Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
  • C08F212/02—Monomers containing only one unsaturated aliphatic radical
  • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
  • C08F212/06—Hydrocarbons
  • C08F212/08—Styrene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/10—Esters
  • C08F220/12—Esters of monohydric alcohols or phenols
  • C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
  • C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
  • C08F220/1808—C8-(meth)acrylate, e.g. isooctyl (meth)acrylate or 2-ethylhexyl (meth)acrylate
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D125/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Coating compositions based on derivatives of such polymers
  • C09D125/02—Homopolymers or copolymers of hydrocarbons
  • C09D125/04—Homopolymers or copolymers of styrene
  • C09D125/08—Copolymers of styrene
  • C09D125/14—Copolymers of styrene with unsaturated esters
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
  • C09D133/04—Homopolymers or copolymers of esters
  • C09D133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
  • C09D133/062—Copolymers with monomers not covered by C09D133/06
  • C09D133/064—Copolymers with monomers not covered by C09D133/06 containing anhydride, COOH or COOM groups, with M being metal or onium-cation
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/24—Electrically-conducting paints
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/60—Additives non-macromolecular
  • C09D7/61—Additives non-macromolecular inorganic
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
  • H01G11/22—Electrodes
  • H01G11/26—Electrodes characterised by their structure, e.g. multi-layered, porosity or surface features
  • H01G11/28—Electrodes characterised by their structure, e.g. multi-layered, porosity or surface features arranged or disposed on a current collector; Layers or phases between electrodes and current collectors, e.g. adhesives
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
  • H01G11/22—Electrodes
  • H01G11/30—Electrodes characterised by their material
  • H01G11/32—Carbon-based
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
  • H01G11/22—Electrodes
  • H01G11/30—Electrodes characterised by their material
  • H01G11/32—Carbon-based
  • H01G11/38—Carbon pastes or blends; Binders or additives therein
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
  • H01G11/22—Electrodes
  • H01G11/30—Electrodes characterised by their material
  • H01G11/50—Electrodes characterised by their material specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
  • H01G11/84—Processes for the manufacture of hybrid or EDL capacitors, or components thereof
  • H01G11/86—Processes for the manufacture of hybrid or EDL capacitors, or components thereof specially adapted for electrodes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
  • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
  • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
  • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
  • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
  • H01M4/621—Binders
  • H01M4/622—Binders being polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2800/00—Copolymer characterised by the proportions of the comonomers expressed
  • C08F2800/20—Copolymer characterised by the proportions of the comonomers expressed as weight or mass percentages
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
  • H01G11/04—Hybrid capacitors
  • H01G11/06—Hybrid capacitors with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the present invention relates to a binder composition for a power storage device, a slurry for a power storage device electrode, a power storage device electrode, and a power storage device.
• Lithium ion batteries, lithium ion capacitors, and the like are expected to be used as such power storage devices.
• Electrodes used in such power storage devices are manufactured by applying a composition (slurry for power storage device electrodes) containing an active material and a polymer that functions as a binder onto the surface of a current collector and drying the composition.
• a composition slurry for power storage device electrodes
• a polymer that functions as a binder onto the surface of a current collector and drying the composition.
• Ru Properties required of a polymer used as a binder include the ability to bond between active materials and the ability to adhere to an active material and a current collector. Another example is powder drop resistance, which prevents fine particles of the active material from falling off from the active material layer when the coated and dried composition coating film (hereinafter also referred to as "active material layer”) is cut.
• active material layer Such a binder material exhibits good adhesion and reduces the internal resistance of the battery caused by the binder material, thereby imparting good charge/discharge characteristics to the electricity storage device.
• PVDF polyvinylidene fluoride
• Some embodiments of the present invention are a water-based binder that can produce a power storage device electrode with excellent adhesion and flexibility, and can reduce an increase in internal resistance of the power storage device and improve cycle characteristics.
• a binder composition for devices is provided.
• the present invention has been made to solve at least part of the above-mentioned problems, and can be realized as any of the following embodiments.
• One embodiment of the binder composition for a power storage device is Contains a polymer (A) and a liquid medium (B),
• the polymer (A) is 15 to 64% by mass of repeating units (a1) derived from unsaturated carboxylic esters having an aliphatic hydrocarbon group (excluding unsaturated carboxylic esters having an alicyclic hydrocarbon group); 35 to 84% by mass of repeating units (a2) derived from an aromatic vinyl compound, Contains
• the peak top of tan ⁇ (loss modulus/storage modulus) of the dynamic viscoelasticity of the polymer (A) is only one in the range of -50°C to 0°C and only one in the range of 50°C to 150°C. Appear.
• the polymer (A) may further contain 0.1 to 10% by mass of a repeating unit (a3) derived from an unsaturated carboxylic acid.
• the electrolyte swelling rate is 120% by mass or more and 300% by mass. % or less.
• the polymer (A) is a polymer particle,
• the number average particle diameter of the polymer particles may be 50 nm or more and 500 nm or less.
• the surface acid amount of the polymer particles may be 0.05 mmol/g or more and 2 mmol/g or less.
• One embodiment of the slurry for electricity storage device electrodes according to the present invention is It contains the binder composition for a power storage device according to any of the above embodiments and an active material.
• the active material may contain at least one selected from the group consisting of olivine-type lithium-containing phosphate compounds, lithium cobalt oxides, lithium nickel oxides, lithium manganates, and ternary nickel-cobalt lithium manganates.
• the active material may contain a carbon material.
• the present invention includes a current collector and an active material layer formed by applying and drying the slurry for a power storage device electrode according to one embodiment on the surface of the current collector.
• One embodiment of the power storage device according to the present invention is The power storage device electrode according to the above one embodiment is provided.
• the binder composition for an electricity storage device according to the present invention can be a water-based binder, improves the adhesion and flexibility of the electricity storage device electrode, and reduces the increase in internal resistance of the electricity storage device, improving cycle characteristics. can be done.
• (meth)acrylic acid refers to “acrylic acid” or “methacrylic acid”
• (meth)acrylate refers to “acrylate” or “methacrylate”.
• (meth)acrylamide refers to "acrylamide” or "methacrylamide.”
• a numerical range described as "X to Y" is interpreted as including the numerical value X as the lower limit and the numerical value Y as the upper limit.
• Binder composition for power storage devices contains a polymer (A) and a liquid medium (B).
• the polymer (A) is an unsaturated carboxylic acid ester having an aliphatic hydrocarbon group (an alicyclic hydrocarbon group) when the total number of repeating units contained in the polymer (A) is 100% by mass. 15 to 64% by mass of repeating units (a1) derived from (excluding unsaturated carboxylic acid esters having) and 35 to 84% by mass of repeating units (a2) derived from aromatic vinyl compounds.
• the peak top of tan ⁇ (loss modulus/storage modulus) of the dynamic viscoelasticity of the polymer (A) is one in the range of -50°C to 0°C and one in the range of 50°C to 150°C. Only books appear.
• the binder composition for a power storage device according to the present embodiment is a power storage device electrode (active material layer ), or it can be used as a material for forming a protective film to suppress short circuits caused by dendrites that occur during charging and discharging.
• active material layer active material layer
• the components contained in the binder composition for a power storage device according to the present embodiment will be described in detail.
• the binder composition for a power storage device contains a polymer (A).
• the polymer (A) may be in the form of a latex dispersed in the liquid medium (B), or may be in a state dissolved in the liquid medium (B).
• the polymer (A) is composed of unsaturated carbon atoms having an aliphatic hydrocarbon group when the total number of repeating units contained in the polymer (A) is 100% by mass. 15 to 64% by mass of repeating units (a1) (hereinafter also simply referred to as “repeat units (a1)”) derived from acid esters (excluding unsaturated carboxylic acid esters having an alicyclic hydrocarbon group); The repeating unit (a2) derived from an aromatic vinyl compound (hereinafter also simply referred to as “repeat unit (a2)”) contains 35 to 84% by mass. Moreover, the polymer (A) may contain, in addition to the repeating unit (a1) and the repeating unit (a2), a repeating unit derived from another monomer copolymerizable with these units.
• Repeating unit (a1) derived from an unsaturated carboxylic acid ester having an aliphatic hydrocarbon group does not include the polyfunctional (meth)acrylic acid ester described below and the unsaturated carboxylic acid ester having an alicyclic hydrocarbon group. shall be taken as a thing.
• the content ratio of the repeating unit (a1) derived from the unsaturated carboxylic acid ester having an aliphatic hydrocarbon group is 15 to 15% by mass when the total repeating unit contained in the polymer (A) is 100% by mass. It is 64% by mass.
• the lower limit of the content of the repeating unit (a1) is preferably 15% by mass, more preferably 18% by mass, particularly preferably 20% by mass.
• the upper limit of the content of the repeating unit (a1) is preferably 64% by mass, more preferably 60% by mass, particularly preferably 55% by mass.
• the unsaturated carboxylic acid ester having an aliphatic hydrocarbon group is not particularly limited, but (meth)acrylic acid ester is preferable.
• Specific examples of such (meth)acrylic esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, and (meth)acrylate.
• n-Butyl isobutyl (meth)acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-(meth)acrylate
• examples include ethylhexyl, nonyl (meth)acrylate, and decyl (meth)acrylate, and one or more selected from these can be used.
• one or more selected from methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate are preferable; More preferably, it is one or more selected from n-butyl meth)acrylate and 2-ethylhexyl (meth)acrylate.
• Repeating unit (a2) derived from aromatic vinyl compound The content of the repeating unit (a2) derived from the aromatic vinyl compound is preferably 35 to 84% by mass when the total number of repeating units contained in the polymer (A) is 100% by mass.
• the lower limit of the content of the repeating unit (a2) is preferably 35% by mass, more preferably 40% by mass, particularly preferably 45% by mass.
• the upper limit of the content of the repeating unit (a2) is preferably 84% by mass, more preferably 80% by mass, and particularly preferably 75% by mass.
• the polymer (A) contains the repeating unit (a2) within the above range, it is possible to suppress the fusion between the polymers (A) dispersed in the active material layer and improve the permeability of the electrolytic solution. Therefore, the rise in internal resistance is reduced and good repeated charge/discharge characteristics are exhibited. Furthermore, it exhibits good binding properties to graphite and the like used as an active material, and a power storage device electrode with excellent adhesion can be obtained.
• aromatic vinyl compound examples include, but are not limited to, styrene, ⁇ -methylstyrene, p-methylstyrene, vinyltoluene, chlorostyrene, divinylbenzene, etc., and one or more selected from these may be used. be able to.
• repeating units (a3) derived from unsaturated carboxylic acids (hereinafter also simply referred to as "repeating units (a3)"), and repeating units derived from polyfunctional (meth)acrylic esters.
• repeating unit (a4) (hereinafter also simply referred to as “repeat unit (a4)"), repeating unit (a5) derived from other unsaturated carboxylic acid esters (hereinafter also simply referred to as “repeat unit (a5)”), (metal )
• a repeating unit (a6) derived from acrylamide (hereinafter also simply referred to as “repeat unit (a6)"), a repeating unit (a7) derived from an ⁇ , ⁇ -unsaturated nitrile compound (hereinafter simply referred to as “repeat unit (a7)”)
• a repeating unit (a8) derived from a compound having a sulfonic acid group (hereinafter also simply referred to as a “repeat unit (a8)"), a repeating unit derived from a cationic monomer, and the like.
• the polymer (A) may contain a repeating unit (a3) derived from an unsaturated carboxylic acid.
• unsaturated carboxylic acids include, but are not limited to, monocarboxylic acids and dicarboxylic acids (including anhydrides) such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid. One or more types selected from these can be used.
• unsaturated carboxylic acid it is preferable to use one or more selected from acrylic acid, methacrylic acid, and itaconic acid.
• the content of the repeating unit (a3) derived from unsaturated carboxylic acid may be 0.1 to 10% by mass when the total number of repeating units contained in the polymer (A) is 100% by mass. It is preferably 1 to 8% by mass, and more preferably 1 to 8% by mass.
• the polymer (A) contains the repeating unit (a3) within the above range the dispersibility of the active material and filler becomes good and it becomes possible to produce a homogeneous active material layer and protective film. Structural defects are eliminated, and the battery exhibits good charge-discharge characteristics.
• the polymer (A) may contain a repeating unit (a4) derived from a polyfunctional (meth)acrylic acid ester.
• a4 derived from a polyfunctional (meth)acrylic acid ester.
• polyfunctional refers to one or more functional groups selected from polymerizable double bonds and epoxy groups in addition to one polymerizable double bond that the (meth)acrylic acid ester has. It means that it further has a group.
• polyfunctional (meth)acrylic esters include glycidyl (meth)acrylate, allyl (meth)acrylate, ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, and tri(meth)acrylate.
• examples include trimethylolpropane acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene di(meth)acrylate, and one or more selected from these. can be used.
• one or more selected from allyl (meth)acrylate and ethylene glycol di(meth)acrylate are preferred, and allyl (meth)acrylate is particularly preferred.
• the content ratio of the repeating unit (a4) derived from the polyfunctional (meth)acrylic acid ester is 0.1 to 10% by mass when the total number of repeating units contained in the polymer (A) is 100% by mass.
• the content is preferably 1 to 8% by mass, and more preferably 1 to 8% by mass.
• the polymer (A) may contain repeating units (a5) derived from other unsaturated carboxylic acid esters.
• “other unsaturated carboxylic esters” refer to unsaturated carboxylic esters other than the unsaturated carboxylic esters having an aliphatic hydrocarbon group and the polyfunctional (meth)acrylic esters. .
• unsaturated carboxylic esters include, but are not particularly limited to, unsaturated carboxylic esters having a hydroxyl group, unsaturated carboxylic esters having a phenoxy group, and the like.
• unsaturated carboxylic acid esters having a hydroxyl group include 2-hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 3-hydroxypropyl (meth)acrylate. , 4-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, glycerin mono(meth)acrylate, and the like.
• the unsaturated carboxylic acid ester having a phenoxy group examples include phenoxydiethylene glycol (meth)acrylate and the like.
• the other unsaturated carboxylic acid esters one or more types selected from these can be used. Among these, 2-hydroxyethyl (meth)acrylate and glycerin mono(meth)acrylate are preferred.
• the polymer (A) does not contain a repeating unit derived from an unsaturated carboxylic acid ester having an alicyclic hydrocarbon group.
• the content of repeating units (a5) derived from other unsaturated carboxylic acid esters shall be 0 to 10% by mass when the total number of repeating units contained in the polymer (A) is 100% by mass. is preferable, and more preferably 1 to 8% by mass.
• the polymer (A) contains the repeating unit (a5) within the above range the dispersibility of the active material or filler in the slurry may be improved. Further, the flexibility of the obtained active material layer may be moderate, and the adhesion between the current collector and the active material layer may be improved.
• the polymer (A) may contain a repeating unit (a6) derived from (meth)acrylamide.
• (meth)acrylamide include, but are not limited to, acrylamide, methacrylamide, N-isopropylacrylamide, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N,N-diethylacrylamide, and N,N-diethylmethacrylamide.
• Amide N,N-dimethylaminopropylacrylamide, N,N-dimethylaminopropylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, diacetone acrylamide, maleic acid amide, etc.
• One or more selected types can be used.
• the content ratio of the repeating unit (a6) derived from (meth)acrylamide is preferably 0 to 5% by mass, when the total number of repeating units contained in the polymer (A) is 100% by mass, More preferably, it is 1 to 4% by mass.
• the polymer (A) contains the repeating unit (a6) within the above range the dispersibility of the active material and filler in the slurry may be improved. Further, the flexibility of the resulting active material layer may be moderate, and the adhesion between the current collector and the active material layer may be improved.
• the polymer (A) may contain a repeating unit (a7) derived from an ⁇ , ⁇ -unsaturated nitrile compound.
• a7 derived from an ⁇ , ⁇ -unsaturated nitrile compound.
• the ⁇ , ⁇ -unsaturated nitrile compound include, but are not limited to, acrylonitrile, methacrylonitrile, ⁇ -chloroacrylonitrile, ⁇ -ethyl acrylonitrile, vinylidene cyanide, etc., and one selected from these More than one species can be used. Among these, one or more selected from acrylonitrile and methacrylonitrile are preferred, and acrylonitrile is particularly preferred.
• the content of the repeating unit (a7) derived from the ⁇ , ⁇ -unsaturated nitrile compound is 0 to 10% by mass when the total of repeating units contained in the polymer (A) is 100% by mass. It is preferably 1 to 8% by mass, and more preferably 1 to 8% by mass.
• the polymer (A) contains the repeating unit (a8) within the above range it becomes possible to improve the affinity of the polymer (A) with the electrolytic solution, and facilitates the deintercalation of Li ions. , may exhibit good charge/discharge characteristics.
• the polymer (A) may contain a repeating unit (a8) derived from a compound having a sulfonic acid group.
• a repeating unit (a8) derived from a compound having a sulfonic acid group examples include, but are not limited to, vinyl sulfonic acid, styrene sulfonic acid, allyl sulfonic acid, sulfoethyl (meth)acrylate, sulfopropyl (meth)acrylate, sulfobutyl (meth)acrylate, and 2-acrylamide-2.
• the content of the repeating unit (a8) derived from a compound having a sulfonic acid group may be 0 to 10% by mass, when the total number of repeating units contained in the polymer (A) is 100% by mass. Preferably, 1 to 6% by mass is more preferable.
• the polymer (A) contains the repeating unit (a8) within the above range the dispersibility of the active material and filler becomes good and it becomes possible to produce a homogeneous active material layer and protective film. In some cases, structural defects are eliminated and good charge/discharge characteristics are exhibited.
• the polymer (A) may contain repeating units derived from a cationic monomer.
• the cationic monomer is not particularly limited, but at least one monomer selected from the group consisting of secondary amines (salts), tertiary amines (salts), and quaternary ammonium salts. It is preferable that there be.
• Examples of the cationic monomer include, but are not limited to, 2-(dimethylamino)ethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate methyl chloride quaternary salt, and 2-(diethylamino)ethyl (meth)acrylate.
• the measurement sample in this dynamic viscoelasticity measurement is a film of polymer (A).
• the polymer (A) film was prepared by drying the polymer (A) at 40°C for 24 hours to produce a uniform film with a thickness of 1.0 ⁇ 0.3mm, and drying this film at 160°C in a vacuum dryer. After drying for 30 minutes, it was cut into strips of 10 mm x 10 mm.
• the measurement sample is fixed on a parallel plate (product name "PP-12"), and the measurement is performed in the temperature range of -70°C to 180°C under the following measurement conditions.
• the temperature Tp1 (°C) of the peak top on the low temperature side among the tan ⁇ peak tops in the dynamic viscoelasticity measurement of the polymer (A) is preferably -50°C to 0°C, more preferably -48°C to -3°C.
• the temperature range is preferably from -45°C to -5°C.
• the presence of one peak top in the above temperature range indicates that the viscosity is high in the same temperature range. It is thought that this high viscosity allows the polymer (A) to maintain a high binding force in the same temperature range and to develop good adhesion. Furthermore, the flexibility of the electrode can be improved, and it is thought that a power storage device exhibiting good charge/discharge characteristics can be obtained.
• the temperature Tp2 (°C) of the peak top on the high temperature side among the peak tops of tan ⁇ in the dynamic viscoelasticity measurement of the polymer (A) is preferably 50°C to 150°C, more preferably 60°C to 145°C, particularly preferably is preferably present in a temperature range of 70°C to 140°C.
• the presence of one peak top in the above temperature range indicates that a polymer with a uniform crosslinked composition is formed in the same temperature range.
• This high viscosity indicates that the amount of uniform crosslinking composition of the polymer (A) is large in the same temperature range, and it is thought that the hardness of the polymer (A) can be expressed and the increase in internal resistance can be reduced.
• Examples of the method for adjusting the peak top temperatures Tp1 and Tp2 of tan ⁇ include a method of adjusting the monomer composition during polymerization of the polymer (A).
• Electrolyte swelling rate Swelling rate when the polymer (A) is immersed in a solvent consisting of propylene carbonate and diethyl carbonate at a volume fraction of 1:1 at 70°C for 24 hours is preferably 120% by mass or more and 300% by mass or less, more preferably 130% by mass or more and 280% by mass or less, particularly preferably 140% by mass or more and 250% by mass or less. It is.
• the electrolytic solution swelling rate of the polymer (A) is within the above range, the polymer (A) can appropriately swell by absorbing the electrolytic solution. As a result, solvated lithium ions can easily reach the active material.
• the electrolytic solution swelling ratio is within the above range, the polymer (A) will have poor coverage of the active material, effectively lowering the electrode resistance and exhibiting good charge/discharge characteristics.
• the number average particle diameter of the particles is preferably 50 nm or more and 500 nm or less, more preferably 60 nm or more and 450 nm or less, particularly preferably 70 nm or more and 400 nm or less. It is as follows. When the number average particle diameter of the particles of the polymer (A) is within the above range, the particles of the polymer (A) are easily adsorbed onto the surface of the active material, so that the particles of the polymer (A) are easily absorbed as the active material moves. ) particles can also follow and move. As a result, migration can be suppressed, so deterioration of electrical characteristics can be reduced in some cases.
• the number average particle diameter of the polymer (A) can be measured by the method described in Examples below.
• the surface acid content of the particles is preferably 0.05 mmol/g or more and 2 mmol/g or less, more preferably 0.1 mmol/g or more and 1.8 mmol /g or less, particularly preferably from 0.15 mmol/g to 1.5 mmol/g.
• the surface acid amount of the particles of the polymer (A) is within the above range, a stable and homogeneous slurry can be produced.
• an active material layer is produced using such a homogeneous slurry, an active material layer with small thickness variations in which the active material and particles of the polymer (A) are uniformly dispersed can be obtained. As a result, variations in charging and discharging characteristics within the electrode can be suppressed, so that an electricity storage device exhibiting good charging and discharging characteristics can be obtained.
• the surface acid content of the polymer (A) can be measured by the method described in Examples below.
• the method for producing the polymer (A) is not particularly limited, but any method such as a solution polymerization method, a suspension polymerization method, a bulk polymerization method, an emulsion polymerization method, etc. can be used.
• a solution polymerization method a solution polymerization method
• a suspension polymerization method a suspension polymerization method
• a bulk polymerization method a bulk polymerization method
• an emulsion polymerization method etc.
• any reaction such as ionic polymerization, radical polymerization, living radical polymerization, etc. can be used.
• polymerization initiator used in polymerization examples include lauroyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, tert-butyl peroxypivalate, and 3,3,5-trimethylhexanoyl peroxide.
• organic peroxides such as; azo compounds such as ⁇ , ⁇ '-azobisisobutyronitrile; ammonium persulfate, potassium persulfate, and the like.
• emulsion polymerization methods carried out in the presence of known emulsifiers, chain transfer agents, polymerization initiators, etc. are preferred.
• emulsifiers used in the emulsion polymerization method include higher alcohol sulfate ester salts, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyldiphenyl ether disulfonates, aliphatic sulfonates, aliphatic carboxylates, dehydroabietates, Anionic surfactants such as naphthalene sulfonic acid/formalin condensates, sulfate ester salts of nonionic surfactants; nonionic surfactants such as alkyl esters of polyethylene glycol, alkylphenyl ethers of polyethylene glycol, alkyl ethers of polyethylene glycol, etc.
• fluorine-based surfactants such as perfluorobutyl sulfonate, perfluoroalkyl group-containing phosphate ester, perfluoroalkyl group-containing carboxylate, perfluoroalkyl ethylene oxide adduct;
• fluorine-based surfactants such as perfluorobutyl sulfonate, perfluoroalkyl group-containing phosphate ester, perfluoroalkyl group-containing carboxylate, perfluoroalkyl ethylene oxide adduct.
• chain transfer agent and polymerization initiator used in the emulsion polymerization method compounds described in Japanese Patent No. 5999399 and the like can be used.
• the emulsion polymerization method for synthesizing the polymer (A) may be carried out by one-stage polymerization, or may be carried out by multi-stage polymerization of two or more stages.
• the mixture of the above monomers is preferably reacted at 40 to 80°C in the presence of a suitable emulsifier, chain transfer agent, polymerization initiator, etc. It can be carried out by emulsion polymerization for 4 to 36 hours.
• each stage of polymerization is preferably set as follows.
• the proportion of monomers used in the first stage polymerization is determined by 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 20 to 99% by mass, and more preferably in the range of 25 to 99% by mass.
• the types of monomers used in the second-stage polymerization and their usage ratios may be the same as or different from the monomer types and their usage ratios used in the first-stage polymerization.
• the polymerization conditions at each stage are preferably as follows from the viewpoint of dispersibility of particles of the resulting polymer (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 a temperature of 40 to 80°C; preferably a polymerization time of 2 to 18 hours.
• This total solid content concentration is preferably 48% by mass or less, more preferably 45% by mass or less.
• a neutralizing agent is added to the polymerization mixture after the emulsion polymerization is completed to adjust the pH to 4. It is preferable to adjust it to about 5 to 10.5, preferably 5 to 10, more preferably 5.5 to 9.5.
• the neutralizing agent used here is not particularly limited, but includes, for example, metal hydroxides such as sodium hydroxide and potassium hydroxide; ammonia, and the like.
• the content ratio of polymer (A) in the binder composition for an electricity storage device according to the present embodiment is preferably 10 to 100% by mass based on 100% by mass of the polymer component, and more preferably It is preferably 20 to 95% by weight, particularly preferably 25 to 90% by weight.
• the polymer component includes, in addition to the polymer (A), a polymer other than the polymer (A) described below, a thickener, and the like.
• the binder composition for an electricity storage device 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, and one or more selected from these may be used. Can be done.
• the binder composition for an electricity storage device according to the present embodiment has a lower degree of negative impact on the environment and is highly safe for handling workers.
• the content ratio of the non-aqueous medium contained in the aqueous medium is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably not substantially contained. preferable.
• “not substantially containing” means that no non-aqueous medium is intentionally added as a liquid medium, and non-aqueous media that are inevitably mixed in when preparing a binder composition for power storage devices. It may also contain a medium.
• the binder composition for a power storage device according to the present embodiment may contain additives other than the above-mentioned components as necessary.
• additives include polymers other than polymer (A), preservatives, thickeners, and the like.
• the binder composition for a power storage device may contain a polymer other than polymer (A).
• a polymer other than polymer (A) examples include, but are not particularly limited to, acrylic polymers containing unsaturated carboxylic acid esters or derivatives thereof as constituent units, fluorine polymers such as PVDF (polyvinylidene fluoride), and the like. These polymers may be used alone or in combination of two or more. By containing these polymers, flexibility and adhesion may be further improved.
• the binder composition for a power storage device may contain a preservative.
• a preservative By containing a preservative, when the binder composition for an electricity storage device is stored, it may be possible to suppress the growth of bacteria, mold, etc. and the generation of foreign substances.
• preservatives include compounds described in Japanese Patent No. 5477610 and the like.
• the binder composition for an electricity storage device according to this embodiment may contain a thickener. By containing a thickener, it may be possible to further improve the coating properties of the slurry and the charge/discharge characteristics of the resulting electricity storage device.
• thickeners include cellulose compounds such as carboxymethyl cellulose, methyl cellulose, and hydroxypropyl cellulose; polysaccharides such as alginic acid; poly(meth)acrylic acid; ammonium salts of the cellulose compounds or poly(meth)acrylic acids. or alkali metal salts; polyvinyl alcohol-based (co)polymers such as polyvinyl alcohol, modified polyvinyl alcohol, and ethylene-vinyl alcohol copolymers; unsaturated carboxylic acids and vinyl esters such as (meth)acrylic acid, maleic acid, and fumaric acid. Water-soluble polymers such as saponified copolymers with Among these, alkali metal salts of carboxymethylcellulose, alkali metal salts of poly(meth)acrylic acid, and the like are preferred.
• Examples of commercially available thickeners include alkali metal salts of carboxymethyl cellulose such as CMC1120, CMC1150, CMC2200, CMC2280, and CMC2450 (all manufactured by Daicel Corporation).
• the binder composition for an electricity storage device contains a thickener
• the content of the thickener is 5% by mass or less with respect to 100% by mass of the total solid content of the binder composition for an electricity storage device.
• the amount is preferably 0.1 to 3% by mass, and more preferably 0.1 to 3% by mass.
• pH of binder composition for electricity storage device The pH of the binder composition for a power storage device according to the present embodiment is preferably 4.5 to 10.5, more preferably 5 to 10, particularly preferably 5.5 to 9.5.
• the pH is within the above range, it is possible to suppress the occurrence of problems such as insufficient leveling properties and liquid dripping, and it becomes easy to manufacture electricity storage device electrodes that have both good electrical properties and adhesion. .
• pH in this specification refers to a physical property measured as follows. This is a value measured in accordance with JIS Z8802:2011 at 25° C. using a pH meter using a glass electrode calibrated with a neutral phosphate standard solution and a borate standard solution as pH standard solutions. Examples of such a pH meter include “HM-7J” manufactured by DKK Toa Co., Ltd. and “D-51” manufactured by Horiba Ltd., for example.
• the pH of the binder composition for an electricity storage device is influenced by the monomer composition constituting the polymer (A), it is not determined only by the monomer composition. In other words, it is generally known that even if the monomer composition is the same, the pH of the binder composition for power storage devices changes depending on the polymerization conditions, etc., and the examples in this specification are just one example of this. Not too much.
• the monomer composition is the same, there are cases in which all unsaturated carboxylic acids are added to the polymerization reaction solution from the beginning, and then other monomers are added sequentially, and monomers other than unsaturated carboxylic acids are added in sequence.
• the amount of carboxy groups derived from the unsaturated carboxylic acid exposed on the surface of the resulting polymer differs depending on the case where the unsaturated carboxylic acid is added to the polymerization reaction solution and the unsaturated carboxylic acid is added at the end. It is thought that simply changing the order in which monomers are added in the polymerization method can greatly change the pH of the binder composition for power storage devices.
• a slurry for power storage devices contains the above-described binder composition for power storage devices.
• the binder composition for power storage devices described above can also be used as a material for producing a protective film to suppress short circuits caused by dendrites that occur during charging and discharging, and can also be used as a material for producing a protective film for suppressing short circuits caused by dendrites that occur during charging and discharging. It can also be used as a material for producing a power storage device electrode (active material layer) with improved adhesion ability between the active material and current collector and resistance to powder falling off.
• a slurry for power storage devices (hereinafter also referred to as “slurry for protective film”) for producing a protective film and a slurry for power storage devices (hereinafter also referred to as “slurry for power storage devices”) for producing the active material layer of the electrode of a power storage device are available. (Also referred to as “electrode slurry.”)
• Slurry for protective film is used to create a protective film on the surface of electrodes and separators, or both, by applying this to the surface of electrodes and/or separators, and then drying it. Refers to a dispersion liquid.
• the slurry for a protective film according to the present embodiment may be composed only of the binder composition for an electricity storage device described above, and may further contain an inorganic filler. Examples of the inorganic filler include inorganic fillers described in JP-A-2020-184461.
• Slurry for power storage device electrodes is a dispersion liquid used to create 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. Say something.
• the slurry for a power storage device electrode according to the present embodiment contains the above-described binder composition for a power storage device and an active material.
• components that can be included in the slurry for an electricity storage device electrode according to this embodiment will be explained.
• Polymer (A) The composition, physical properties, manufacturing method, etc. of the polymer (A) are as described above, and therefore their explanations will be omitted.
• the content ratio of the polymer component in the slurry for the electricity storage device electrode according to the present embodiment is preferably 1 to 8 parts by mass, more preferably 1 to 7 parts by mass, and particularly Preferably it is 1.5 to 6 parts by mass.
• the polymer component includes the polymer (A), a polymer other than the polymer (A) that is added as necessary, a thickener, and the like.
• the active material used in the slurry for the electricity storage device electrode according to this embodiment includes a positive electrode active material and a negative electrode active material. Specific examples of these include carbon materials, silicon materials, oxides containing lithium atoms, sulfur compounds, lead compounds, tin compounds, arsenic compounds, antimony compounds, aluminum compounds, conductive polymers such as polyacene, A Y O Z (However, 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, O is an oxygen atom, and X, Y, and Z are 1.10>X>0.05, 4.00>Y>0.85, 5.00>Z>1.5, respectively.)
• Composite metal oxides and other Examples include metal oxides. Specific examples of these include compounds described in Japanese Patent No. 5999399 and the like.
• the slurry for an electricity storage device electrode according to the present embodiment can be used when producing either a positive electrode or a negative electrode for an electricity storage device, it is particularly preferably used for a positive electrode.
• the lithium ion secondary battery electrode produced using the slurry for electricity storage device electrodes according to the present embodiment can exhibit good electrical characteristics even when an oxide containing lithium atoms is used as the positive electrode active material.
• the reason for this is that the polymer (A) can strongly bind oxides containing lithium atoms, and at the same time maintain the state in which oxides containing lithium atoms are firmly bound even during charging and discharging. It is believed that there is.
• the lithium atom-containing oxide is, for example, one selected from lithium atom-containing oxides (olivine-type lithium-containing phosphoric acid compounds) that are represented by the following general formula (1) and have an olivine-type crystal structure. The above can be mentioned.
• M is at least selected from the group consisting of Mg, Ti, V, Nb, Ta, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Ga, Ge, and Sn. It is an ion of one kind of metal, A is at least one kind selected from the group consisting of Si, S, P, and V, and x is a number satisfying the relationship 0 ⁇ x ⁇ 1.
• x is a number satisfying the relationship 0 ⁇ x ⁇ 1.
• olivine-type lithium-containing phosphate compounds examples include LiFePO 4 , LiCoPO 4 , LiMnPO 4 , Li 0.90 Ti 0.05 Nb 0.05 Fe 0.30 Co 0.30 Mn 0.30 PO 4 and the like. .
• LiFePO 4 lithium iron phosphate
• LiFePO 4 is particularly preferred because the iron compound as a raw material is easily available and is inexpensive.
• the average particle diameter of the olivine-type lithium-containing phosphoric acid compound is preferably in the range of 1 to 30 ⁇ m, more preferably in the range of 1 to 25 ⁇ m, and particularly preferably in the range of 1 to 20 ⁇ m.
• the active material layer may contain active materials exemplified below.
• a conductive polymer such as polyacene ;
• A 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, and 5.00>Z>1.5, respectively.
• Examples include composite metal oxides represented by and other metal oxides.
• Examples of the composite metal oxide include lithium cobalt oxide, lithium nickel oxide, lithium manganate, ternary nickel cobalt lithium manganate, and the like.
• a power storage device electrode produced using the slurry for a power storage device electrode according to the present embodiment can exhibit good electrical characteristics even when an oxide containing a lithium atom is used as the positive electrode active material.
• the reason for this is that the polymer (A) can strongly bind oxides containing lithium atoms, and at the same time maintain the state in which oxides containing lithium atoms are firmly bound even during charging and discharging. It is believed that there is.
• a mixture of a silicon material and a carbon material is preferred among the active materials listed above.
• Carbon materials have a smaller volume change due to charging and discharging than silicon materials, so by using a mixture of silicon materials and carbon materials as the negative electrode active material, the effect of volume changes of the silicon materials can be alleviated, and the active material The adhesion ability between the layer and the current collector can be further improved.
• a liquid medium may be further added to the slurry for power storage device electrodes according to the present embodiment.
• the liquid medium to be added may be the same type as or different from the liquid medium (B) contained in the binder composition for an electricity storage device, but the liquid medium (B) mentioned above It is preferable to use a liquid medium selected from among the liquid media exemplified in the section.
• the content ratio of the liquid medium (including the amount brought in from the binder composition for an electricity storage device) in the slurry for an electricity storage device electrode according to the present embodiment is the solid content concentration in the slurry (the total of components other than the liquid medium in the slurry). It is preferable that the ratio of the mass to the total mass of the slurry (the same applies hereinafter) is 30 to 70% by mass, and more preferably 40 to 60% by mass.
• a conductive additive may be further added to the slurry for an electricity storage device electrode according to the present embodiment for the purpose of imparting conductivity and buffering changes in volume of the active material due to inflow and outflow of lithium ions.
• the conductive aid include carbon such as activated carbon, acetylene black, Ketjen black, furnace black, graphite, carbon fiber, fullerene, and carbon nanotubes.
• carbon such as activated carbon
• acetylene black or carbon nanotubes can be preferably used.
• the content of the conductivity imparting agent is preferably 20 parts by mass or less, more preferably 1 to 15 parts by mass, particularly preferably 2 to 10 parts by mass, based on 100 parts by mass of the active material.
• a pH adjuster and/or a corrosion inhibitor may be further added to the slurry for a power storage device electrode according to the present embodiment for the purpose of suppressing corrosion of the current collector.
• pH adjusting agent examples include hydrochloric acid, phosphoric acid, sulfuric acid, acetic acid, formic acid, ammonium phosphate, ammonium sulfate, ammonium acetate, ammonium formate, ammonium chloride, sodium hydroxide, potassium hydroxide, etc.
• sulfuric acid, ammonium sulfate, sodium hydroxide, and potassium hydroxide are preferred.
• Corrosion inhibitors include ammonium metavanadate, sodium metavanadate, potassium metavanadate, ammonium metatungstate, sodium metatungstate, potassium metatungstate, ammonium paratungstate, sodium paratungstate, potassium paratungstate, molybdic acid. Ammonium, sodium molybdate, potassium molybdate, etc. can be mentioned. Among these, ammonium paratungstate, ammonium metavanadate, sodium metavanadate, potassium metavanadate, and ammonium molybdate are preferred.
• Cellulose fibers may be further added to the slurry for the electricity storage device electrode according to this embodiment.
• the adhesion of the active material to the current collector may be improved. It is thought that by fibrous cellulose fibers binding adjacent active materials to each other through line adhesion or line contact, it is possible to prevent the active materials from falling off and to improve the adhesion to the current collector.
• the slurry for electricity storage device electrodes according to the present embodiment can be manufactured by any method as long as it contains the above-mentioned binder composition for electricity storage devices and active material. You can. From the viewpoint of producing a slurry with better dispersibility and stability more efficiently and at a lower cost, active materials and optional additive components used as necessary are added to the above-mentioned binder composition for power storage devices. It is preferable to manufacture by mixing.
• a specific manufacturing method includes, for example, the method described in Japanese Patent No. 5999399.
• the electricity storage device electrode according to one embodiment of the present invention includes a current collector and an active material layer formed by applying and drying the above slurry for an electricity storage device electrode on the surface of the current collector. It is something to be prepared for.
• Such electricity storage device electrodes are produced by applying the above slurry for electricity storage device electrodes to the surface of a current collector such as metal foil to form a coating film, and then drying the coating film to form an active material layer. can be manufactured.
• an active material layer containing the above-mentioned polymer (A), an active material, and optional components added as necessary is bound to the surface of the current collector. Since the material is made of aluminum, it has excellent adhesion and flexibility, reduces the increase in internal resistance, and provides a power storage device with excellent cycle characteristics.
• the current collector is not particularly limited as long as it is made of a conductive material, and examples include the current collector described in Japanese Patent No. 5999399.
• the electricity storage device includes the above-mentioned electricity storage device electrode, further contains an electrolytic solution, and can be manufactured according to a conventional method using parts such as a separator.
• a specific manufacturing method includes, for example, stacking a negative electrode and a positive electrode with a separator in between, rolling or folding them according to the shape of the battery, storing them in a battery container, and injecting an electrolyte into the battery container.
• An example of this is a method of sealing the container.
• the shape of the battery can be any appropriate shape, such as a coin shape, a cylindrical shape, a square shape, or a laminate shape.
• the electrolytic solution may be liquid or gel-like, and depending on the type of active material, an electrolytic solution that effectively functions as a battery may be selected from known electrolytic solutions used in power storage devices.
• the electrolytic solution can be a solution in which an electrolyte is dissolved in a suitable solvent. Examples of such electrolytes and solvents include compounds described in Japanese Patent No. 5999399 and the like.
• the above-described power storage device is applicable to lithium ion secondary batteries, electric double layer capacitors, lithium ion capacitors, etc. that require discharge at a large current density.
• lithium ion secondary batteries are particularly preferred.
• members other than the binder composition for electricity storage devices may be known members for lithium ion secondary batteries, electric double layer capacitors, and lithium ion capacitors. It is.
• Example 1 5.1.1. Preparation of binder composition for power storage device A separable flask with a capacity of 7 liters was charged with 90 parts by mass of water and 0.2 parts by mass of sodium dodecylbenzenesulfonate, and 15 parts by mass of n-butyl acrylate (BA) as a monomer. 1 part by mass of allyl methacrylate (AMA) and 5 parts by mass of styrene (ST) were sufficiently stirred to prepare a monomer emulsion containing a mixture of the above monomers.
• BA n-butyl acrylate
• AMA allyl methacrylate
• ST styrene
• the temperature inside the separable flask was started to rise, and when the internal temperature reached 60° C., 0.5 parts by mass of ammonium persulfate was added as a polymerization initiator. Thereafter, the temperature of the separable flask was raised to 70°C, and polymerization was carried out for 6 hours. After confirming that the conversion rate exceeded 80%, 60 parts by mass of water and 0.3 parts by mass of sodium dodecylbenzenesulfonate were charged, and 1 part by mass of allyl methacrylate (AMA) and styrene (ST) were added as monomers.
• AMA allyl methacrylate
• ST styrene
• a monomer emulsion containing a well-stirred mixture of the above monomers containing 68 parts by mass, 5 parts by mass of acrylic acid (AA), and 5 parts by mass of acrylonitrile (AN) was slowly added over 3 hours. Thereafter, the temperature inside the separable flask was raised to 85° C., and this temperature was maintained for 3 hours to carry out a polymerization reaction. After 3 hours, the separable flask was cooled to stop the reaction, and then an aqueous sodium hydroxide solution was added to adjust the pH to 8.0, thereby producing water containing 40% by mass of particles made of polymer (A). A dispersion was obtained.
• a film of polymer (A) was used as a measurement sample in dynamic viscoelasticity measurement.
• the polymer (A) film was prepared by drying the polymer (A) at 40°C for 24 hours to produce a uniform film with a thickness of 1.0 ⁇ 0.3mm, and drying this film at 160°C in a vacuum dryer. After drying for 30 minutes, it was cut into strips of 10 mm x 10 mm.
• the measurement sample was fixed on a parallel plate (product name "PP-12"), and the measurement was performed in the temperature range of -70°C to 180°C under the following measurement conditions.
• Electrolyte swelling rate (mass%) (Z/(1-Y)) x 100 (2)
• the surface acid content of the particles of polymer (A) obtained above was measured as follows. First, confirm that 0.005 mol/L of sulfuric acid is filled in the titration buret and reagent bottle on the top of the titration buret of the potentiometric titration device (manufactured by Kyoto Electronics Industry Co., Ltd., model "AT-510"). It was confirmed that the conductivity of water was 2 ⁇ S or less. Next, purging was performed to remove air from within the burette, and further bubbles were removed from the nozzle.
• Amount of surface acid (mmol/g) Amount of acid used in the carboxylic acid area on the particle surface [mL] x Concentration of acid [mol/L] x Degree of ionization/Sample weight [g]/1000 (3 )
• a slurry for a non-aqueous secondary battery positive electrode was prepared by stirring and mixing at 1800 rpm for 1.5 minutes under vacuum (approximately 5.0 ⁇ 10 3 Pa) for 5 minutes.
• positive electrode for non-aqueous secondary battery 5.1.4.1. Preparation of positive electrode for non-aqueous secondary batteries
• the slurry for positive electrodes for non-aqueous secondary batteries obtained above was applied to the surface of a current collector made of aluminum foil with a thickness of 20 ⁇ m so that the film thickness after drying was 100 ⁇ m. It was applied uniformly by a doctor blade method and dried at 120° C. for 20 minutes. Thereafter, a positive electrode for a non-aqueous secondary battery was obtained by pressing using a roll press machine so that the density of the formed film (positive electrode active material layer) was 3.0 g/cm 3 .
• the positive electrode for a non-aqueous secondary battery obtained above was punched out into a shape of 4 cm x 6 cm.
• the punched electrodes were vacuum dried at 160° C. for 6 hours. Thereafter, the electrode was evaluated by visually checking for cracks in the electrode when bent by 180° in a dry room using a cylindrical mandrel method using a 0.514-Type 1 paint film bending tester manufactured by Yasuda Seiki.
• the mandrel diameters used were ⁇ 4, ⁇ 5, ⁇ 6, ⁇ 8, ⁇ 10, ⁇ 12, ⁇ 16, ⁇ 20, ⁇ 25, and ⁇ 32 mm.
• the evaluation criteria are as follows. The evaluation results are shown in Table 1.
• SBR trade name "TRD105A", manufactured by ENEOS Materials Co., Ltd.
• SBR trade name "TRD105A”
• ENEOS Materials Co., Ltd. was added in an amount equivalent to 2 parts by mass (in terms of solid content), and the mixture was further stirred for 1 hour to obtain a paste.
• a slurry for a non-aqueous secondary battery negative electrode was prepared by stirring and mixing for 5 minutes at 1,800 rpm under vacuum for 1.5 minutes.
• the slurry for a non-aqueous secondary battery negative electrode prepared above was uniformly applied to the surface of a current collector made of copper foil with a thickness of 20 ⁇ m using a doctor blade method so that the film thickness after drying was 80 ⁇ m. and dried at 120°C for 20 minutes. Thereafter, a negative electrode for a non-aqueous secondary battery was obtained by pressing using a roll press machine so that the density of the formed film (negative electrode active material layer) was 1.9 g/cm 3 .
• a separator made of a polypropylene porous membrane punched into a circular shape with a diameter of 24 mm (manufactured by Celgard Co., Ltd., trade name "Celgard #2400") was placed on top of the negative electrode for a non-aqueous secondary battery.
• the positive electrode for non-aqueous secondary batteries produced above was punched into a circular shape with a diameter of 15.95 mm and placed on top of the separator.
• a lithium ion battery cell (an example of a non-aqueous secondary battery) was assembled by closing and sealing the exterior body of the bipolar coin cell with screws.
• Capacity retention rate (%) (discharge capacity at 100th cycle/discharge capacity at 1st cycle) x 100 (4) (Evaluation criteria)
• ⁇ 5 points Capacity retention rate is 95% or more.
• ⁇ 4 points Capacity retention rate is 90% or more and less than 95%.
• ⁇ 3 points Capacity retention rate is 85% or more and less than 90%.
• ⁇ 2 points Capacity retention rate is 80% or more and less than 85%.
• ⁇ 1 point Capacity retention rate is 75% or more and less than 80%.
• the time point was defined as the completion of charging (cutoff). Thereafter, discharging was started at a constant current (1.0 C), and the time when the voltage reached 3.0 V was defined as the completion of discharging (cutoff), and the discharge capacity of the first cycle was calculated. Charging and discharging was repeated 100 times in this manner. After repeating charging and discharging 100 times, charging and discharging were performed in the same manner as in the 0th cycle, and the 101st discharge capacity was evaluated. The rate of increase in resistance was calculated using the following formula (5), and evaluated using the following criteria.
• Resistance increase rate (%) (Discharge capacity at 101st cycle - Discharge capacity at 100th cycle) / (Discharge capacity at 0th cycle - Discharge capacity at 1st cycle) x 100 (5) (Evaluation criteria) - 5 points: resistance increase rate is 100% or more and less than 110%.
• ⁇ 4 points Resistance increase rate is 110% or more and less than 120%.
• ⁇ 3 points Resistance increase rate is 120% or more and less than 130%.
• ⁇ 2 points Resistance increase rate is 130% or more and less than 140%.
• - 1 point resistance increase rate is 140% or more and less than 150%.
• ⁇ 0 point resistance increase rate is 150% or more.
• 1C refers to a current value at which a cell having a certain capacitance is discharged at a constant current and the discharge ends in one hour.
• 0.1C refers to a current value that takes 10 hours to finish discharging
• 10C refers to a current value that takes 0.1 hour to finish discharging.
• Evaluation Results Tables 1 to 4 show the composition of the binder composition for power storage devices, the evaluation of the physical properties of the polymer, and the results of the evaluation of the characteristics of the power storage device electrodes and power storage devices.
• each monomer in Table 1 and Table 2 represents the following monomer, respectively.
• Tp2 of the polymer (A) is between 50°C and 150°C, fusion between particles is suppressed and coverage of the active material is suppressed, making it easy to insert and remove lithium ions. Therefore, the permeability of the electrolytic solution between the active materials is not inhibited and the resistance can be low. It is presumed that as a result of showing good adhesion strength, flexibility, and low resistance, it showed good charge/discharge characteristics.
• the active materials can be more suitably bound together. It can be seen that it is possible to maintain good adhesion between the active material layer and the current collector.
• the non-aqueous secondary battery positive electrode slurry shown in Example 13 can suitably bind active materials to each other even when alginic acid is used as a thickener, and the active material layer and current collector It can be seen that good adhesion can be maintained.
• the non-aqueous secondary battery negative electrode slurry according to the present invention shown in Example 18 showed good results even when a negative electrode active material was used. It is considered that the improved electrolyte affinity facilitated the insertion and removal of Li ions into the negative electrode active material, resulting in lower resistance, which resulted in good charge-discharge characteristics.
• the present invention is not limited to the above-described embodiments, and various modifications are possible.
• the present invention includes configurations that are substantially the same as those described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objectives and effects).
• the present invention includes configurations in which non-essential parts of the configurations described in the above embodiments are replaced with other configurations.
• the present invention also includes configurations that have the same effects or can achieve the same objectives as the configurations described in the above embodiments.
• the present invention also includes a configuration in which known technology is added to the configuration described in the above embodiments.

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• 2023
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