー密度の向上と充放電耐久特性とのバランスに優れた蓄電デバイスが得られる。 The content ratio of the silicon material in 100% by mass of the active material is preferably 1% by mass or more, more preferably 1 to 50% by mass, still more preferably 5 to 45% by mass. It is particularly preferred that the content be set to 4040% by mass. When the content ratio of the silicon material in 100% by mass of the active material is within the above range, a power storage device having an excellent balance between improvement in output and energy density of the power storage device and charge / discharge durability characteristics can be obtained.
 活物質の形状としては、粒状であることが好ましい。活物質の平均粒子径としては、0.1~100μmであることが好ましく、1~20μmであることがより好ましい。ここで、活物質の平均粒子径とは、レーザー回折法を測定原理とする粒度分布測定装置を用いて粒度分布を測定し、その粒度分布から算出される体積平均粒子径である。このようなレーザー回折式粒度分布測定装置としては、例えばHORIBA LA-300シリーズ、HORIBA LA-920シリーズ(以上、株式会社堀場製作所製)などを挙げることができる。 The active material preferably has a granular shape. The average particle size of the active material is preferably from 0.1 to 100 μm, more preferably from 1 to 20 μm. Here, the average particle size of the active material is a volume average particle size calculated from the particle size distribution measured by a particle size distribution measuring device using a laser diffraction method as a measurement principle. Examples of such a laser diffraction type particle size distribution measuring apparatus include HORIBA @ LA-300 series and HORIBA @ LA-920 series (all manufactured by Horiba, Ltd.).
 2.2.3.その他の成分
 本実施形態に係る蓄電デバイス電極用スラリーには、上述した成分以外に、必要に応じてその他の成分を添加してもよい。このような成分としては、例えば重合体粒子(A)以外の重合体、増粘剤、導電付与剤、液状媒体(ただし、蓄電デバイス用組成物からの持ち込み分を除く。)、pH調整剤、腐食防止剤などが挙げられる。重合体粒子(A)以外の重合体及び増粘剤としては、上述の「1.3.その他の添加剤」で例示した化合物の中から選択して、同様の目的及び含有割合で用いることができる。導電付与剤としては、特許第5999399号公報等に記載された化合物が挙げられる。
2.2.3. Other Components In addition to the above-described components, other components may be added to the slurry for an electricity storage device electrode according to the present embodiment, if necessary. Such components include, for example, polymers other than the polymer particles (A), thickeners, conductivity-imparting agents, liquid media (excluding carry-on components from the composition for power storage devices), pH adjusters, Corrosion inhibitors and the like. The polymer other than the polymer particles (A) and the thickener may be selected from the compounds exemplified in the above “1.3. Other additives” and used for the same purpose and content. it can. Examples of the conductivity imparting agent include compounds described in Japanese Patent No. 5999399 and the like.
<液状媒体>
 本実施形態に係る蓄電デバイス電極用スラリーに追加で添加し得る液状媒体は、蓄電デバイス用組成物に含まれていた液状媒体(B)と同種であってもよく、異なっていてもよいが、上述の「1.2.液状媒体(B)」で例示した液状媒体の中から選択して使用されることが好ましい。
<Liquid medium>
The liquid medium that can be additionally added to the slurry for an electricity storage device electrode according to the present embodiment may be the same as or different from the liquid medium (B) contained in the composition for an electricity storage device, It is preferable to use by selecting from the liquid media exemplified in “1.2. Liquid Medium (B)” above.
 本実施形態に係る蓄電デバイス電極用スラリーにおける液状媒体(蓄電デバイス用組成物からの持ち込み分を含む。)の使用割合は、スラリー中の固形分濃度(スラリー中の液状媒体以外の成分の合計質量がスラリーの全質量に占める割合をいう。以下同じ。)が、30~70質量%となる割合とすることが好ましく、40~60質量%となる割合とすることがより好ましい。 The usage ratio of the liquid medium (including the amount brought in from the power storage device composition) in the slurry for the power storage device electrode according to the present embodiment is determined by the solid content concentration in the slurry (total mass of components other than the liquid medium in the slurry). Is the ratio to the total mass of the slurry. The same applies hereinafter.) Is preferably 30 to 70% by mass, more preferably 40 to 60% by mass.
<pH調整剤・腐食防止剤>
 本実施形態に係る蓄電デバイス電極用スラリーは、活物質の種類に応じて集電体の腐食を抑制することを目的として、pH調整剤または腐食防止剤を含有することができる。
<PH adjuster / corrosion inhibitor>
The slurry for a power storage device electrode according to the present embodiment can contain a pH adjuster or a corrosion inhibitor for the purpose of suppressing corrosion of the current collector according to the type of the active material.
 pH調整剤としては、例えば、塩酸、リン酸、硫酸、酢酸、ギ酸、リン酸アンモニウム、硫酸アンモニウム、酢酸アンモニウム、ギ酸アンモニウム、塩化アンモニウム、水酸化ナトリウム、水酸化カリウムなどを挙げることでき、これらの中でも硫酸、硫酸アンモニウム、水酸化ナトリウム、水酸化カリウムが好ましい。また、重合体粒子(A)の製造方法中に記載された化合物の中から選択して使用することもできる。 Examples of the pH adjusting agent include, for example, hydrochloric acid, phosphoric acid, sulfuric acid, acetic acid, formic acid, ammonium phosphate, ammonium sulfate, ammonium acetate, ammonium formate, ammonium chloride, sodium hydroxide, potassium hydroxide and the like. Sulfuric acid, ammonium sulfate, sodium hydroxide and potassium hydroxide are preferred. Further, it can be used by selecting from the compounds described in the method for producing the polymer particles (A).
 腐食防止剤としては、メタバナジン酸アンモニウム、メタバナジン酸ナトリウム、メタバナジン酸カリウム、メタタングステン酸アンモニウム、メタタングステン酸ナトリウム、メタタングステン酸カリウム、パラタングステン酸アンモニウム、パラタングステン酸ナトリウム、パラタングステン酸カリウム、モリブデン酸アンモニウム、モリブデン酸ナトリウム、モリブデン酸カリウムなどが挙げられ、これらの中でもパラタングステン酸アンモニウム、メタバナジン酸アンモニウム、メタバナジン酸ナトリウム、メタバナジン酸カリウム、モリブデン酸アンモニウムが好ましい。 As the corrosion inhibitor, ammonium metavanadate, sodium metavanadate, potassium metavanadate, ammonium metatungstate, sodium metatungstate, potassium metatungstate, ammonium paratungstate, sodium paratungstate, potassium paratungstate, molybdate Examples thereof include ammonium, sodium molybdate, and potassium molybdate. Among these, ammonium paratungstate, ammonium metavanadate, sodium metavanadate, potassium metavanadate, and ammonium molybdate are preferable.
 2.2.4.蓄電デバイス電極用スラリーの調製方法
 本実施形態に係る蓄電デバイス電極用スラリーは、上述の蓄電デバイス用組成物と活物質とを含有するものである限り、どのような方法によって製造されたものであってもよいが、例えば特許第5999399号公報等に記載されている方法により製造することができる。
2.2.4. Method for preparing slurry for power storage device electrode The slurry for power storage device electrode according to the present embodiment is manufactured by any method as long as it contains the above-described composition for power storage device and an active material. Alternatively, it can be manufactured by a method described in, for example, Japanese Patent No. 5999399.
 3.蓄電デバイス電極
 本実施形態に係る蓄電デバイス電極は、集電体と、前記集電体の表面上に上述の蓄電デバイス電極用スラリーが塗布及び乾燥されて形成された活物質層と、を備えるものである。かかる蓄電デバイス電極は、金属箔などの集電体の表面に、上述の蓄電デバイス電極用スラリーを塗布して塗膜を形成し、次いで該塗膜を乾燥して活物質層を形成することにより製造することができる。このようにして製造された蓄電デバイス電極は、集電体上に、上述の重合体粒子(A)及び活物質、さらに必要に応じて添加した任意成分を含有する活物質層が結着されてなるものであるから、柔軟性及び密着性に優れるとともに、良好な充放電耐久特性を示す。
3. Power storage device electrode The power storage device electrode according to the present embodiment includes a current collector, and an active material layer formed by applying and drying the above-described slurry for a power storage device electrode on the surface of the current collector. It is. Such a power storage device electrode is formed by applying the above-mentioned slurry for a power storage device electrode to a surface of a current collector such as a metal foil to form a coating film, and then drying the coating film to form an active material layer. Can be manufactured. The thus-produced power storage device electrode is obtained by binding the above-mentioned polymer particles (A), an active material, and an active material layer containing an optional component added as necessary to a current collector. Therefore, it is excellent in flexibility and adhesion, and shows good charge / discharge durability characteristics.
 集電体としては、導電性材料からなるものであれば特に制限されないが、例えば特許第5999399号公報等の記載されている集電体が挙げられる。 The current collector is not particularly limited as long as it is made of a conductive material, and examples thereof include a current collector described in Japanese Patent No. 5999399.
 蓄電デバイス電極用スラリーの集電体への塗布方法についても特に制限はなく、例えば特許第5999399号公報等の記載されている方法により塗布することができる。このようにして製造された蓄電デバイス電極は、柔軟性及び密着性に優れるとともに、良好な充放電耐久特性を示す。 There is no particular limitation on the method of applying the slurry for an electrode for a power storage device to a current collector, and the slurry can be applied by a method described in, for example, Japanese Patent No. 5999399. The electricity storage device electrode manufactured in this way has excellent flexibility and adhesion, and exhibits good charge / discharge durability.
 本実施形態に係る蓄電デバイス電極において、活物質としてケイ素材料を用いる場合、活物質層100質量部中のシリコン元素の含有割合が2~30質量部であることが好ましく、2~20質量部であることがより好ましく、3~10質量部であることが特に好ましい。活物質層中のシリコン元素の含有量が前記範囲内であると、それを用いて作製される蓄電デバイスの蓄電容量が向上することに加え、シリコン元素の分布が均一な活物質層が得られる。 When a silicon material is used as the active material in the electricity storage device electrode according to the present embodiment, the content ratio of the silicon element in 100 parts by mass of the active material layer is preferably 2 to 30 parts by mass, and preferably 2 to 20 parts by mass. More preferably, it is particularly preferably 3 to 10 parts by mass. When the content of the silicon element in the active material layer is within the above range, the power storage capacity of a power storage device manufactured using the same is improved, and an active material layer with a uniform distribution of the silicon element is obtained. .
 本発明において活物質層中のシリコン元素の含有量は、例えば、特許第5999399号公報等に記載された方法により測定することができる。 に お い て In the present invention, the content of the silicon element in the active material layer can be measured, for example, by a method described in Japanese Patent No. 5999399.
 4.蓄電デバイス
 本実施形態に係る蓄電デバイスは、上述の蓄電デバイス電極を備え、さらに電解液を含有し、セパレータなどの部品を用いて、常法に従って製造することができる。具体的な製造方法としては、例えば、負極と正極とをセパレータを介して重ね合わせ、これを電池形状に応じて巻く、折るなどして電池容器に収納し、該電池容器に電解液を注入して封口する方法などを挙げることができる。電池の形状は、コイン型、円筒型、角形、ラミネート型など、適宜の形状であることができる。
4. Power Storage Device The power storage device according to the present embodiment includes the above-described power storage device electrode, further contains an electrolytic solution, and can be manufactured using a component such as a separator according to a conventional method. As a specific manufacturing method, for example, a negative electrode and a positive electrode are overlapped with a separator interposed therebetween, and this is wound in accordance with the shape of the battery, folded, stored in a battery container, and an electrolytic solution is injected into the battery container. And sealing. The shape of the battery can be an appropriate shape such as a coin type, a cylindrical type, a square type, a laminate type, and the like.
 電解液は、液状でもゲル状でもよく、活物質の種類に応じて、蓄電デバイスに用いられる公知の電解液の中から電池としての機能を効果的に発現するものを選択すればよい。電解液は、電解質を適当な溶媒に溶解した溶液であることができる。これら電解質や溶媒については、例えば、特許第5999399号公報等に記載された化合物が挙げられる。 (4) The electrolyte may be liquid or gel, and may be selected from known electrolytes used for power storage devices that effectively exhibit the function as a battery, depending on the type of active material. The electrolytic solution can be a solution in which the electrolyte is dissolved in a suitable solvent. As these electrolytes and solvents, for example, compounds described in Japanese Patent No. 5999399 are exemplified.
 5.実施例
 以下、本発明を実施例に基づいて具体的に説明するが、本発明はこれらの実施例に限定されるものではない。実施例、比較例中の「部」及び「%」は、特に断らない限り質量基準である。
5. EXAMPLES Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. “Parts” and “%” in Examples and Comparative Examples are based on mass unless otherwise specified.
 5.1.実施例1
 5.1.1.蓄電デバイス用組成物の調製及び評価
(1)蓄電デバイス用組成物の調製
 以下に示すような二段重合により、重合体粒子(A1)を含有する蓄電デバイス用組成物を得た。まず、一段目の重合では、反応器に、水220質量部と、1,3-ブタジエン8質量部、スチレン12質量部、アクリル酸2質量部からなる単量体混合物22質量部と、連鎖移動剤としてt-ドデシルメルカプタン0.1質量部と、乳化剤としてアルキルジフェニルエーテルジスルホン酸ナトリウム1質量部と、重合開始剤として過硫酸カリウム0.2質量部とを仕込み、攪拌しながら60℃で18時間重合し、重合添加率96%で反応を終了した。続いて、二段目の重合では、この反応器に、水180質量部と、アクリル酸18質量部と、アクリルアミド60質量部と、重合開始剤として過硫酸カリウム0.2質量部とを添加して80℃にて2時間重合反応を継続した後、反応を終了させた。このときの重合添加率は98%であった。このようにして得られた重合体粒子(A1)の分散液から未反応単量体を除去し、濃縮後10%水酸化ナトリウム水溶液及び水を添加して、重合体粒子(A1)を20質量%含有するpH9.0の蓄電デバイス用組成物を得た。
5.1. Example 1
5.1.1. Preparation and evaluation of composition for power storage device (1) Preparation of composition for power storage device A power storage device composition containing polymer particles (A1) was obtained by two-stage polymerization as described below. First, in the first-stage polymerization, 220 parts by mass of water, 22 parts by mass of a monomer mixture composed of 8 parts by mass of 1,3-butadiene, 12 parts by mass of styrene, and 2 parts by mass of acrylic acid were put into a reactor, followed by chain transfer. 0.1 parts by mass of t-dodecyl mercaptan as an agent, 1 part by mass of sodium alkyldiphenyl ether disulfonate as an emulsifier, and 0.2 parts by mass of potassium persulfate as a polymerization initiator, and polymerized at 60 ° C. for 18 hours while stirring. Then, the reaction was terminated at a polymerization addition rate of 96%. Subsequently, in the second-stage polymerization, 180 parts by mass of water, 18 parts by mass of acrylic acid, 60 parts by mass of acrylamide, and 0.2 parts by mass of potassium persulfate as a polymerization initiator were added to the reactor. After the polymerization reaction was continued at 80 ° C. for 2 hours, the reaction was terminated. At this time, the polymerization addition rate was 98%. The unreacted monomer was removed from the dispersion liquid of the polymer particles (A1) thus obtained, and after concentration, a 10% aqueous sodium hydroxide solution and water were added to the polymer particles (A1) in an amount of 20% by mass. % Of a composition for an electricity storage device having a pH of 9.0.
(2)数平均粒子径の測定
 上記で得られた蓄電デバイス用組成物を0.1wt%に希釈したラテックスをコロジオン支持膜上にピペットで1滴滴下し、さらに0.02wt%の四酸化オスミウム溶液をピペットでコロジオン支持膜上に1滴滴下し、12時間風乾させ試料を準備した。このようにして準備した試料を、透過型電子顕微鏡(TEM、株式会社日立ハイテクノロジーズ製、型番「H-7650」)を用いて、倍率を10K(倍率)で観察し、HITACH EMIPのプログラムにより画像解析を実施し、ランダムに選択した50個の重合体粒子(A1)の数平均粒子径を算出したところ、100nmであった。
(2) Measurement of Number Average Particle Size One drop of the latex obtained by diluting the composition for an electricity storage device obtained above to 0.1 wt% was dropped on a collodion support membrane by a pipette, and further, 0.02 wt% of osmium tetroxide was added. One drop of the solution was dropped on the collodion support membrane with a pipette, and air-dried for 12 hours to prepare a sample. The sample thus prepared was observed at a magnification of 10K (magnification) using a transmission electron microscope (TEM, manufactured by Hitachi High-Technologies Corporation, model number "H-7650"), and imaged by a program of HITACH EMIP. Analysis was performed, and the number average particle diameter of 50 randomly selected polymer particles (A1) was calculated to be 100 nm.
(3)pHの測定
 上記で得られた蓄電デバイス用組成物について、pHメーター(株式会社堀場製作所製)を用いて25℃におけるpHを測定したところ、pH9.0であることを確認できた。
(3) Measurement of pH The pH of the composition for an electric storage device obtained above was measured at 25 ° C. using a pH meter (manufactured by Horiba, Ltd.), and it was confirmed that the pH was 9.0.
(4)粘度の測定
 上記で得られた蓄電デバイス用組成物について、B型粘度計を用いて25℃における粘度を測定したところ、10,000mPa・sであった。
(4) Measurement of Viscosity The viscosity of the composition for an electricity storage device obtained above was measured at 25 ° C. using a B-type viscometer, and found to be 10,000 mPa · s.
(5)Tgの測定
 上記で得られた蓄電デバイス用組成物について、JIS K7121に準拠する示差走査熱量計(NETZSCH社製、DSC204F1 Phoenix)を用いて測定したところ、重合体(A1)の吸熱ピークが100℃に1つ観測された。
(5) Measurement of Tg The composition for an electricity storage device obtained above was measured using a differential scanning calorimeter (DSC204F1 Phoenix, manufactured by NETZSCH) according to JIS K7121, and the endothermic peak of the polymer (A1) was obtained. Was observed at 100 ° C.
 5.1.2.蓄電デバイス電極用スラリーの調製及び評価
(1)ケイ素材料(活物質)の合成
 粉砕した二酸化ケイ素粉末(平均粒子径10μm)と炭素粉末(平均粒子径35μm)との混合物を、温度を1100~1600℃の範囲に調整した電気炉中で、窒素気流下(0.5NL/分)、10時間の加熱処理を行い、組成式SiO(x=0.5~1.1)で表される酸化ケイ素の粉末(平均粒子径8μm)を得た。この酸化ケイ素の粉末300gをバッチ式加熱炉内に仕込み、真空ポンプにより絶対圧100Paの減圧を維持しながら、300℃/hの昇温速度にて室温(25℃)から1100℃まで昇温した。次いで、加熱炉内の圧力を2000Paに維持しつつ、メタンガスを0.5NL/分の流速にて導入しながら、1100℃、5時間の加熱処理(黒鉛被膜処理)を行った。黒鉛被膜処理終了後、50℃/hの降温速度で室温まで冷却することにより、黒鉛被膜酸化ケイ素の粉末約330gを得た。この黒鉛被膜酸化ケイ素は、酸化ケイ素の表面が黒鉛で被覆された導電性の粉末(活物質)であり、その平均粒子径は10.5μmであり、得られた黒鉛被膜酸化ケイ素の全体を100質量%とした場合の黒鉛被膜の割合は2質量%であった。
5.1.2. Preparation and evaluation of slurry for power storage device electrode (1) Synthesis of silicon material (active material) A mixture of pulverized silicon dioxide powder (average particle diameter 10 μm) and carbon powder (average particle diameter 35 μm) was heated at a temperature of 1100 to 1600. In an electric furnace adjusted to the range of ° C., a heat treatment was performed for 10 hours under a nitrogen stream (0.5 NL / min), and oxidation represented by the composition formula SiO x (x = 0.5 to 1.1) was performed. A silicon powder (average particle diameter: 8 μm) was obtained. 300 g of this silicon oxide powder was charged into a batch heating furnace, and the temperature was raised from room temperature (25 ° C.) to 1100 ° C. at a rate of 300 ° C./h while maintaining a reduced pressure of 100 Pa absolute by a vacuum pump. . Next, a heat treatment (graphite film treatment) was performed at 1100 ° C. for 5 hours while introducing methane gas at a flow rate of 0.5 NL / min while maintaining the pressure in the heating furnace at 2000 Pa. After the completion of the graphite coating treatment, the mixture was cooled to room temperature at a rate of 50 ° C./h to obtain about 330 g of graphite-coated silicon oxide powder. This graphite-coated silicon oxide is a conductive powder (active material) in which the surface of the silicon oxide is coated with graphite, the average particle diameter is 10.5 μm, and the obtained graphite-coated silicon oxide is 100% in total. The ratio of the graphite coating in the case of mass% was 2 mass%.
(2)蓄電デバイス電極用スラリーの調製
 二軸型プラネタリーミキサー(プライミクス株式会社製、商品名「TKハイビスミックス 2P-03」)に重合体(A1)を4質量部(固形分換算値、上記で得られた蓄電デバイス用組成物として添加)、負極活物質として結晶性の高いグラファイトである人造黒鉛(日立化成工業株式会社製、商品名「MAG」)76質量部(固形分換算値)、上記で得られた黒鉛被覆膜酸化ケイ素の粉末を19質量部(固形分換算値)、導電付与剤であるカーボン(デンカ株式会社製、アセチレンブラック)を1質量部を投入し、60rpmで1時間攪拌を行い、ペーストを得た。得られたペーストに水を投入し、固形分濃度を48質量%に調整した後、攪拌脱泡機(株式会社シンキー製、商品名「泡とり練太郎」)を使用して、200rpmで2分間、1800rpmで5分間、さらに減圧下(約2.5×10Pa)において1800rpmで1.5分間攪拌混合することにより、負極活物質中にSiを20質量%含有する蓄電デバイス電極用スラリー(C/Si(20%))を調製した。
(2) Preparation of slurry for electrode of electricity storage device In a biaxial planetary mixer (manufactured by Primix Co., Ltd., trade name “TK Hibismix 2P-03”), 4 parts by mass of the polymer (A1) (solid content equivalent, ), 76 parts by mass (solid content converted value) of artificial graphite (manufactured by Hitachi Chemical Co., Ltd., trade name “MAG”), which is graphite having high crystallinity as a negative electrode active material, 19 parts by mass of the above-obtained graphite-coated silicon oxide powder (in terms of solid content) and 1 part by mass of carbon (acetylene black manufactured by Denka Corporation) as a conductivity-imparting agent were charged, and 1 part at 60 rpm. The mixture was stirred for a time to obtain a paste. Water was added to the obtained paste, the solid content concentration was adjusted to 48% by mass, and then, using a stirring defoaming machine (trade name “Awatori Neritaro”, manufactured by Shinky Corporation) at 200 rpm for 2 minutes. By stirring and mixing at 1800 rpm for 5 minutes and further under reduced pressure (about 2.5 × 10 4 Pa) at 1800 rpm for 1.5 minutes, a slurry for an electricity storage device electrode containing 20% by mass of Si in the negative electrode active material ( C / Si (20%)).
 5.1.3.蓄電デバイスの製造及び評価
(1)蓄電デバイス電極(負極)の製造
 厚み20μmの銅箔よりなる集電体の表面に、上記で得られた蓄電デバイス電極用スラリー(C/Si(20%))を、乾燥後の膜厚が80μmとなるようにドクターブレード法によって均一に塗布し、60℃で10分乾燥し、次いで120℃で10分乾燥処理した。その後、活物質層の密度が1.5g/cmとなるようにロールプレス機によりプレス加工することにより、蓄電デバイス電極(負極)を得た。
5.1.3. Production and evaluation of electricity storage device (1) Production of electricity storage device electrode (negative electrode) On the surface of a current collector made of a copper foil having a thickness of 20 μm, the slurry for electricity storage device electrode obtained above (C / Si (20%)) Was uniformly applied by a doctor blade method so that the film thickness after drying was 80 μm, dried at 60 ° C. for 10 minutes, and then dried at 120 ° C. for 10 minutes. Thereafter, the active material layer was pressed with a roll press so that the density of the active material layer became 1.5 g / cm 3 , thereby obtaining an electricity storage device electrode (negative electrode).
(2)負極塗工層の密着強度の評価
 上記で得られた電極シートの表面に、ナイフを用いて活物質層から集電体に達する深さまでの切り込みを2mm間隔で縦横それぞれ10本入れて碁盤目の切り込みを作った。この切り込みに幅18mmの粘着テープ(ニチバン(株)製、商品名「セロテープ」(登録商標)JIS Z1522に規定)を貼り付けて直ちに引き剥がし、活物質の脱落の程度を目視判定で評価した。評価基準は以下の通りである。評価結果を表1に示す。
(評価基準)
・5点:活物質層の脱落が0個である。
・4点:活物質層の脱落が1~5個である。
・3点:活物質層の脱落が6~20個である。
・2点:活物質層の脱落が21~40個である。
・1点:活物質層の脱落が41個以上である。
(2) Evaluation of Adhesion Strength of Negative Coating Layer On the surface of the electrode sheet obtained above, ten notches were vertically and horizontally cut at a distance of 2 mm from the active material layer to the current collector using a knife. I made a cut in the grid. An adhesive tape having a width of 18 mm (trade name of “Cellotape” (registered trademark), JIS Z1522, manufactured by Nichiban Co., Ltd.) was adhered to the cut, immediately peeled off, and the degree of falling off of the active material was visually evaluated. The evaluation criteria are as follows. Table 1 shows the evaluation results.
(Evaluation criteria)
5 points: No active material layer was dropped.
4 points: 1 to 5 active material layers fall off.
3 points: 6 to 20 active material layers fall off.
2 points: 21 to 40 active material layers fall off.
1 point: 41 or more active material layers were dropped.
(3)対極(正極)の製造
 二軸型プラネタリーミキサー(プライミクス株式会社製、商品名「TKハイビスミックス 2P-03」)に、電気化学デバイス電極用バインダー(株式会社クレハ製、商品名「KFポリマー#1120」、以下「PVDF」と略す。)4.0質量部(固形分換算値)、導電助剤(デンカ株式会社製、商品名「デンカブラック50%プレス品」)3.0質量部、正極活物質として平均粒子径5μmのLiCoO(ハヤシ化成株式会社製)100質量部(固形分換算値)及びN-メチルピロリドン(NMP)36質量部を投入し、60rpmで2時間攪拌を行った。得られたペーストにNMPを追加し、固形分濃度を65質量%に調整した後、攪拌脱泡機(株式会社シンキー製、商品名「泡とり練太郎」)を使用して、200rpmで2分間、1,800rpmで5分間、さらに減圧下(約2.5×10Pa)において1,800rpmで1.5分間攪拌混合することにより、正極用スラリーを調製した。アルミニウム箔よりなる集電体の表面に、この正極用スラリーを、溶媒除去後の膜厚が80μmとなるようにドクターブレード法によって均一に塗布し、120℃で20分間加熱して溶媒を除去した。その後、活物質層の密度が3.0g/cmとなるようにロールプレス機によりプレス加工することにより、対極(正極)を得た。
(3) Production of Counter Electrode (Positive Electrode) A biaxial planetary mixer (manufactured by Primix Co., Ltd., trade name "TK Hibismix 2P-03") was added to a binder for an electrochemical device electrode (Kureha Corporation, trade name "KF"). "Polymer # 1120", hereinafter abbreviated as "PVDF") 4.0 parts by mass (in terms of solid content), 3.0 parts by mass of conductive aid (trade name "DENKA BLACK 50% pressed product" manufactured by Denka Corporation) Then, 100 parts by mass of LiCoO 2 (manufactured by Hayashi Kasei Co., Ltd.) having an average particle diameter of 5 μm (solid content converted value) and 36 parts by mass of N-methylpyrrolidone (NMP) were charged as the positive electrode active material, and the mixture was stirred at 60 rpm for 2 hours. Was. After adding NMP to the obtained paste and adjusting the solid content concentration to 65% by mass, using a stirring defoaming machine (trade name “Awatori Neritaro” manufactured by Shinky Corporation) at 200 rpm for 2 minutes. The slurry for positive electrode was prepared by stirring and mixing at 1,800 rpm for 5 minutes and further under reduced pressure (about 2.5 × 10 4 Pa) at 1,800 rpm for 1.5 minutes. This positive electrode slurry was uniformly applied to the surface of the current collector made of aluminum foil by a doctor blade method so that the film thickness after solvent removal was 80 μm, and heated at 120 ° C. for 20 minutes to remove the solvent. . Thereafter, a counter electrode (positive electrode) was obtained by pressing with a roll press machine so that the density of the active material layer was 3.0 g / cm 3 .
(4)リチウムイオン電池セルの組立て
 露点が-80℃以下となるようAr置換されたグローブボックス内で、上記で製造した負極を直径15.95mmに打ち抜き成形したものを、2極式コインセル(宝泉株式会社製、商品名「HSフラットセル」)上に載置した。次いで、直径24mmに打ち抜いたポリプロピレン製多孔膜からなるセパレータ(セルガード株式会社製、商品名「セルガード#2400」)を載置し、さらに、空気が入らないように電解液を500μL注入した後、上記で製造した正極を直径16.16mmに打ち抜き成形したものを載置し、前記2極式コインセルの外装ボディーをネジで閉めて封止することにより、リチウムイオン電池セル(蓄電デバイス)を組み立てた。ここで使用した電解液は、エチレンカーボネート/エチルメチルカーボネート=1/1(質量比)の溶媒に、LiPFを1モル/Lの濃度で溶解した溶液である。
(4) Assembly of Lithium-ion Battery Cell A negative electrode manufactured as described above was punched out to a diameter of 15.95 mm in an Ar-substituted glove box so that the dew point would be −80 ° C. or less. Izumi Co., Ltd., trade name "HS Flat Cell"). Next, a separator (made by Celgard Co., Ltd., trade name “Celgard # 2400”) made of a polypropylene porous membrane punched to a diameter of 24 mm was placed, and 500 μL of an electrolyte was further injected so that air did not enter. A lithium ion battery cell (power storage device) was assembled by mounting a positive electrode manufactured by punching out to a diameter of 16.16 mm, and closing the external body of the two-pole type coin cell with screws and sealing. The electrolytic solution used here is a solution in which LiPF 6 is dissolved at a concentration of 1 mol / L in a solvent of ethylene carbonate / ethyl methyl carbonate = 1/1 (mass ratio).
(5)充放電サイクル特性の評価
 上記で製造した蓄電デバイスにつき、25℃に調温された恒温槽にて、定電流(1.0C)にて充電を開始し、電圧が4.2Vになった時点で引き続き定電圧(4.2V)にて充電を続行し、電流値が0.01Cとなった時点を充電完了(カットオフ)とした。その後、定電流(1.0C)にて放電を開始し、電圧が3.0Vになった時点を放電完了(カットオフ)とし、1サイクル目の放電容量を算出した。このようにして100回充放電を繰り返した。下記式により容量保持率を計算し、下記の基準で評価した。評価結果を表1に示す。
 容量保持率(%)=(100サイクル目の放電容量)/(1サイクル目の放電容量)
(評価基準)
・5点:容量保持率が95%以上。
・4点:容量保持率が90%以上~95%未満。
・3点:容量保持率が85%以上~90%未満。
・2点:容量保持率が80%以上~85%未満。
・1点:容量保持率が75%以上~80%未満。
・0点:容量保持率が75%未満。
(5) Evaluation of charge / discharge cycle characteristics The charge storage device manufactured above was charged at a constant current (1.0 C) in a constant temperature bath adjusted to 25 ° C., and the voltage became 4.2 V. At this point, charging was continued at a constant voltage (4.2 V), and when the current value reached 0.01 C, charging was completed (cut off). After that, discharging was started at a constant current (1.0 C), and when the voltage reached 3.0 V, discharging was completed (cut off), and the discharge capacity in the first cycle was calculated. Thus, charging and discharging were repeated 100 times. The capacity retention was calculated by the following formula, and evaluated according to the following criteria. Table 1 shows the evaluation results.
Capacity retention (%) = (discharge capacity at 100th cycle) / (discharge capacity at 1st cycle)
(Evaluation criteria)
5 points: capacity retention rate is 95% or more.
4 points: Capacity retention is 90% or more and less than 95%.
3 points: Capacity retention is 85% or more and less than 90%.
2 points: Capacity retention is 80% or more and less than 85%.
1 point: Capacity retention is 75% or more and less than 80%.
0 point: capacity retention is less than 75%.
 なお、測定条件において「1C」とは、ある一定の電気容量を有するセルを定電流放電して1時間で放電終了となる電流値のことを示す。例えば「0.1C」とは、10時間かけて放電終了となる電流値のことであり、「10C」とは、0.1時間かけて放電完了となる電流値のことをいう。 In the measurement conditions, “1C” indicates a current value at which a cell having a certain electric capacity is discharged at a constant current and discharge is completed in one hour. For example, “0.1 C” refers to a current value at which discharge is completed in 10 hours, and “10 C” refers to a current value at which discharge is completed in 0.1 hours.
 5.2.実施例2~26、比較例1~10
 上記「5.1.1.蓄電デバイス用組成物の調製及び評価 (1)蓄電デバイス用組成物の調製」において、各単量体の種類及び量を、それぞれ下表1または下表2に記載の通りとした以外は同様にして重合体成分を20質量%含有する蓄電デバイス用組成物を得た。なお、本明細書において、実施例1で得られた重合体粒子(A)を「重合体粒子(A1)」と呼称し、同様に、実施例5で得られた重合体粒子(A)を「重合体粒子(A5)」、実施例19で得られた重合体粒子(A)を「重合体粒子(A19)」などと呼称する。また、比較例1で得られた重合体粒子を「重合体粒子(B1)」と呼称し、同様に、比較例9で得られた重合体粒子を「重合体粒子(B9)」などと呼称する。
5.2. Examples 2 to 26, Comparative Examples 1 to 10
In the above “5.1.1. Preparation and evaluation of composition for power storage device (1) Preparation of composition for power storage device”, the type and amount of each monomer are described in Table 1 or Table 2 below, respectively. A composition for an electricity storage device containing 20% by mass of a polymer component was obtained in the same manner as described above. In the present specification, the polymer particles (A) obtained in Example 1 are referred to as “polymer particles (A1)”, and similarly, the polymer particles (A) obtained in Example 5 are referred to as “polymer particles (A)”. The “polymer particles (A5)” and the polymer particles (A) obtained in Example 19 are referred to as “polymer particles (A19)” and the like. Further, the polymer particles obtained in Comparative Example 1 are referred to as “polymer particles (B1)”, and similarly, the polymer particles obtained in Comparative Example 9 are referred to as “polymer particles (B9)”. I do.
 さらに、上記で調製した蓄電デバイス用組成物を用いた以外は上記実施例1と同様にして、蓄電デバイス電極用スラリーをそれぞれ調製し、蓄電デバイス電極及び蓄電デバイスをそれぞれ作製し、上記実施例1と同様に評価した。 Further, in the same manner as in Example 1 except that the composition for an electricity storage device prepared above was used, a slurry for an electricity storage device electrode was prepared, and an electricity storage device electrode and an electricity storage device were prepared, respectively. Was evaluated in the same manner as described above.
 5.3.実施例32
 実施例5と同様にして重合体粒子(A5)を20質量%含有するpH9.0の蓄電デバイス用組成物を得た。次いで、二軸型プラネタリーミキサー(プライミクス株式会社製、商品名「TKハイビスミックス 2P-03」)に、先添加成分として、増粘剤(商品名「CMC2200」、株式会社ダイセル製)を1質量部(固形分換算値、濃度2質量%の水溶液として添加)、重合体粒子(A5)を1質量部(固形分換算値、上記で得られた重合体粒子(A5)を20質量%含有するpH9.0の蓄電デバイス用組成物として添加)、負極活物質として結晶性の高いグラファイトである人造黒鉛(日立化成工業株式会社製、商品名「MAG」)を76質量部(固形分換算値)、上記で得られた黒鉛被覆膜酸化ケイ素の粉末を19質量部(固形分換算値)、導電付与剤であるカーボン(デンカ株式会社製、アセチレンブラック)を1質量部投入し、60rpmで1時間攪拌を行った。次いで、後添加成分としてSBR(商品名「TRD105A」、JSR株式会社製)を2質量部(固形分換算値)に相当する量だけ加え、さらに1時間攪拌しペーストを得た。得られたペーストに水を投入し、固形分濃度を48質量%に調整した後、攪拌脱泡機(株式会社シンキー製、商品名「泡とり練太郎」)を使用して、200rpmで2分間、1800rpmで5分間、さらに減圧下(約2.5×10Pa)において1800rpmで1.5分間攪拌混合することにより、負極活物質中にSiを20質量%含有する蓄電デバイス電極用スラリー(C/Si(20%))を調製した。
5.3. Example 32
In the same manner as in Example 5, a composition for an electric storage device having a pH of 9.0 and containing 20% by mass of the polymer particles (A5) was obtained. Next, 1 mass of a thickener (trade name "CMC2200", manufactured by Daicel Co., Ltd.) was added as a first component to a twin-shaft planetary mixer (trade name "TK Hibismix 2P-03" manufactured by Primix Co., Ltd.). Parts (as solid content, added as an aqueous solution having a concentration of 2% by mass), and 1 part by mass of polymer particles (A5) (solids equivalent, containing 20% by mass of polymer particles (A5) obtained above). 76 parts by mass (solid content converted value) of artificial graphite (manufactured by Hitachi Chemical Co., Ltd., trade name "MAG") which is graphite having high crystallinity as a negative electrode active material (added as a composition for a power storage device having a pH of 9.0). Then, 19 parts by mass (solid content converted value) of the above-obtained graphite-coated silicon oxide powder and 1 part by mass of carbon (acetylene black, manufactured by Denka Corporation) as a conductivity-imparting agent were charged, and 60 r. Stirring was performed at pm for 1 hour. Next, SBR (trade name “TRD105A”, manufactured by JSR Corporation) was added as an after-addition component in an amount corresponding to 2 parts by mass (solid content conversion value), and the mixture was further stirred for 1 hour to obtain a paste. Water was added to the obtained paste, the solid content concentration was adjusted to 48% by mass, and then, using a stirring defoaming machine (trade name “Awatori Neritaro”, manufactured by Shinky Corporation) at 200 rpm for 2 minutes. By stirring and mixing at 1800 rpm for 5 minutes and further under reduced pressure (about 2.5 × 10 4 Pa) at 1800 rpm for 1.5 minutes, a slurry for an electricity storage device electrode containing 20% by mass of Si in the negative electrode active material ( C / Si (20%)).
 上記で調製した蓄電デバイス電極用スラリーを用いた以外は上記実施例1と同様にして、蓄電デバイス電極及び蓄電デバイスをそれぞれ作製し、上記実施例1と同様に評価した。 電 An electricity storage device electrode and an electricity storage device were prepared in the same manner as in Example 1 except that the slurry for an electricity storage device electrode prepared above was used, and evaluated in the same manner as in Example 1.
 5.4.実施例27~31、33、比較例11~17
 蓄電デバイス電極用スラリーの組成を下表3のように変更した以外は上記実施例32と同様にして蓄電デバイス電極用スラリーをそれぞれ調製し、蓄電デバイス電極及び蓄電デバイスをそれぞれ作製し、上記実施例32と同様に評価した。
5.4. Examples 27 to 31, 33 and Comparative Examples 11 to 17
Except that the composition of the slurry for the power storage device electrode was changed as shown in Table 3 below, slurry for the power storage device electrode was prepared in the same manner as in Example 32, and the power storage device electrode and the power storage device were produced. The same evaluation as for No. 32 was made.
 5.5.評価結果
 下表1~下表3に、実施例1~33及び比較例1~17で使用した重合体組成、各物性及び各種評価結果をまとめた。
5.5. Evaluation Results Tables 1 to 3 below summarize the polymer compositions, physical properties, and various evaluation results used in Examples 1 to 33 and Comparative Examples 1 to 17.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
 上表1~上表3における単量体の略称は、それぞれ以下の化合物を表す。
<共役ジエン化合物>
・BD:1,3-ブタジエン
<不飽和カルボン酸>
・TA:イタコン酸
・AA:アクリル酸
・MAA:メタクリル酸
<(メタ)アクリルアミド>
・AAM:アクリルアミド
・MAM:メタクリルアミド
<水酸基を有する不飽和カルボン酸エステル>
・HEMA:メタクリル酸2-ヒドロキシエチル
・HEA:アクリル酸2-ヒドロキシエチル
<不飽和カルボン酸エステル>
・MMA:メタクリル酸メチル
・EDMA:エチレングリコールジメタクリレート
・2EHA:アクリル酸2-エチルヘキシル
<α,β-不飽和ニトリル化合物>
・AN:アクリロニトリル
<芳香族ビニル化合物>
・ST:スチレン
・DVB:ジビニルベンゼン
<スルホン酸基を有する化合物>
・NASS:スチレンスルホン酸ナトリウム
Abbreviations of monomers in Tables 1 to 3 above represent the following compounds, respectively.
<Conjugated diene compound>
・ BD: 1,3-butadiene <unsaturated carboxylic acid>
・ TA: Itaconic acid ・ AA: Acrylic acid ・ MAA: Methacrylic acid <(meth) acrylamide>
AAM: acrylamide MAM: methacrylamide <unsaturated carboxylic acid ester having a hydroxyl group>
-HEMA: 2-hydroxyethyl methacrylate-HEA: 2-hydroxyethyl acrylate <unsaturated carboxylic acid ester>
-MMA: methyl methacrylate-EDMA: ethylene glycol dimethacrylate-2EHA: 2-ethylhexyl acrylate <α, β-unsaturated nitrile compound>
・ AN: Acrylonitrile <Aromatic vinyl compound>
・ ST: Styrene ・ DVB: Divinylbenzene <compound having sulfonic acid group>
・ NASS: Sodium styrenesulfonate
 上表2の比較例3及び比較例4において、数平均粒子径の欄に「-」と表記されているのは、重合体が水に溶解し、粒子形状を発現しなかったため、粒子径が測定できなかったことを表す。 In Comparative Example 3 and Comparative Example 4 in Table 2 above, “-” is indicated in the column of the number average particle diameter because the polymer was dissolved in water and did not exhibit a particle shape. Indicates that measurement could not be performed.
 上表1及び上表2から明らかなように、実施例1~26に示した本発明に係る蓄電デバイス用組成物を用いて調製された蓄電デバイス電極用スラリーは、比較例1~10の場合と比較して、充放電に伴う体積変化が大きい活物質同士を好適に結着させることができ、しかも活物質層と集電体の密着性を良好に維持できることが判明した。その結果、充放電を繰り返して、活物質が体積の膨張と収縮を繰り返したにも関わらず、活物質層の剥離を抑制し、良好な充放電特性を維持し続けることのできる蓄電デバイス電極が得られた。また、これらの蓄電デバイス電極を備える蓄電デバイス(リチウムイオン二次電池)は、充放電レート特性も良好となることが判明した。この理由としては、上表1及び上表2に示す実施例1~26に係る蓄電デバイス電極は、比較例1~10の場合と比較して、充放電による活物質層の膜厚変化を低減できていることにより、活物質層内部の導電ネットワークを維持できるためと推測される。 As is clear from the above Tables 1 and 2, the slurries for electricity storage device electrodes prepared using the electricity storage device compositions according to the present invention shown in Examples 1 to 26 were the same as those in Comparative Examples 1 to 10. It has been found that active materials having a large volume change due to charge / discharge can be preferably bonded to each other as well as good adhesion between the active material layer and the current collector can be maintained. As a result, an energy storage device electrode that can suppress peeling of the active material layer and maintain good charge / discharge characteristics even though the active material repeatedly expands and contracts in volume by repeating charging and discharging. Obtained. In addition, it has been found that a power storage device (lithium ion secondary battery) including these power storage device electrodes also has favorable charge / discharge rate characteristics. The reason for this is that the electricity storage device electrodes according to Examples 1 to 26 shown in Table 1 and Table 2 reduce the change in the thickness of the active material layer due to charging and discharging as compared with Comparative Examples 1 to 10. It is presumed that the formation allows the conductive network inside the active material layer to be maintained.
 また、上表3の結果から明らかなように、実施例27~33に示した本発明に係る蓄電デバイス用組成物を用いて調製された蓄電デバイス電極用スラリーは、比較例11~17の場合と比較して、増粘剤や他の重合体を併用しても、充放電に伴う体積変化が大きい活物質同士を好適に結着させることができ、しかも活物質層と集電体の密着性を良好に維持できることが判明した。 Further, as is clear from the results in Table 3 above, the slurry for an electricity storage device electrode prepared using the composition for an electricity storage device according to the present invention shown in Examples 27 to 33 was the same as that of Comparative Examples 11 to 17. Compared with the above, even when a thickener or another polymer is used in combination, active materials having a large volume change due to charge / discharge can be preferably bonded to each other, and furthermore, the adhesion between the active material layer and the current collector can be improved. It was found that the properties could be maintained well.
 本発明は、上記の実施形態に限定されるものではなく、種々の変形が可能である。本発明は、実施形態で説明した構成と実質的に同一の構成(例えば、機能、方法および結果が同一の構成、あるいは目的および効果が同一の構成)を包含する。また本発明は、上記の実施形態で説明した構成の本質的でない部分を他の構成に置き換えた構成を包含する。さらに本発明は、上記の実施形態で説明した構成と同一の作用効果を奏する構成または同一の目的を達成することができる構成をも包含する。さらに本発明は、上記の実施形態で説明した構成に公知技術を付加した構成をも包含する。
 
The present invention is not limited to the above embodiment, and various modifications are possible. 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 object and effect). The invention also includes a configuration in which a non-essential part of the configuration described in the above embodiment is replaced with another configuration. Further, the invention also includes a configuration having the same function and effect as the configuration described in the above embodiment, or a configuration capable of achieving the same object. Further, the invention also includes a configuration obtained by adding a known technique to the configuration described in the above embodiment.

Claims (10)

  1.  重合体粒子(A)と、液状媒体(B)と、を含有し、
     前記重合体粒子(A)の数平均粒子径が50nm以上500nm以下であり、
     前記重合体粒子(A)中に含まれる繰り返し単位の合計を100質量部としたときに、前記重合体粒子(A)が、
     共役ジエン化合物に由来する繰り返し単位(a1)1~50質量部と、
     不飽和カルボン酸に由来する繰り返し単位(a2)5~90質量部と、
     (メタ)アクリルアミドに由来する繰り返し単位(a3)5~90質量部と、を含有し、
     前記繰り返し単位(a2)と前記繰り返し単位(a3)の合計量が50質量部以上である、蓄電デバイス用組成物。
    It contains polymer particles (A) and a liquid medium (B),
    The number average particle diameter of the polymer particles (A) is 50 nm or more and 500 nm or less;
    When the total of the repeating units contained in the polymer particles (A) is 100 parts by mass, the polymer particles (A) are:
    1 to 50 parts by mass of a repeating unit (a1) derived from a conjugated diene compound,
    5 to 90 parts by mass of a repeating unit (a2) derived from an unsaturated carboxylic acid,
    A repeating unit (a3) derived from (meth) acrylamide in an amount of 5 to 90 parts by mass,
    A composition for an electricity storage device, wherein the total amount of the repeating unit (a2) and the repeating unit (a3) is 50 parts by mass or more.
  2.  pHが6~11である、請求項1に記載の蓄電デバイス用組成物。 The composition for an electricity storage device according to claim 1, wherein the pH is 6 to 11.
  3.  前記重合体粒子(A)の5質量%水分散液のpH9における粘度が、500~150,000mPa・sである、請求項1または請求項2に記載の蓄電デバイス用組成物。 The composition for an electric storage device according to claim 1, wherein the 5% by mass aqueous dispersion of the polymer particles (A) at pH 9 has a viscosity of 500 to 150,000 mPa · s.
  4.  前記液状媒体(B)が水である、請求項1ないし請求項3のいずれか一項に記載の蓄電デバイス用組成物。 The composition for an electricity storage device according to any one of claims 1 to 3, wherein the liquid medium (B) is water.
  5.  請求項1ないし請求項4のいずれか一項に記載の蓄電デバイス用組成物と、活物質と、を含有する蓄電デバイス電極用スラリー。 A slurry for an electrode of an electricity storage device, comprising the composition for an electricity storage device according to any one of claims 1 to 4, and an active material.
  6.  前記活物質としてケイ素材料を含有する、請求項5に記載の蓄電デバイス電極用スラリー。 The slurry for an electrode of a power storage device according to claim 5, wherein the slurry contains a silicon material as the active material.
  7.  スチレン-ブタジエン共重合体、アクリル系重合体及びフッ素系重合体からなる群より選択される少なくとも1種の重合体をさらに含有する、請求項5または請求項6に記載の蓄電デバイス電極用スラリー。 7. The slurry for an electrode of an electricity storage device according to claim 5, further comprising at least one polymer selected from the group consisting of a styrene-butadiene copolymer, an acrylic polymer, and a fluoropolymer.
  8.  増粘剤をさらに含有する、請求項5ないし請求項7のいずれか一項に記載の蓄電デバイス電極用スラリー。 The slurry for an electrode of a power storage device according to any one of claims 5 to 7, further comprising a thickener.
  9.  集電体と、前記集電体の表面上に請求項5ないし請求項8のいずれか一項に記載の蓄電デバイス電極用スラリーが塗布及び乾燥されて形成された活物質層と、を備える蓄電デバイス電極。 A power storage device comprising: a current collector; and an active material layer formed by applying and drying the slurry for a power storage device electrode according to any one of claims 5 to 8 on a surface of the current collector. Device electrode.
  10.  請求項9に記載の蓄電デバイス電極を備える蓄電デバイス。
     
    An electricity storage device comprising the electricity storage device electrode according to claim 9.
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