WO2015108109A1 - Binder for electrode of non-aqueous electrolyte secondary cell, electrode for non-aqueous secondary cell containing said binder, and non-aqueous electrolyte secondary cell provided with said electrode - Google Patents

Binder for electrode of non-aqueous electrolyte secondary cell, electrode for non-aqueous secondary cell containing said binder, and non-aqueous electrolyte secondary cell provided with said electrode Download PDF

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Publication number
WO2015108109A1
WO2015108109A1 PCT/JP2015/050946 JP2015050946W WO2015108109A1 WO 2015108109 A1 WO2015108109 A1 WO 2015108109A1 JP 2015050946 W JP2015050946 W JP 2015050946W WO 2015108109 A1 WO2015108109 A1 WO 2015108109A1
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Prior art keywords
binder
electrode
electrolyte secondary
active material
secondary battery
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PCT/JP2015/050946
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French (fr)
Japanese (ja)
Inventor
祐治 金原
隼一 藤重
信貴 藤本
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住友精化株式会社
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Publication of WO2015108109A1 publication Critical patent/WO2015108109A1/en

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    • 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
    • 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
    • C08F220/1818—C13or longer chain (meth)acrylate, e.g. stearyl (meth)acrylate
    • 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
    • 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
    • C08F220/04—Acids; Metal salts or ammonium salts thereof
    • C08F220/06—Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/02—Homopolymers or copolymers of acids; Metal or ammonium salts thereof
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives 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; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C09J133/06—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
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J4/00—Adhesives based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; adhesives, based on monomers of macromolecular compounds of groups C09J183/00 - C09J183/16
    • 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
    • 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 is a non-aqueous electrolyte that can effectively suppress the peeling of an electrode mixture and the detachment of an active material from a current collector, and has excellent binding durability even when charging and discharging are repeated. It is related with the binder for electrodes of a secondary battery, the electrode for nonaqueous electrolyte secondary batteries containing the said binder, and a nonaqueous electrolyte secondary battery provided with the said electrode.
  • the electrode of the non-aqueous electrolyte secondary battery is generally composed of an active material and a binder solution in which a binder for an electrode (hereinafter sometimes simply referred to as a binder) is dissolved in a solvent, or a dispersion in which a dispersion medium is dispersed.
  • a binder for an electrode hereinafter sometimes simply referred to as a binder
  • An electrode mixture slurry mixed with a conductive additive hereinafter sometimes simply referred to as a slurry
  • the solvent or dispersion medium is removed by a method such as drying to obtain an active material, a conductive additive, and It is manufactured by binding the current collectors.
  • the positive electrode of a non-aqueous electrolyte secondary battery is generally obtained by dispersing lithium cobaltate (LiCoO 2 ) as a positive electrode active material, polyvinylidene fluoride (PVdF) as a binder, and carbon black as a conductive additive in a dispersion medium. It is obtained by coating and drying a slurry of the positive electrode mixture on an aluminum foil current collector.
  • LiCoO 2 lithium cobaltate
  • PVdF polyvinylidene fluoride
  • the negative electrode generally includes graphite as a negative electrode active material, carboxymethyl cellulose (CMC), styrene butadiene rubber (SBR), PVdF or polyimide as a binder, and carbon black as a conductive additive in a dispersion medium.
  • CMC carboxymethyl cellulose
  • SBR styrene butadiene rubber
  • PVdF polyimide
  • carbon black as a conductive additive in a dispersion medium. This slurry is obtained by coating and drying on a copper foil current collector.
  • binders are important determinants of characteristics such as battery capacity, charge / discharge cycle characteristics, and rate characteristics.
  • characteristics such as battery capacity, charge / discharge cycle characteristics, and rate characteristics.
  • the binder cannot bind a sufficient amount of the active material to the current collector or when the binder cannot bind the active materials, a battery having a large capacity cannot be obtained.
  • the binding force of the binder is reduced due to a change in the volume of the active material due to repeated charge and discharge, the active material is dropped from the current collector and the capacity of the battery is reduced.
  • the binder covers the active material and conceals the surface, the battery reaction is hindered, and the battery capacity, charge / discharge cycle characteristics, and rate characteristics deteriorate.
  • the binder is required to have a strong binding property between the active material and the current collector and between the active materials, and to maintain the binding property so that the active material does not fall off the current collector even after repeated charge and discharge.
  • it is required to expose the surface of the active material by covering the active material with lines or dots without covering the active material with a surface.
  • PVdF Polyvinylidene fluoride
  • Patent Documents 1 and 2 PVdF is dissolved in N-methylpyrrolidone or the like to form a binder composition for an electrode, and then an active material is mixed to form a slurry, which is applied to a current collector and dried. A secondary battery electrode is formed.
  • PVdF which is a fluorine-based polymer, has the advantage of low concealment with respect to the active material, but lacks binding power and flexibility. For this reason, it is necessary to use a binder in large quantities, and there is a problem that the binder conceals the active material. Moreover, since the binder is used in a large amount, there is a problem that the ratio of the active material in the electrode is reduced. Furthermore, PVdF also has a problem that the life characteristics and high-rate discharge characteristics of the electrode deteriorate.
  • Patent Documents 3 and 4 there is a method in which latex, which is a rubbery polymer, is used for the binder composition in order not to reduce the binding force even by the volume fluctuation of the active material due to repeated charge and discharge. It is disclosed.
  • this method there is a problem that, when an electrode coated on a current collector such as aluminum or copper is pressed, consolidation is inhibited due to rubber elasticity. Further, since the viscosity of the latex of the rubbery polymer is insufficient, the electrode slurry cannot be applied, and it is necessary to use it together with a thickener such as carboxymethyl cellulose, polyvinyl alcohol, polyacrylic acid and the like. For this reason, there is a problem that these composite binders cover and conceal the surface of the active material, thereby reducing the battery capacity, and in particular, sufficient rate characteristics cannot always be obtained.
  • a thickener such as carboxymethyl cellulose, polyvinyl alcohol, polyacrylic acid and the like.
  • the present invention has been made in view of the current state of the prior art described above, and its main purpose is to effectively suppress the peeling of the electrode mixture and the detachment of the active material from the current collector.
  • Non-aqueous electrolyte secondary battery electrode binders having excellent binding durability against repeated charge and discharge, non-aqueous electrolyte secondary battery electrodes containing the binder, and using the electrodes, the battery capacity is large
  • Another object of the present invention is to provide a nonaqueous electrolyte secondary battery having excellent charge / discharge cycle characteristics, and an electric device using the battery.
  • the present inventors diligently studied to solve the above problems.
  • the electrode binder of the non-aqueous electrolyte secondary battery made of a specific copolymer can effectively suppress the peeling of the electrode mixture and the detachment of the active material from the current collector. It has been found that it has excellent binding durability even with repeated discharge. Furthermore, it has been found that by using the binder as an electrode binder for a non-aqueous electrolyte secondary battery, a non-aqueous electrolyte secondary battery having a large battery capacity and excellent charge / discharge cycle characteristics can be obtained.
  • the present invention is an invention which has been completed based on such findings and further earnest studies.
  • Electrode of non-aqueous electrolyte secondary battery comprising an alkyl-modified carboxyl group-containing copolymer obtained by copolymerizing (meth) acrylic acid and (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms Binder.
  • the term (meth) acrylic acid alkyl ester having 18 to 24 carbon atoms in the alkyl group is copolymerized at a ratio of 0.1 to 10 parts by mass with respect to 100 parts by mass of the (meth) acrylic acid.
  • the binder for electrodes of the nonaqueous electrolyte secondary battery according to 1.
  • nonaqueous electrolyte according to Item 1 or 2 wherein the compound having two or more ethylenically unsaturated groups is copolymerized at a ratio of 0.5 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic acid.
  • Secondary battery electrode binder Item 4.
  • Item 4. The compound according to Item 3, wherein the compound having two or more ethylenically unsaturated groups is at least one selected from the group consisting of pentaerythritol allyl ether, diethylene glycol diallyl ether, polyethylene glycol diallyl ether, and polyallyl saccharose. Binder for electrodes of non-aqueous electrolyte secondary batteries. Item 5.
  • An electrode for a non-aqueous electrolyte secondary battery comprising an active material, a conductive additive, and a binder for an electrode of the non-aqueous electrolyte secondary battery according to any one of Items 1 to 4.
  • Item 6. A nonaqueous electrolyte secondary battery comprising the electrode for a nonaqueous electrolyte secondary battery according to Item 5.
  • Item 7. An electric device comprising the nonaqueous electrolyte secondary battery according to item 6.
  • an alkyl-modified carboxyl group-containing copolymer obtained by copolymerizing (meth) acrylic acid and a (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms Use as a binder.
  • the manufacturing method of the electrode for nonaqueous electrolyte secondary batteries provided with the process of apply
  • the binder for an electrode of the nonaqueous electrolyte secondary battery of the present invention is an alkyl-modified carboxyl group obtained by copolymerizing (meth) acrylic acid and a (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms. It is possible to effectively suppress the separation of the electrode mixture containing the copolymer, the active material, and the conductive additive from the current collector and the detachment of the active material. It has excellent binding durability even when repeated. Therefore, by using the binder of the present invention for the electrode, a nonaqueous electrolyte secondary battery having a large battery capacity and excellent charge / discharge cycle characteristics (battery life characteristics) can be obtained.
  • the binder for an electrode of the nonaqueous electrolyte secondary battery of the present invention is an alkyl-modified carboxyl group obtained by copolymerizing (meth) acrylic acid and a (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms. It consists of a containing copolymer.
  • the binder of the present invention electrodes for a non-aqueous electrolyte secondary battery (a positive electrode and a negative electrode) containing the binder, a non-aqueous electrolyte secondary battery using the electrode, and an electric device using the battery will be described in detail. .
  • the binder for an electrode of the nonaqueous electrolyte secondary battery of the present invention is an alkyl-modified carboxyl group obtained by copolymerizing (meth) acrylic acid and a (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms. Containing copolymer.
  • (meth) acrylic acid is a general term for “acrylic acid and methacrylic acid”, and the same applies to those similar to this.
  • examples of (meth) acrylic acid include acrylic acid, ⁇ -methylacrylic acid, and methacrylic acid, and acrylic acid and methacrylic acid are preferably used.
  • (Meth) acrylic acid may be used alone or in combination of two or more.
  • the (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms refers to an ester of (meth) acrylic acid and a higher alcohol having an alkyl group having 18 to 24 carbon atoms.
  • Examples include stearyl acrylate, eicosanyl acrylate, behenyl acrylate, tetracosanyl acrylate, stearyl methacrylate, eicosanyl methacrylate, behenyl methacrylate, tetracosanyl methacrylate, and the like.
  • stearyl (meth) acrylate and (meth) acrylic are inexpensive and easily available, and from the viewpoint of excellent coatability of the binder made of the resulting copolymer, and from the viewpoint of binding strength.
  • Acid eicosanyl, behenyl (meth) acrylate, and tetracosanyl (meth) acrylate are preferably used.
  • the (meth) acrylic acid alkyl ester having 18 to 24 carbon atoms in the alkyl group for example, a commercially available product such as “Blemmer VMA70” manufactured by NOF Corporation may be used.
  • the (meth) acrylic acid alkyl ester having 18 to 24 carbon atoms in the alkyl group may be used alone or in combination of two or more.
  • the combination of (meth) acrylic acid constituting the alkyl-modified carboxyl group-containing copolymer and the (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms is independent of each other. They may be combined, or one or both may be used in combination of two or more.
  • the proportion of the alkyl group (meth) acrylic acid alkyl ester having 18 to 24 carbon atoms in the alkyl group is not particularly limited, but for the electrode from the current collector From the viewpoint of preventing exfoliation of the mixture and detachment of the active material and imparting excellent binding durability to repeated charge and discharge, preferably 0.1 to 10 parts per 100 parts by weight of (meth) acrylic acid. About 5 parts by mass, more preferably about 0.1 to 5 parts by mass, and still more preferably about 1 to 5 parts by mass.
  • the binder of the present invention can effectively suppress the peeling of the electrode mixture from the current collector and the detachment of the active material, and has excellent binding durability against repeated charge and discharge. ing. Therefore, it is possible to realize a non-aqueous electrolyte secondary battery having a high capacity and excellent charge / discharge cycle characteristics. Details of the reason why the binder of the present invention exhibits such excellent effects are not necessarily clear, but can be considered as follows, for example. That is, in the alkyl-modified carboxyl group-containing copolymer constituting the binder of the present invention, a (meth) acrylic acid alkyl ester having a long-chain alkyl group having 18 to 24 carbon atoms is copolymerized.
  • the neutralized salt portion of (meth) acrylic acid formed by alkali neutralization of the copolymer does not firmly cover the active material due to the amorphous nature due to ion repulsion of the carboxyl group, that is, the active material and the electrolyte It is presumed that a function to improve the affinity with is expressed.
  • the binder of the present invention it is possible to effectively suppress the peeling of the electrode mixture from the current collector and the detachment of the active material, and it is excellent for repeated charge and discharge. It is thought that it has binding durability. Further, it is considered that the active material is uniformly dispersed to reduce the resistance of the electrode and improve the battery performance.
  • ethylenic A compound having two or more unsaturated groups may be copolymerized.
  • limit especially as a compound which has two or more ethylenically unsaturated groups The peeling of the electrode mixture from an electrical power collector and the detachment
  • a compound in which the ethylenically unsaturated group is an allyl group is preferable.
  • conductive assistants such as carbon fibers, and current collectors such as aluminum and copper
  • pentaerythritol diallyl ether, pentaerythritol triallyl ether, pentaerythritol tetra More preferred are pentaerythritol allyl ether such as allyl ether, diethylene glycol diallyl ether, polyethylene glycol diallyl ether, and polyallyl saccharose.
  • these compounds having two or more ethylenically unsaturated groups may be used alone or in combination of two or more.
  • the ratio in the case of using a compound having two or more ethylenically unsaturated groups is 0.5 parts by mass or less, preferably 0.001 to 0.005 parts per 100 parts by mass of (meth) acrylic acid. About 5 parts by mass, more preferably about 0.01 to 0.2 parts by mass. If the ratio of the compound which has 2 or more of ethylenically unsaturated groups is 0.5 mass part or less, the electrode mixture slurry containing a binder will become uniform and there is no possibility that battery performance may fall.
  • the weight average molecular weight of the alkyl-modified carboxyl group-containing copolymer constituting the binder of the present invention is not particularly limited, and examples thereof include about 10,000 to 10,000,000.
  • the weight average molecular weight is a value obtained by measurement by gel permeation chromatography (GPC) using standard polystyrene styrene.
  • (meth) acrylic acid a (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms, a compound having two or more ethylenically unsaturated groups used as necessary
  • the method for obtaining an alkyl-modified carboxyl group-containing copolymer by copolymerizing is not particularly limited, and these raw materials are stirred in a solvent in an inert gas atmosphere and polymerized using a polymerization initiator, etc. The usual method can be used.
  • the polymerization method is not particularly limited, and usual emulsion polymerization, suspension polymerization, dispersion polymerization, solution polymerization, precipitation polymerization and the like can be used, and preferably emulsion polymerization, suspension polymerization, dispersion polymerization, precipitation polymerization are used. be able to.
  • the inert gas include nitrogen gas and argon gas.
  • (meth) acrylic acid As a solvent used for copolymerization, (meth) acrylic acid, (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms, and ethylenically unsaturated group to be used as needed are used.
  • the compound having at least one is dissolved, but is not particularly limited as long as it does not dissolve the alkyl-modified carboxyl group-containing copolymer produced by copolymerization and does not inhibit the reaction.
  • the solvent include chain hydrocarbons such as normal pentane, normal hexane, isohexane, normal heptane, normal octane and isooctane; alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane and methylcyclohexane; benzene, Aromatic hydrocarbons such as toluene, xylene and chlorobenzene; halogenated hydrocarbons such as ethylene dichloride; esters such as ethyl acetate and isopropyl acetate; ketones such as methyl ethyl ketone and methyl isobutyl ketone.
  • a solvent may be used individually by 1 type and may be used in combination of 2 or more type.
  • the polymerization initiator used for the copolymerization is not particularly limited, but a radical polymerization initiator is preferably used.
  • ⁇ , ⁇ ′-azoisobutyronitrile, 2,2′-azobis-2,4-dimethyl is used.
  • examples include valeronitrile, 2,2′-azobismethylisobutyrate, benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, and tertiary butyl hydroperoxide.
  • 2,2'-azobismethylisobutyrate is preferable from the viewpoint of easy handling and excellent stability.
  • the amount of the polymerization initiator used is not particularly limited, but is preferably about 0.00003 to 0.002 mol per 1 mol of (meth) acrylic acid, for example.
  • the amount of the polymerization initiator used is less than 0.00003 mol, the reaction rate becomes slow, which may not be economical.
  • the usage-amount of a polymerization initiator exceeds 0.002 mol, since superposition
  • the reaction temperature is not particularly limited, but is preferably about 50 to 90 ° C, more preferably about 55 to 75 ° C.
  • the reaction temperature is less than 50 ° C., the viscosity of the reaction solution increases, and it may not be possible to stir uniformly.
  • reaction temperature exceeds 90 degreeC, reaction advances rapidly and reaction control may become impossible.
  • the reaction time varies depending on the reaction temperature and cannot be determined unconditionally, but is usually about 0.5 to 5 hours.
  • the reaction solution is heated to about 80 to 130 ° C., for example, and the solvent is distilled off to obtain an alkyl-modified carboxyl group-containing copolymer.
  • the heating temperature is less than 80 ° C., drying may take a long time.
  • heating temperature exceeds 130 degreeC, the solubility to liquid media, such as water, of the alkyl-modified carboxyl group-containing copolymer obtained may deteriorate.
  • the volume average particle size of the alkyl-modified carboxyl group-containing copolymer thus obtained is not particularly limited, but is preferably about 0.1 to 50 ⁇ m, more preferably about 0.5 to 30 ⁇ m. More preferably, it is about ⁇ 20 ⁇ m.
  • the volume average particle diameter is less than 0.1 ⁇ m, the amount of binder necessary for sufficiently binding the active material in the electrode increases, and as a result, the binder coats the surface of the active material, resulting in rate characteristics. May decrease.
  • the volume average particle diameter of the copolymer exceeds 50 ⁇ m, there is a possibility that the dispersion of the conductive auxiliary agent becomes non-uniform and resistance increases.
  • volume average particle diameter may be 100 to 1000 ⁇ m.
  • SALD-7100 laser diffraction particle size distribution analyzer
  • the binder comprising the alkyl-modified carboxyl group-containing copolymer of the present invention is used for an electrode, it is usually used by being dissolved or dispersed in a liquid medium such as water described later.
  • the binder for an electrode of the nonaqueous electrolyte secondary battery of the present invention can effectively suppress the peeling of the electrode mixture from the current collector and the detachment of the active material, and repeated charge and discharge. In addition, it has excellent binding durability. Therefore, by using the binder of the present invention for the positive electrode, a nonaqueous electrolyte secondary battery having a large battery capacity and excellent charge / discharge cycle characteristics can be obtained.
  • the positive electrode in the present invention is manufactured, for example, as follows.
  • a positive electrode active material, a conductive additive, a binder of the present invention, and a liquid medium such as water are mixed to form a paste slurry as a positive electrode mixture.
  • the positive electrode for a non-aqueous electrolyte secondary battery of the present invention can be obtained.
  • the binder of the present invention may be used by dissolving in a liquid medium in advance, or the powdered binder of the present invention and a positive electrode active material may be mixed in advance, and then the liquid medium may be added and used.
  • the well-known positive electrode active material used with a nonaqueous electrolyte secondary battery can be used.
  • Specific examples of the positive electrode active material include lithium iron phosphate (LiFePO 4 ), lithium manganese phosphate (LiMnPO 4 ), lithium cobalt phosphate (LiCoPO 4 ), iron pyrophosphate (Li 2 FeP 2 O 7 ), cobalt acid Lithium composite oxide (LiCoO 2 ), spinel type lithium manganate composite oxide (LiMn 2 O 4 ), lithium manganate composite oxide (LiMnO 2 ), lithium nickelate composite oxide (LiNiO 2 ), lithium niobate composite oxide (LiNbO 2), ferrate lithium composite oxide (LiFeO 2), lithium magnesium acid complex oxide (LiMgO 2), lithium composite oxide of calcium acid (LiCaO 2), cuprate lithium composite oxide (LiCuO 2)
  • the conductive auxiliary agent is not particularly limited as long as it has conductivity, but carbon powder is preferable.
  • carbon powder those commonly used, for example, acetylene black (AB), ketjen black (KB), graphite, carbon fiber, carbon tube, graphene, amorphous carbon, hard carbon, soft carbon, glassy carbon And carbon materials such as carbon nanofibers and carbon nanotubes.
  • a conductive support agent may be used individually by 1 type, and may be used in combination of 2 or more types.
  • carbon nanofibers and carbon nanotubes are preferable from the viewpoint of improving conductivity, and carbon nanotubes are more preferable.
  • the amount used is not particularly limited, but is preferably about 30 to 100% by mass, and more preferably about 40 to 100% by mass of the total conductive auxiliary.
  • the amount of carbon nanotube used is less than 30% by mass, a sufficient conductive path is not ensured between the positive electrode active material and the positive electrode current collector, and a sufficient conductive path may not be formed particularly in high-speed charge / discharge.
  • Carbon nanofiber refers to a fibrous material having a thickness of several nanometers to several hundred nanometers, and one having a hollow structure is particularly referred to as a carbon nanotube.
  • carbon nanotubes such as single-walled carbon nanotubes and multi-walled carbon nanotubes. These are produced by various methods such as a vapor phase growth method, an arc discharge method, and a laser evaporation method, but the production method is not particularly limited.
  • the amount of the conductive auxiliary used in the positive electrode is not particularly limited.
  • the total amount of the positive electrode active material, the conductive auxiliary, and the binder is 100% by mass, it is preferably about 1.5 to 20% by mass. Preferably, it is about 2.0 to 10% by mass.
  • the electroconductivity of a positive electrode may not fully be improved as the usage-amount of a conductive support agent is less than 1.5 mass%.
  • the amount of the conductive auxiliary agent used exceeds 20% by mass, the ratio of the positive electrode active material is relatively reduced. Therefore, it is difficult to obtain a high capacity during charge / discharge of the battery, and when water is used as the liquid medium.
  • the carbon powder of the conductive auxiliary agent repels water, causing aggregation of the positive electrode active material, and because it is small compared to the positive electrode active material, the surface area increases and the amount of binder used increases. This is not preferable.
  • the amount of the binder of the present invention used in the positive electrode is not particularly limited.
  • the total amount of the positive electrode active material, the conductive additive, and the binder is 100% by mass, preferably 0.5% by mass to 30% by mass.
  • it is 1 mass% or more and 20 mass% or less, More preferably, 2 mass% or more and 8 mass% or less are mentioned.
  • the amount of the binder is too large, the resistance in the electrode of the positive electrode may increase and the high rate discharge characteristics may be deteriorated. Moreover, when there are too few binders, a charge / discharge cycle characteristic may fall.
  • liquid medium examples include water and non-aqueous media.
  • non-aqueous media include aliphatic hydrocarbons such as n-octane, isooctane, nonane, decane, decalin, pinene, and chlorododecane; and cyclic aliphatic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane, and methylcyclopentane.
  • Aromatic hydrocarbons such as styrene, chlorobenzene, chlorotoluene, ethylbenzene, diisopropylbenzene, cumene; alcohols such as methanol, ethanol, propanol, isopropanol, butanol, benzyl alcohol, glycerin; acetone, methyl ethyl ketone, cyclopentanone, Ketones such as isophorone; ethers such as methyl ethyl ether, diethyl ether, tetrahydrofuran and dioxane; and lacquers such as ⁇ -butyrolactone and ⁇ -butyrolactone Tons; Lactams such as ⁇ -lactam; Chain and cyclic amides such as dimethylformamide, N-methylpyrrolidone and dimethylacetamide; Methylene cyanohydrin, ethylene cyanohydrin, 3,3′-thiodipro
  • Nitrile group-containing compounds nitrogen-containing heterocyclic compounds such as pyridine and pyrrole; glycols such as ethylene glycol and propylene glycol; diethylene glycols such as diethylene glycol, diethylene glycol monoethyl ether, and diethylene glycol ethyl butyl ether; ethyl formate, ethyl lactate, and lactic acid Examples include esters such as propyl, methyl benzoate, methyl acetate, and methyl acrylate.
  • a mixture of lacquer, gasoline, naphtha, kerosene, etc. can be used as the non-aqueous medium.
  • water is preferable from the viewpoint of solubility and economy, and it is preferable to adjust the pH of the solution to 6 to 8 using an alkali component such as sodium hydroxide.
  • the content of the copolymer in the entire solution or dispersion is preferably 0.2 to About 70% by mass, more preferably about 0.5 to 60% by mass, still more preferably about 0.5 to 50% by mass, and particularly preferably about 2 to 35% by mass.
  • the pH of the slurry is preferably 4 to 10, more preferably 5 to 9, and still more preferably 6 to 8.
  • the pH is 4 or less, battery performance may be deteriorated due to corrosion of the positive electrode current collector, deterioration of the electrolytic solution, or the positive electrode active material.
  • the pH is 10 or more, the positive electrode current collector composed of a metal such as aluminum is corroded, and the battery performance may be deteriorated.
  • a pH adjusting agent may be used for the purpose of adjusting the pH of the slurry.
  • the pH adjuster include a pH acid adjuster and a pH alkali adjuster.
  • the pH acid adjusting agent include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid; and organic acids such as formic acid, acetic acid, propionic acid, and citric acid.
  • the pH adjusting agent include inorganic alkalis such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; organic alkalis such as ammonia, methylamine, and ethylamine.
  • an additive may be used to improve the coating property of the slurry or improve the charge / discharge characteristics.
  • these additives include cellulose polymers such as carboxymethylcellulose, methylcellulose, and hydroxypropylcellulose, polyacrylates such as sodium polyacrylate, polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, and (meth) acrylic acid-vinyl.
  • examples thereof include alcohol copolymers, maleic acid-vinyl alcohol copolymers, modified polyvinyl alcohol, polyethylene glycol, ethylene-vinyl alcohol copolymers, and polyvinyl acetate partially saponified products.
  • An additive may be used individually by 1 type and may be used in combination of 2 or more types.
  • the use ratio of these additives is not particularly limited, but is preferably less than 300 parts by weight, more preferably 30 parts by weight or more and 250 parts by weight with respect to 100 parts by weight of the alkyl-modified carboxyl group-containing copolymer constituting the binder. Part or less, more preferably 40 parts by mass or more and 200 parts by mass or less. If it is such a range, the electrode excellent in smoothness can be obtained.
  • Such additives may be used by adding to the binder composition, or may be used by adding to the above slurry.
  • acrylic acid acrylic acid metal neutralized salt
  • methacrylic acid metal methacrylate neutralized salt
  • carboxymethyl cellulose hydroxyethyl cellulose, etc.
  • a conventional binder such as a water-soluble compound, a styrene-butadiene copolymer-containing emulsion, a butadiene acrylonitrile copolymer-containing emulsion, a PVdF-containing emulsion, or a polytetrafluoroethane polymer-containing emulsion may be used in combination.
  • the material of the positive electrode current collector is not particularly limited as long as it has electronic conductivity and can supply current to the held positive electrode material.
  • Examples of the material for the positive electrode current collector include conductive substances such as C, Ti, Cr, Mo, Ru, Rh, Ta, W, Os, Ir, Pt, Au, and Al, and two or more kinds of these conductive substances.
  • the shape of the positive electrode current collector is not particularly limited, and examples thereof include a foil shape and a three-dimensional shape.
  • a three-dimensional shape fused metal, mesh, woven fabric, non-woven fabric, expanded, etc.
  • a high capacity density electrode can be obtained even with a binder having low adhesion to the positive electrode current collector, and high rate charge / discharge The characteristics are also good.
  • the primer layer can be formed by applying a binder mixed with a carbon-based conductive additive on the positive electrode current collector to a thickness of 0.1 ⁇ m to 50 ⁇ m.
  • the conductive aid for the primer layer carbon powder is preferable.
  • the capacity density can be increased, but input / output characteristics may be deteriorated.
  • the conductive assistant is carbon-based, the input / output characteristics are easily improved.
  • Examples of the carbon-based conductive assistant include KB, AB, VGCF, graphite, graphene, and carbon tube.
  • a conductive support agent may be used individually by 1 type, and may be used in combination of 2 or more types.
  • KB or AB is preferable from the viewpoint of conductivity and cost.
  • the binder for the primer layer is not limited as long as it can bind the carbon-based conductive aid.
  • an aqueous binder such as the binder of the present invention, PVA, CMC, sodium alginate, etc.
  • the primer layer is melted when the active material layer is formed, and the effect may not be exhibited remarkably. Therefore, when using such an aqueous binder, the primer layer may be crosslinked in advance.
  • the cross-linking material include zirconia compounds, boron compounds, titanium compounds, and the like, and it is preferable to add about 0.1 to 20% by mass with respect to the amount of the binder when forming the primer layer slurry.
  • the primer layer thus produced can improve the capacity density by using an aqueous binder in a foil-like positive electrode current collector. Furthermore, even if charging / discharging is performed at a high current, the polarization is small, so that high rate charge / discharge characteristics are improved.
  • the primer layer has the same effect not only in the foil-shaped positive electrode current collector but also in the three-dimensional positive electrode current collector.
  • the positive electrode for a non-aqueous electrolyte secondary battery of the present invention is, for example, a non-aqueous electrolyte using a positive electrode active material comprising a metal oxide represented by the following composition formula 1 on the surface of active material particles and the binder of the present invention. It may be a positive electrode for a secondary battery.
  • Composition formula 1 Li ⁇ M ⁇ O ⁇
  • M is at least one metal element selected from the group consisting of Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ag, Ta, W, and Ir. 0 ⁇ ⁇ ⁇ 6, 1 ⁇ ⁇ ⁇ 5, and 0 ⁇ ⁇ 12. Among these, from the viewpoint of heat resistance, M is preferably Zr.
  • a positive electrode active material having a metal oxide on the surface of an active material particle means that the metal oxide is provided as an overcoat layer on the electrode surface of the positive electrode, and the metal oxide is a positive electrode active material. That the particle surface is coated, and that both are performed.
  • the positive electrode active material by providing a metal oxide on the surface of the active material particles, a decrease in the positive electrode active material capacity due to the dissolution of lithium in the positive electrode active material, which is a concern when using the aqueous binder as in the present invention, and The oxidative decomposition of the aqueous binder during charging can be prevented, and the high rate discharge characteristics can be further improved.
  • a positive electrode active material having an operating voltage exceeding 4 V can be used in a conventional electrolyte.
  • the transition metal lithium phosphate compound in which the transition metal is Ni or Co has a very high divalent to tetravalent or tetravalent to divalent redox potential, and thus may take electrons from the electrolyte and oxidatively decompose.
  • metal oxide as an overcoat layer on the electrode surface of the positive electrode and covering the surface of the active material particles with the metal oxide.
  • a method for coating the surface of the active material particles with the metal oxide is not particularly limited, and a conventional method such as a dipping method in which a predetermined amount of the active material powder is added to a predetermined amount of the coating liquid containing the metal oxide and then mixed.
  • a simpler method includes a method in which metal oxide fine particles are sprayed on the active material particles by spraying. According to this method, the surface of the active material particles can be suitably coated with the metal oxide.
  • the spray coating method can be performed easily and is advantageous in terms of cost.
  • a similar method can be used for coating a metal oxide on the electrode surface.
  • the thickness of the metal oxide overcoat layer on the electrode surface is preferably about 0.1 to 10 ⁇ m. If the thickness is less than 0.1 ⁇ m, there may be a case where the decrease in the positive electrode active material capacity and the oxidative decomposition of the aqueous binder during charging cannot be sufficiently prevented. On the other hand, when the thickness exceeds 10 ⁇ m, not only the electrode thickness increases and the battery capacity decreases, but also the high-rate discharge characteristics tend to deteriorate because the battery impedance is improved.
  • the positive electrode active material can include a mixture of a metal oxide and a conductive additive on the surface of the active material particles.
  • a method in which a mixture of a metal oxide and a carbon precursor is previously provided on the particle surface and carbonized by a heat treatment method may be employed.
  • the heat treatment method is a non-oxidizing atmosphere (reducing atmosphere, inert atmosphere, reduced pressure atmosphere, etc., which is difficult to oxidize), and heat treatment is performed at about 600 to 4,000 ° C. to carbonize the carbon precursor, This is a method of developing conductivity.
  • the carbon precursor is not particularly limited as long as it can be a carbon material by heat treatment, and examples thereof include glucose, citric acid, pitch, tar, and a binder material used for an electrode.
  • the proportion of the carbon precursor is preferably about 0.5 to 20% by mass.
  • the proportion of the carbon precursor is less than 0.5% by mass, the conductivity of the positive electrode may not be sufficiently improved.
  • the proportion of the carbon precursor exceeds 20% by mass, the carbon repels water during the production of the aqueous slurry, so that it is difficult to uniformly disperse and the possibility of causing the aggregation of the positive electrode active material tends to increase. is there.
  • the positive electrode active material is a carbon-coated powder or when a carbon-based conductive aid is used, the carbon repels water during the preparation of the aqueous slurry, so that the positive electrode active material is uniformly in the slurry. It is difficult to disperse and the possibility of causing aggregation of the positive electrode active material increases. In that case, it is preferable to add a surfactant to the slurry.
  • a surfactant saponins, phospholipids, peptides, tritons and the like are effective, and about 0.01 to 0.1% by mass of the surfactant may be added to the whole slurry.
  • the binder for an electrode of the nonaqueous electrolyte secondary battery of the present invention can effectively suppress the peeling of the electrode mixture from the current collector and the detachment of the active material, and repeated charge and discharge. In addition, it has excellent binding durability. Therefore, by using the binder of the present invention for the negative electrode, a nonaqueous electrolyte secondary battery having a large battery capacity and excellent charge / discharge cycle characteristics can be obtained.
  • the negative electrode in the present invention is manufactured, for example, as follows.
  • a negative electrode active material, a conductive additive, a binder of the present invention, and a liquid medium such as water are mixed to form a paste slurry as a negative electrode mixture.
  • a negative electrode for the non-aqueous electrolyte secondary battery of the present invention can be obtained.
  • the binder of the present invention may be used by previously dissolving in a liquid medium, or the powdered binder of the present invention and a negative electrode active material may be mixed in advance, and then the liquid medium may be added and used.
  • the negative electrode active material is not particularly limited, and a material that can occlude and release a large amount of lithium ions, such as silicon (Si) or tin (Sn), can be used. With such a material, the effect of the present invention can be exhibited with any of a simple substance, an alloy, a compound, a solid solution, and a composite active material including a silicon-containing material and a tin-containing material.
  • Examples of the silicon-containing material include Si, SiO x (0.05 ⁇ x ⁇ 1.95), or any of them, B, Mg, Ni, Ti, Mo, Co, Ca, Cr, Cu, Fe, Mn, An alloy, compound, solid solution, or the like in which a part of Si is substituted with at least one element selected from the group consisting of Nb, Ta, V, W, Zn, C, N, and Sn can be used. These can be referred to as silicon or silicon compounds.
  • Examples of the tin-containing material include Ni 2 Sn 4 , Mg 2 Sn, SnO x (0 ⁇ x ⁇ 2), SnO 2 , SnSiO 3 , and LiSnO. Among these, silicon or silicon compounds such as Si alone or silicon oxide are preferable.
  • a negative electrode active material may be used individually by 1 type, and may be used in combination of 2 or more types.
  • Silicon or a silicon compound is used as the first negative electrode active material, the carbon material is used as the second negative electrode active material, and the first negative electrode active material and the second negative electrode active material can be used alone, respectively. It is more preferable to use a composite obtained by mixing as a negative electrode active material. At this time, the mixing ratio of the first and second negative electrode active materials is preferably about 5/95 to 95/5 in mass ratio.
  • any carbon material that is generally used in non-aqueous electrolyte secondary batteries can be used.
  • crystalline carbon, amorphous carbon, or a combination thereof may be used.
  • crystalline carbon include amorphous, plate-like, flake, spherical or fibrous natural graphite, or graphite such as artificial graphite.
  • amorphous carbon include soft carbon, hard carbon, mesophase pitch carbide, calcined coke, and the like.
  • amorphous carbon is preferable, and soft carbon is more preferable in terms of low manufacturing cost because it has a low processing temperature at the time of manufacturing and low cost.
  • the method for producing the negative electrode active material is not particularly limited. Moreover, when manufacturing the negative electrode active material composite which mixed said 1st negative electrode active material and 2nd negative electrode active material, if it is a method by which both are disperse
  • An example of a method for mixing and manufacturing the first negative electrode active material and the second negative electrode active material is a method of mixing both active materials in a ball mill.
  • a method for producing the negative electrode active material composite for example, a method in which the second negative electrode active material precursor is supported on the particle surface of the first negative electrode active material and carbonized by a heat treatment method may be employed. .
  • the precursor of the second negative electrode active material is not particularly limited as long as it is a carbon precursor that can be converted into a carbon material by heat treatment, and examples thereof include glucose, citric acid, pitch, tar, and binder materials used for electrodes. .
  • the binder material for example, in addition to the alkyl-modified carboxyl group-containing copolymer of the present invention, polyvinylidene fluoride (PVdF), carboxymethyl cellulose (CMC), acrylic resin, sodium polyacrylate, sodium alginate, polyimide (PI), Examples include polytetrafluoroethylene (PTFE), polyamide, polyamideimide, polyacryl, styrene butadiene rubber (SBR), polyvinyl alcohol (PVA), and ethylene acetate copolymer (EVA).
  • the heat treatment method is a non-oxidizing atmosphere (reducing atmosphere, inert atmosphere, reduced pressure atmosphere, etc., which is difficult to oxidize), heat treatment is performed at 600 to 4,000 ° C. to carbonize the carbon precursor, and conductive It is a way to get sex.
  • reducing atmosphere inert atmosphere, reduced pressure atmosphere, etc., which is difficult to oxidize
  • heat treatment is performed at 600 to 4,000 ° C. to carbonize the carbon precursor, and conductive It is a way to get sex.
  • the conductive aid is not particularly limited as long as it has conductivity, but is preferably carbon nanofiber or carbon nanotube which is fibrous carbon.
  • the amount used is not particularly limited, but is preferably 30 to 100% by mass, and more preferably 40 to 100% by mass of the total conductive auxiliary.
  • the amount of carbon nanofibers or carbon nanotubes used is less than 30% by mass, a sufficient conductive path is not ensured between the negative electrode active material and the negative electrode current collector, and a sufficient conductive path cannot be formed particularly in high-speed charge / discharge. There is a case.
  • the amount of the conductive aid used is not particularly limited, but for example, it is preferably about 0.1 to 20% by weight, more preferably 0.5 to 0.5% with respect to the total weight of the negative electrode active material, the conductive aid and the binder. About 10% by mass, more preferably about 2-5% by mass.
  • the proportion of the conductive aid is less than 0.1% by mass, it is difficult to sufficiently improve the conductivity of the negative electrode.
  • the proportion of the conductive additive exceeds 20% by mass, the proportion of the negative electrode active material is relatively reduced, so that it is difficult to obtain a high capacity during charging / discharging of the battery, and when water is used as the liquid medium. Since carbon repels water, it is difficult to uniformly disperse, causing aggregation of the active material, and since it is small compared to the active material, the surface area increases and the amount of binder used increases.
  • the amount of the binder of the present invention used in the negative electrode is not particularly limited, but is preferably 0.5% by mass or more and 30% by mass or less with respect to the total mass of the negative electrode active material, the conductive additive, and the binder, for example. More preferably, 2 mass% or more and 20 mass% or less, More preferably, 3 mass% or more and 12 mass% or less are mentioned. If the amount of the binder is too large, the ratio of the negative electrode active material is relatively reduced, so that it is difficult to obtain a high capacity during charging / discharging of the battery, and conversely, if the amount is too small, the binding force is not sufficient, and the charge / discharge cycle characteristics are reduced. End up.
  • the negative electrode active material is a powder coated with carbon or when a carbon-based conductive additive is used, the carbon repels water during the preparation of the aqueous slurry, so the negative electrode active material is uniformly in the slurry. It is difficult to disperse, and the possibility of causing aggregation of the negative electrode active material increases. In that case, it is preferable to add a surfactant to the slurry.
  • surfactant examples include saponin, phospholipid, peptide, octyl glucoside, sodium dodecyl sulfate, polyoxylene, sorbitan monolaurate, polyoxylen sorbitan monooleate, ethyl ether, polysorbate, deoxycholate, and triton.
  • the surfactant may be added in an amount of about 0.01 to 0.1% by mass relative to the total amount of the mixture.
  • the amount of the liquid medium used for the negative electrode mixture is not particularly limited, but for example, about 40 to 900% by mass is preferable with respect to the total mass of the negative electrode active material, the conductive auxiliary agent, and the binder.
  • the amount of the liquid medium is less than 40% by mass, the viscosity of the prepared slurry is increased, so that the negative electrode active material, the conductive auxiliary agent, and the binder are difficult to uniformly disperse.
  • the amount of the liquid medium exceeds 900% by mass, the ratio of the liquid medium is too large. For example, when water is used as the liquid medium and a carbon-based conductive assistant is used, the carbon repels water, so that it is difficult to uniformly disperse and the possibility of causing aggregation of the active material increases.
  • the negative electrode current collector is not particularly limited as long as it is a material that has electronic conductivity and can conduct electricity to the held negative electrode active material.
  • the negative electrode current collector include conductive materials such as C, Cu, Ni, Fe, V, Nb, Ti, Cr, Mo, Ru, Rh, Ta, W, Os, Ir, Pt, Au, and Al. Examples thereof include materials and alloys containing two or more of these conductive materials (for example, stainless steel). Moreover, what plated Cu on Fe may be used. From the viewpoint of high electrical conductivity and good stability and oxidation resistance in the electrolytic solution, the negative electrode current collector is preferably C, Cu, Ni, stainless steel or the like, and more preferably Cu or Ni from the viewpoint of material cost. .
  • the shape of the negative electrode current collector is not particularly limited, and examples thereof include a foil shape and a three-dimensional shape.
  • a three-dimensional shape (foam metal, mesh, woven fabric, nonwoven fabric, expanded base material, etc.) is used, a high capacity density electrode can be obtained even with a binder having low adhesion to the negative electrode current collector. Charge / discharge characteristics are also improved.
  • the binder for an electrode of the nonaqueous electrolyte secondary battery of the present invention can effectively suppress the peeling of the electrode mixture from the current collector and the detachment of the active material, and repeated charge and discharge. In addition, it has excellent binding durability. For this reason, the nonaqueous electrolyte secondary battery of the present invention using the binder of the present invention as an electrode (at least one of a positive electrode and a negative electrode) has a large battery capacity and excellent charge / discharge cycle characteristics (battery life characteristics). .
  • the nonaqueous electrolyte secondary battery includes a capacitor and a capacitor.
  • the non-aqueous electrolyte secondary battery of the present invention is preferably a lithium ion secondary battery.
  • a lithium salt as the electrolyte.
  • the lithium salt is not particularly limited, and specific examples include lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, and lithium trifluoromethanesulfonate. These lithium salts may be used alone or in combination of two or more. Since the above lithium salt has high electronegativity and is easily ionized, it has excellent charge / discharge cycle characteristics and can improve the charge / discharge capacity of the secondary battery.
  • the electrolyte solvent examples include propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ⁇ -butyrolactone. These solvents may be used alone or in combination of two or more.
  • the solvent propylene carbonate alone, a mixture of ethylene carbonate and diethyl carbonate or ⁇ -butyrolactone alone is particularly suitable.
  • the mixing ratio of the mixture of ethylene carbonate and diethyl carbonate can be arbitrarily adjusted in a range where one component is 10% by volume or more and 90% by volume or less.
  • the electrolyte of the nonaqueous electrolyte secondary battery of the present embodiment may be a solid electrolyte or an ionic liquid.
  • the structure of the nonaqueous electrolyte secondary battery is not particularly limited, and examples thereof include existing battery forms and structures such as a stacked battery and a wound battery.
  • the nonaqueous electrolyte secondary battery using the binder of the present invention for at least one of the positive electrode and the negative electrode can function as a nonaqueous electrolyte secondary battery excellent in charge / discharge cycle characteristics.
  • the non-aqueous electrolyte secondary battery provided with the electrode for non-aqueous electrolyte secondary battery of the present invention has a high capacity and excellent charge / discharge cycle characteristics, and is a power source for various electric devices (including vehicles using electricity). Can be suitably used.
  • electrical equipment include air conditioners, washing machines, televisions, refrigerators, freezers, air conditioners, notebook computers, tablets, smartphones, computer keyboards, computer displays, desktop computers, CRT monitors, printers, integrated computers, mice , Hard disk, computer peripherals, iron, clothes dryer, window fan, walkie-talkie, blower, ventilation fan, TV, music recorder, music player, oven, range, toilet seat with washing function, hot air heater, car component, car navigation, flashlight, Humidifier, portable karaoke machine, ventilation fan, dryer, air cleaner, mobile phone, emergency light, game machine, blood pressure monitor, coffee mill, coffee maker, kotatsu, copy machine, disk changer, radio, juicer, shredder Water purifier, lighting equipment, dehumidifier, dish dryer, rice cooker, stereo, stove, speaker, trouser press, vacuum cleaner, body fat scale, weight scale, health meter, movie player, electric carpet, electric kettle, electric razor, Desk lamp, electric kettle, electronic game machine, portable game machine, electronic dictionary, electronic notebook, microwave oven, electromagnetic cooker,
  • the electrolyte was poured into the container so that no air remained.
  • a 0.2 mm-thick stainless steel cap was placed on the outer container through polypropylene packing, and the battery can was sealed to produce a coin-type battery having a diameter of 20 mm and a thickness of about 2 mm.
  • the electrolytic solution 1 of ethylene carbonate and diethyl carbonate: a LiPF 6 was obtained by dissolving at a rate of 1 mol / l in 2 (by volume) mixture.
  • Example 1 In a 500 mL four-necked flask equipped with a stirrer, thermometer, nitrogen blowing tube and cooling tube, 45 g (0.625 mol) of acrylic acid and (meth) acrylic acid having an alkyl group with 18 to 24 carbon atoms BLEMMER VMA70 as an alkyl ester (manufactured by NOF Corporation, stearyl methacrylate 10-20 parts by mass, eicosanyl methacrylate 10-20 parts by mass, behenyl methacrylate 59-80 parts by mass, tetracosanyl methacrylate content 1 part by mass 0.45 g of the following mixture), 150 g of normal hexane, and 0.081 g (0.00035 mol) of 2,2′-azobismethylisobutyrate were charged.
  • BLEMMER VMA70 as an alkyl ester
  • Example 2 In Example 1, it replaced with Blemmer VMA70 (Nippon Yushi Co., Ltd.) 0.45g, and it was carried out similarly to Example 1 except having used 1.35 g of behenyl acrylate (Nippon Yushi Co., Ltd. Blemmer VA). 44 g of an alkyl-modified carboxyl group-containing copolymer (b) in the form of white fine powder was obtained.
  • Example 3 In Example 1, it replaced with 0.45g of Blemmer VMA70 (Nippon Yushi Co., Ltd.) 0.45g, It was carried out similarly to Example 1 except having used 2.25 g of stearyl methacrylate (Nippon Yushi Co., Ltd. Blemmer SMA). As a result, 45 g of an alkyl-modified carboxyl group-containing copolymer (c) in the form of white fine powder was obtained.
  • Example 4 In Example 1, acrylic acid 45 g (0.625 mol), Blemmer VMA70 (manufactured by NOF Corporation) 0.45 g, normal hexane 150 g, 2,2′-azobismethylisobutyrate 0.081 g (0.00035) In addition to using 0.02 g of pentaerythritol allyl ether, 43 g of an alkyl-modified carboxyl group-containing copolymer (d) in the form of a white fine powder was obtained in the same manner as in Example 1.
  • Example 5 In Example 4, it replaced with Blemmer VMA70 (Nippon Yushi Co., Ltd.) 0.45g, and it was carried out similarly to Example 4 except having used 1.35g of acrylic acid behenyl (Nippon Yushi Co., Ltd. Blemmer VA). 44 g of an alkyl-modified carboxyl group-containing copolymer (e) in the form of a white fine powder was obtained.
  • Example 6 In Example 4, it replaced with Blemmer VMA70 (Nippon Yushi Co., Ltd.) 0.45g, and used the same method as Example 4 except having used 2.25g of stearyl methacrylate (Nippon Yushi Co., Ltd. Blemmer SMA). Thus, 45 g of an alkyl-modified carboxyl group-containing copolymer (f) in the form of a white fine powder was obtained.
  • the resulting slurry was heated to 90 ° C. to distill off normal hexane, and further dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 42 g of white fine powdery polymer (g). Obtained.
  • Example 2 (Comparative Example 2) In Example 1, except that 0.45 g of lauryl methacrylate (Blemmer LMA manufactured by NOF Corporation) was used instead of 0.45 g of BLEMMER VMA (manufactured by NOF Corporation), the same as in Example 1, 46 g of an alkyl-modified carboxyl group-containing copolymer (h) in the form of white fine powder was obtained.
  • lauryl methacrylate (Blemmer LMA manufactured by NOF Corporation) was used instead of 0.45 g of BLEMMER VMA (manufactured by NOF Corporation)
  • BLEMMER VMA manufactured by NOF Corporation
  • Tables 1 and 2 show the main raw materials used in Examples 1 to 6 and Comparative Examples 1 and 2 and the amounts used. The values in parentheses indicate the mass% of each raw material when the mass of (meth) acrylic acid used is 100.
  • Example 7 1 g of the alkyl-modified carboxyl group-containing copolymer (a) obtained in Example 1 was dissolved in water, and the pH was adjusted to 6 to 8 using a 6% by mass sodium hydroxide aqueous solution to obtain a 10% by mass binder aqueous solution. Produced. Water was added to 50 parts by mass of the obtained binder aqueous solution, 91 parts by mass of lithium iron phosphate as the positive electrode active material, and 4 parts by mass of carbon nanotubes as the conductive auxiliary agent, and stirred to obtain a slurry having a solid content concentration of 50% by mass. Prepared.
  • the obtained slurry was applied to an aluminum foil, dried at 140 ° C. for 12 hours, and then subjected to a roll press to obtain a positive electrode.
  • a bending test was performed by the above method.
  • the results are shown in Table 3.
  • N-methylpyrrolidone was added to 95 parts by mass of natural graphite as a negative electrode active material, 2 parts by mass of carbon nanotubes as a conductive auxiliary agent, and 3 parts by mass of PVdF and stirred to prepare a slurry having a solid content concentration of 50% by mass.
  • the obtained slurry was applied to a copper foil and dried at 140 ° C. for 12 hours to obtain a negative electrode.
  • a non-aqueous electrolyte secondary battery was produced, and the battery characteristics were evaluated.
  • the results are shown in Table 3.
  • Example 8 A positive electrode was obtained in the same manner as in Example 7, except that 1 g of the alkyl-modified carboxyl group-containing copolymer (b) was used instead of 1 g of the alkyl-modified carboxyl group-containing copolymer (a) in Example 7. It was. Using the obtained positive electrode, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 7, and the battery characteristics were evaluated. The results are shown in Table 3.
  • Example 9 In Example 7, instead of 1 g of the alkyl-modified carboxyl group-containing copolymer (a), 1 g of the alkyl-modified carboxyl group-containing copolymer (c) was dissolved in water, and the pH was adjusted using a 6% by mass aqueous sodium hydroxide solution. After preparing a 10% by weight binder aqueous solution by adjusting to 6-8, 80 parts by weight of the obtained binder aqueous solution, 88 parts by weight of lithium iron phosphate as the positive electrode active material, and 4 parts by weight of carbon nanotubes as the conductive assistant A positive electrode was obtained in the same manner as in Example 7 except that water was added and stirred. Using the obtained positive electrode, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 7, and the battery characteristics were evaluated. The results are shown in Table 3.
  • Example 10 In Example 7, instead of 1 g of the alkyl-modified carboxyl group-containing copolymer (a), 0.5 g of the alkyl-modified carboxyl group-containing copolymer (d) was dissolved in water, and a 6% by mass sodium hydroxide aqueous solution was used. After adjusting the pH to 6 to 8 to prepare a 4% by mass binder aqueous solution, the obtained binder aqueous solution 50 parts by mass, 94 parts by mass of lithium iron phosphate as a positive electrode active material, 4 parts by mass of carbon nanotubes as a conductive assistant A positive electrode was obtained in the same manner as in Example 7 except that water was added and stirred. Using the obtained positive electrode, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 7, and the battery characteristics were evaluated. The results are shown in Table 3.
  • Example 11 In Example 10, instead of 0.5 g of the alkyl-modified carboxyl group-containing copolymer (d), 0.5 g of the alkyl-modified carboxyl group-containing copolymer (e) was dissolved in water, and a 6% by mass aqueous sodium hydroxide solution A positive electrode was obtained in the same manner as in Example 10 except that the pH was adjusted to 6 to 8 to prepare a 10% by mass aqueous binder solution. Using the obtained positive electrode, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 7, and the battery characteristics were evaluated. The results are shown in Table 3.
  • Example 12 In Example 10, instead of 0.5 g of the alkyl-modified carboxyl group-containing copolymer (d), 0.5 g of the alkyl-modified carboxyl group-containing copolymer (f) was dissolved in water, and a 6% by mass aqueous sodium hydroxide solution A positive electrode was obtained in the same manner as in Example 10 except that the pH was adjusted to 6 to 8 to prepare a 10% by mass aqueous binder solution. Using the obtained positive electrode, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 7, and the battery characteristics were evaluated. The results are shown in Table 3.
  • Example 13 In preparation of the negative electrode of Example 7, water was added to 95 parts by mass of natural graphite, 2 parts by mass of carbon nanotubes and 3 parts by mass of the alkyl-modified carboxyl group-containing copolymer (a) as a conductive additive, and 6 masses was stirred.
  • a negative electrode was obtained in the same manner as in Example 7 except that a negative electrode was obtained by adjusting the pH to 6 to 8 using a% sodium hydroxide aqueous solution and preparing a slurry having a solid content of 50% by mass.
  • a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 7, and the battery characteristics were evaluated. The results are shown in Table 3.
  • Example 7 (Comparative Example 3) In Example 7, instead of 1 g of the alkyl-modified carboxyl group-containing copolymer (a), 0.5 g of the polymer (g) obtained in Comparative Example 1 was dissolved in water, and a 6 mass% sodium hydroxide aqueous solution was used. After adjusting pH to 6-8 and preparing 3 mass% binder aqueous solution, 100 mass parts of obtained binder aqueous solution, 93 mass parts of lithium iron phosphate as a positive electrode active material, 4 mass parts of carbon nanotubes as a conductive support agent A positive electrode was obtained in the same manner as in Example 7 except that water was added and stirred. Using the obtained positive electrode, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 7, and the battery characteristics were evaluated. The results are shown in Table 3.
  • Example 7 is the same as Example 7 except that 1 g of the alkyl-modified carboxyl group-containing copolymer (h) obtained in Comparative Example 2 is used instead of 1 g of the alkyl-modified carboxyl group-containing copolymer (a). Thus, a positive electrode was obtained. Using the obtained positive electrode, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 7, and the battery characteristics were evaluated. The results are shown in Table 3.

Abstract

　Provided is a binder for an electrode of a non-aqueous electrolyte secondary cell enabling effective suppression of separation of an electrode mixture from a collector and desorption of an active material, and having excellent binding consistency even under repeated charging and discharging. The binder for an electrode of a non-aqueous electrolyte secondary cell comprises an alkyl-modified carboxyl-group-containing copolymer obtained by copolymerizing (meth)acrylic acid and a (meth)acrylic acid alkyl ester in which the alkyl group has 18-24 carbons.

Description

非水電解質二次電池の電極用バインダー、当該バインダーを含む非水電解質二次電池用電極、及び当該電極を備える非水電解質二次電池Nonaqueous electrolyte secondary battery electrode binder, nonaqueous electrolyte secondary battery electrode including the binder, and nonaqueous electrolyte secondary battery including the electrode
　本発明は、集電体からの電極用合剤の剥離や活物質の脱離を効果的に抑制することができ、充放電の繰り返しに対しても優れた結着持続性を有する非水電解質二次電池の電極用バインダー、当該バインダーを含む非水電解質二次電池用電極、及び当該電極を備える非水電解質二次電池に関する。 The present invention is a non-aqueous electrolyte that can effectively suppress the peeling of an electrode mixture and the detachment of an active material from a current collector, and has excellent binding durability even when charging and discharging are repeated. It is related with the binder for electrodes of a secondary battery, the electrode for nonaqueous electrolyte secondary batteries containing the said binder, and a nonaqueous electrolyte secondary battery provided with the said electrode.
　近年、ノートパソコン、スマートフォン、携帯ゲーム機器、携帯情報端末等の携帯電子機器が急速に普及している。これらの機器の長時間の使用を可能とするために、電源として使用される二次電池には、高容量化、優れた充放電サイクル特性が要求されている。 In recent years, portable electronic devices such as notebook computers, smartphones, portable game devices, and portable information terminals are rapidly spreading. In order to enable long-time use of these devices, secondary batteries used as a power source are required to have a high capacity and excellent charge / discharge cycle characteristics.
　また、近年、電気自動車、電動二輪車等の車両用電源としての二次電池の利用も拡大している。このような車両用電源に使用される二次電池においても、高容量化、優れた充放電サイクル特性が求められている。 In recent years, the use of secondary batteries as power sources for vehicles such as electric cars and electric motorcycles has also been expanded. Also in a secondary battery used for such a vehicle power source, a high capacity and excellent charge / discharge cycle characteristics are required.
　非水電解質二次電池としては、従来、ニッケル－カドミウム電池、ニッケル－水素電池等が主流であったが、上記した高容量化、優れた充放電サイクル特性などの要請に加えて、小型化などの観点から、リチウムイオン二次電池の使用が増加する傾向にある。 As non-aqueous electrolyte secondary batteries, nickel-cadmium batteries and nickel-hydrogen batteries have been the mainstream, but in addition to the above demands for higher capacity and excellent charge / discharge cycle characteristics, etc. From this point of view, the use of lithium ion secondary batteries tends to increase.
　非水電解質二次電池の電極は、通常、電極用バインダー（以下、単にバインダーということがある）を溶媒に溶解させたバインダー溶液、または分散媒に分散させた分散液に対して、活物質及び導電助剤を混合した電極用合剤スラリー（以下、単にスラリーということがある）を集電体に塗布し、溶媒や分散媒を乾燥などの方法で除去して、活物質、導電助剤及び集電体の各間を結着させて製造される。 The electrode of the non-aqueous electrolyte secondary battery is generally composed of an active material and a binder solution in which a binder for an electrode (hereinafter sometimes simply referred to as a binder) is dissolved in a solvent, or a dispersion in which a dispersion medium is dispersed. An electrode mixture slurry mixed with a conductive additive (hereinafter sometimes simply referred to as a slurry) is applied to a current collector, and the solvent or dispersion medium is removed by a method such as drying to obtain an active material, a conductive additive, and It is manufactured by binding the current collectors.
　例えば、非水電解質二次電池の正極は、一般に、正極活物質としてコバルト酸リチウム（ＬｉＣｏＯ2）を、バインダーとしてポリフッ化ビニリデン（ＰＶｄＦ）を、導電助剤としてカーボンブラックを分散媒に分散させた正極合剤のスラリーをアルミ箔集電体上に塗工・乾燥することで得られる。 For example, the positive electrode of a non-aqueous electrolyte secondary battery is generally obtained by dispersing lithium cobaltate (LiCoO 2 ) as a positive electrode active material, polyvinylidene fluoride (PVdF) as a binder, and carbon black as a conductive additive in a dispersion medium. It is obtained by coating and drying a slurry of the positive electrode mixture on an aluminum foil current collector.
　一方、負極は、一般に、負極活物質としてグラファイトを、バインダーとしてカルボキシメチルセルロース（ＣＭＣ）、スチレンブタジエンゴム（ＳＢＲ）、ＰＶｄＦまたはポリイミドを、導電助剤としてカーボンブラックを分散媒に分散させた負極合剤のスラリーを、銅箔集電体上に塗工・乾燥することで得られる。 On the other hand, the negative electrode generally includes graphite as a negative electrode active material, carboxymethyl cellulose (CMC), styrene butadiene rubber (SBR), PVdF or polyimide as a binder, and carbon black as a conductive additive in a dispersion medium. This slurry is obtained by coating and drying on a copper foil current collector.
　非水電解質二次電池において、電池容量、充放電サイクル特性、レート特性などの特性は、活物質の種類や量、電解液の種類や量に加えて、バインダーも重要な決定要因となる。バインダーが十分な量の活物質を集電体に結着できない場合や、活物質同士を結着できない場合には、容量の大きな電池は得られない。また、充放電を繰り返すことによる活物質の体積変動などによって、バインダーの結着力が低下すると、集電体から活物質が脱落して電池の容量が低下する。さらに、バインダーが活物質を被覆して表面を隠蔽すると、電池反応が妨げられ、電池容量、充放電サイクル特性、レート特性が低下してしまう。 In a non-aqueous electrolyte secondary battery, in addition to the type and amount of active material and the type and amount of electrolyte, binders are important determinants of characteristics such as battery capacity, charge / discharge cycle characteristics, and rate characteristics. When the binder cannot bind a sufficient amount of the active material to the current collector or when the binder cannot bind the active materials, a battery having a large capacity cannot be obtained. In addition, when the binding force of the binder is reduced due to a change in the volume of the active material due to repeated charge and discharge, the active material is dropped from the current collector and the capacity of the battery is reduced. Further, when the binder covers the active material and conceals the surface, the battery reaction is hindered, and the battery capacity, charge / discharge cycle characteristics, and rate characteristics deteriorate.
　このように、バインダーには、活物質－集電体間及び活物質間の強い結着性と、充放電の繰り返しによっても活物質を集電体から脱落させないための結着持続性が要求され、かつ、活物質を面で被覆せずに線や点で被覆して活物質の表面を露出させることが求められる。 As described above, the binder is required to have a strong binding property between the active material and the current collector and between the active materials, and to maintain the binding property so that the active material does not fall off the current collector even after repeated charge and discharge. In addition, it is required to expose the surface of the active material by covering the active material with lines or dots without covering the active material with a surface.
　非水電解質二次電池の電極用バインダーとしては、ポリフッ化ビニリデン（ＰＶｄＦ）が工業的に多用されている。例えば、特許文献１，２においては、ＰＶｄＦをＮ－メチルピロリドンなどに溶解して電極用バインダー組成物とした後、活物質を混合してスラリーとし、これを集電体に塗布、乾燥して二次電池用電極を形成している。しかしながら、フッ素系ポリマーのＰＶｄＦは、活物質に対する隠蔽性が少ないという長所を有しながら、結着力と柔軟性が不足している。このため、バインダーを多量に使用する必要があり、バインダーが活物質を隠蔽してしまうという問題がある。また、バインダーを多量に使用するために、電極における活物質の割合が減少するという問題もある。さらに、ＰＶｄＦでは、電極の寿命特性や高率放電特性が低下するという問題もある。 Polyvinylidene fluoride (PVdF) is widely used industrially as a binder for electrodes of non-aqueous electrolyte secondary batteries. For example, in Patent Documents 1 and 2, PVdF is dissolved in N-methylpyrrolidone or the like to form a binder composition for an electrode, and then an active material is mixed to form a slurry, which is applied to a current collector and dried. A secondary battery electrode is formed. However, PVdF, which is a fluorine-based polymer, has the advantage of low concealment with respect to the active material, but lacks binding power and flexibility. For this reason, it is necessary to use a binder in large quantities, and there is a problem that the binder conceals the active material. Moreover, since the binder is used in a large amount, there is a problem that the ratio of the active material in the electrode is reduced. Furthermore, PVdF also has a problem that the life characteristics and high-rate discharge characteristics of the electrode deteriorate.
　これに対して、特許文献３，４には、充放電の繰り返しによる活物質の体積変動によっても、結着力を低下させないために、ゴム質重合体であるラテックスをバインダー組成物に使用する方法が開示されている。しかしながら、この方法では、アルミや銅などの集電体に塗工した電極をプレスした際、ゴム弾性のために圧密化が阻害される問題がある。さらに、ゴム質重合体のラテックスだけでは粘性が不足するため、電極スラリーを塗工することができず、カルボキシルメチルセルロース、ポリビニルアルコール、ポリアクリル酸などの増粘剤と合わせて使用する必要がある。このため、これら複合バインダーが活物質の表面を被覆、隠蔽してしまい、電池容量を減少させたり、特に、十分なレート特性が必ずしも得られないという問題がある。 On the other hand, in Patent Documents 3 and 4, there is a method in which latex, which is a rubbery polymer, is used for the binder composition in order not to reduce the binding force even by the volume fluctuation of the active material due to repeated charge and discharge. It is disclosed. However, in this method, there is a problem that, when an electrode coated on a current collector such as aluminum or copper is pressed, consolidation is inhibited due to rubber elasticity. Further, since the viscosity of the latex of the rubbery polymer is insufficient, the electrode slurry cannot be applied, and it is necessary to use it together with a thickener such as carboxymethyl cellulose, polyvinyl alcohol, polyacrylic acid and the like. For this reason, there is a problem that these composite binders cover and conceal the surface of the active material, thereby reducing the battery capacity, and in particular, sufficient rate characteristics cannot always be obtained.
特開平１０－０６４５４７号公報Japanese Patent Laid-Open No. 10-064547 特開平１０－１０６５４１号公報Japanese Patent Laid-Open No. 10-106541 特開平１１―２８８７１８号公報JP-A-11-288718 特開平５－７４４６１号公報JP-A-5-74461
　本発明は、上記従来技術の現状に鑑みてなされたものであり、その主な目的は、集電体からの電極用合剤の剥離や活物質の脱離を効果的に抑制することができ、充放電の繰り返しに対しても優れた結着持続性を有する非水電解質二次電池の電極用バインダー、当該バインダーを含む非水電解質二次電池用電極、当該電極を用い、電池容量が大きく、優れた充放電サイクル特性を有する非水電解質二次電池、及び当該電池を用いた電気機器を提供することにある。 The present invention has been made in view of the current state of the prior art described above, and its main purpose is to effectively suppress the peeling of the electrode mixture and the detachment of the active material from the current collector. , Non-aqueous electrolyte secondary battery electrode binders having excellent binding durability against repeated charge and discharge, non-aqueous electrolyte secondary battery electrodes containing the binder, and using the electrodes, the battery capacity is large Another object of the present invention is to provide a nonaqueous electrolyte secondary battery having excellent charge / discharge cycle characteristics, and an electric device using the battery.
　本発明者らは、上記課題を解決するために鋭意検討した。その結果、特定の共重合体からなる非水電解質二次電池の電極用バインダーは、集電体からの電極用合剤の剥離や活物質の脱離を効果的に抑制することができ、充放電の繰り返しに対しても優れた結着持続性を有することを見出した。さらに、当該バインダーを非水電解質二次電池の電極用バインダーとして用いることにより、電池容量が大きく、優れた充放電サイクル特性を有する非水電解質二次電池が得られることを見出した。本発明は、このような知見に基づき、さらに鋭意検討を重ねて完成された発明である。 The present inventors diligently studied to solve the above problems. As a result, the electrode binder of the non-aqueous electrolyte secondary battery made of a specific copolymer can effectively suppress the peeling of the electrode mixture and the detachment of the active material from the current collector. It has been found that it has excellent binding durability even with repeated discharge. Furthermore, it has been found that by using the binder as an electrode binder for a non-aqueous electrolyte secondary battery, a non-aqueous electrolyte secondary battery having a large battery capacity and excellent charge / discharge cycle characteristics can be obtained. The present invention is an invention which has been completed based on such findings and further earnest studies.
　すなわち、本発明は、下記に掲げる態様の発明を提供する。
項１．　（メタ）アクリル酸と、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルとを共重合させたアルキル変性カルボキシル基含有共重合体からなる、非水電解質二次電池の電極用バインダー。
項２．　前記（メタ）アクリル酸１００質量部に対して、前記アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルが０．１～１０質量部の割合で共重合されてなる、項１に記載の非水電解質二次電池の電極用バインダー。
項３．　エチレン性不飽和基を２個以上有する化合物が、前記（メタ）アクリル酸１００質量部に対して０．５質量部以下の割合で共重合されてなる、項１または２に記載の非水電解質二次電池の電極用バインダー。
項４．　前記エチレン性不飽和基を２個以上有する化合物が、ペンタエリトリトールアリルエーテル、ジエチレングリコールジアリルエーテル、ポリエチレングリコールジアリルエーテル、及びポリアリルサッカロースからなる群から選択された少なくとも１種である、項３に記載の非水電解質二次電池の電極用バインダー。
項５．　活物質、導電助剤、及び項１～４のいずれかに記載の非水電解質二次電池の電極用バインダーを含む、非水電解質二次電池用電極。
項６．　項５に記載の非水電解質二次電池用電極を備える、非水電解質二次電池。
項７．　項６に記載の非水電解質二次電池を備える電気機器。
項８．　（メタ）アクリル酸と、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルとを共重合させたアルキル変性カルボキシル基含有共重合体の、非水電解質二次電池の電極用バインダーとしての使用。
項９．　（メタ）アクリル酸と、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルとを共重合させたアルキル変性カルボキシル基含有共重合体と、活物質と、導電助剤とを含む電極用合剤スラリーを集電体に塗布する工程を備える、非水電解質二次電池用電極の製造方法。 That is, this invention provides the invention of the aspect hung up below.
Item 1. Electrode of non-aqueous electrolyte secondary battery comprising an alkyl-modified carboxyl group-containing copolymer obtained by copolymerizing (meth) acrylic acid and (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms Binder.
Item 2. The term (meth) acrylic acid alkyl ester having 18 to 24 carbon atoms in the alkyl group is copolymerized at a ratio of 0.1 to 10 parts by mass with respect to 100 parts by mass of the (meth) acrylic acid. The binder for electrodes of the nonaqueous electrolyte secondary battery according to 1.
Item 3. Item 3. The nonaqueous electrolyte according to Item 1 or 2, wherein the compound having two or more ethylenically unsaturated groups is copolymerized at a ratio of 0.5 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic acid. Secondary battery electrode binder.
Item 4. Item 4. The compound according to Item 3, wherein the compound having two or more ethylenically unsaturated groups is at least one selected from the group consisting of pentaerythritol allyl ether, diethylene glycol diallyl ether, polyethylene glycol diallyl ether, and polyallyl saccharose. Binder for electrodes of non-aqueous electrolyte secondary batteries.
Item 5. An electrode for a non-aqueous electrolyte secondary battery comprising an active material, a conductive additive, and a binder for an electrode of the non-aqueous electrolyte secondary battery according to any one of Items 1 to 4.
Item 6. A nonaqueous electrolyte secondary battery comprising the electrode for a nonaqueous electrolyte secondary battery according to Item 5.
Item 7. Item 7. An electric device comprising the nonaqueous electrolyte secondary battery according to item 6.
Item 8. For an electrode of a non-aqueous electrolyte secondary battery, an alkyl-modified carboxyl group-containing copolymer obtained by copolymerizing (meth) acrylic acid and a (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms Use as a binder.
Item 9. An alkyl-modified carboxyl group-containing copolymer obtained by copolymerizing (meth) acrylic acid and a (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms, an active material, and a conductive auxiliary agent. The manufacturing method of the electrode for nonaqueous electrolyte secondary batteries provided with the process of apply | coating the electrode mixture slurry containing to a collector.
　本発明の非水電解質二次電池の電極用バインダーは、（メタ）アクリル酸と、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルとを共重合させたアルキル変性カルボキシル基含有共重合体からなり、当該共重合体、活物質、及び導電助剤を含む電極用合剤の集電体からの剥離や活物質の脱離を効果的に抑制することができ、充放電の繰り返しに対しても優れた結着持続性を有する。このため、本発明のバインダーを電極に用いることにより、電池容量が大きく、充放電サイクル特性（電池の寿命特性）に優れた非水電解質二次電池が得られる。 The binder for an electrode of the nonaqueous electrolyte secondary battery of the present invention is an alkyl-modified carboxyl group obtained by copolymerizing (meth) acrylic acid and a (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms. It is possible to effectively suppress the separation of the electrode mixture containing the copolymer, the active material, and the conductive additive from the current collector and the detachment of the active material. It has excellent binding durability even when repeated. Therefore, by using the binder of the present invention for the electrode, a nonaqueous electrolyte secondary battery having a large battery capacity and excellent charge / discharge cycle characteristics (battery life characteristics) can be obtained.
　本発明の非水電解質二次電池の電極用バインダーは、（メタ）アクリル酸と、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルとを共重合させたアルキル変性カルボキシル基含有共重合体からなることを特徴とする。以下、本発明のバインダー、当該バインダーを含む非水電解質二次電池用電極（正極及び負極）、当該電極を用いた非水電解質二次電池、及び当該電池を用いた電気機器について、詳述する。 The binder for an electrode of the nonaqueous electrolyte secondary battery of the present invention is an alkyl-modified carboxyl group obtained by copolymerizing (meth) acrylic acid and a (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms. It consists of a containing copolymer. Hereinafter, the binder of the present invention, electrodes for a non-aqueous electrolyte secondary battery (a positive electrode and a negative electrode) containing the binder, a non-aqueous electrolyte secondary battery using the electrode, and an electric device using the battery will be described in detail. .
＜非水電解質二次電池の電極用バインダー＞
　本発明の非水電解質二次電池の電極用バインダーは、（メタ）アクリル酸と、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルとを共重合させたアルキル変性カルボキシル基含有共重合体からなる。なお、本発明においては、「（メタ）アクリル酸」とは、「アクリル酸及びメタクリル酸」の総称であり、これと類似するものについても同様である。 <Binder for electrode of nonaqueous electrolyte secondary battery>
The binder for an electrode of the nonaqueous electrolyte secondary battery of the present invention is an alkyl-modified carboxyl group obtained by copolymerizing (meth) acrylic acid and a (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms. Containing copolymer. In the present invention, “(meth) acrylic acid” is a general term for “acrylic acid and methacrylic acid”, and the same applies to those similar to this.
　本発明において、（メタ）アクリル酸としては、アクリル酸、β-メチルアクリル酸、メタクリル酸などが挙げられ、アクリル酸、メタクリル酸が好適に用いられる。（メタ）アクリル酸は、１種類単独で使用してもよいし、２種類以上を組み合わせて使用してもよい。 In the present invention, examples of (meth) acrylic acid include acrylic acid, β-methylacrylic acid, and methacrylic acid, and acrylic acid and methacrylic acid are preferably used. (Meth) acrylic acid may be used alone or in combination of two or more.
　本発明において、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルとは、（メタ）アクリル酸と、アルキル基の炭素数が１８～２４である高級アルコールとのエステルをいい、例えば、アクリル酸ステアリル、アクリル酸エイコサニル、アクリル酸ベへニル、アクリル酸テトラコサニル、メタクリル酸ステアリル、メタクリル酸エイコサニル、メタクリル酸ベへニル、メタクリル酸テトラコサニル等が挙げられる。これらの中でも、安価で入手が容易であり、しかも得られる共重合体からなるバインダーの塗工性が優れている観点、及び結着強度の観点から、（メタ）アクリル酸ステアリル、（メタ）アクリル酸エイコサニル、（メタ）アクリル酸ベヘニル、及び（メタ）アクリル酸テトラコサニルが好適に用いられる。なお、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルとしては、例えば日本油脂株式会社製の商品名ブレンマーＶＭＡ７０等の市販品を用いてもよい。アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルは、１種類単独で使用してもよいし、２種類以上を組み合わせて使用してもよい。 In the present invention, the (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms refers to an ester of (meth) acrylic acid and a higher alcohol having an alkyl group having 18 to 24 carbon atoms. Examples include stearyl acrylate, eicosanyl acrylate, behenyl acrylate, tetracosanyl acrylate, stearyl methacrylate, eicosanyl methacrylate, behenyl methacrylate, tetracosanyl methacrylate, and the like. Of these, stearyl (meth) acrylate and (meth) acrylic are inexpensive and easily available, and from the viewpoint of excellent coatability of the binder made of the resulting copolymer, and from the viewpoint of binding strength. Acid eicosanyl, behenyl (meth) acrylate, and tetracosanyl (meth) acrylate are preferably used. In addition, as the (meth) acrylic acid alkyl ester having 18 to 24 carbon atoms in the alkyl group, for example, a commercially available product such as “Blemmer VMA70” manufactured by NOF Corporation may be used. The (meth) acrylic acid alkyl ester having 18 to 24 carbon atoms in the alkyl group may be used alone or in combination of two or more.
　本発明において、アルキル変性カルボキシル基含有共重合体を構成する（メタ）アクリル酸と、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルとの組合せは、それぞれ単独のものを組み合わせてもよいし、どちらか一方または両者について２種以上のものを併用して組み合わせてもよい。 In the present invention, the combination of (meth) acrylic acid constituting the alkyl-modified carboxyl group-containing copolymer and the (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms is independent of each other. They may be combined, or one or both may be used in combination of two or more.
　本発明の非水電解質二次電池の電極用バインダーにおいて、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルの割合としては、特に制限されないが、集電体からの電極用合剤の剥離や活物質の脱離を防ぎ、充放電の繰り返しに対する優れた結着持続性を付与する観点からは、好ましくは、（メタ）アクリル酸１００質量部に対して０．１～１０質量部程度、より好ましくは０．１～５質量部程度、さらに好ましくは１～５質量部程度が挙げられる。アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルの割合が、（メタ）アクリル酸１００質量部に対して０．１質量部未満であると、アルキル基による疎水性相互作用が弱くバインダーとしての結着力が不足する場合がある。一方、１０質量部を超えると、疎水性が強くなり、後述の水などの液状媒体への均一分散が困難となる場合がある。 In the binder for an electrode of the nonaqueous electrolyte secondary battery of the present invention, the proportion of the alkyl group (meth) acrylic acid alkyl ester having 18 to 24 carbon atoms in the alkyl group is not particularly limited, but for the electrode from the current collector From the viewpoint of preventing exfoliation of the mixture and detachment of the active material and imparting excellent binding durability to repeated charge and discharge, preferably 0.1 to 10 parts per 100 parts by weight of (meth) acrylic acid. About 5 parts by mass, more preferably about 0.1 to 5 parts by mass, and still more preferably about 1 to 5 parts by mass. Hydrophobic interaction due to an alkyl group when the ratio of the alkyl group having 18 to 24 carbon atoms in the alkyl group is less than 0.1 parts by mass with respect to 100 parts by mass of (meth) acrylic acid However, the binding force as a binder may be insufficient. On the other hand, if it exceeds 10 parts by mass, the hydrophobicity becomes strong, and it may be difficult to uniformly disperse in a liquid medium such as water described later.
　本発明のバインダーは、集電体からの電極用合剤の剥離や活物質の脱離を効果的に抑制することができ、充放電の繰り返しに対しても優れた結着持続性を有している。このため、高容量で優れた充放電サイクル特性を有する非水電解質二次電池の実現を可能にする。本発明のバインダーがこのような優れた効果を発揮する理由の詳細は、必ずしも明らかではないが、例えば次のように考えることができる。すなわち、本発明のバインダーを構成するアルキル変性カルボキシル基含有共重合体においては、炭素数が１８～２４という長鎖のアルキル基を有する（メタ）アクリル酸アルキルエステルが共重合されている。このため、当該長鎖アルキルエステル部位の分子間引力による会合部が架橋点となり、バインダーを含む電極用合剤スラリーを適度に増粘させ、塗工性が向上していると考えられる。また、当該スラリーの乾燥中において、当該バインダーの長鎖アルキルエステル部位の分子間引力によって、バインダーの偏在が抑制され、活物質の均一分散が保持されるものと考えられる。さらに、本発明のバインダーにおいて、（メタ）アクリル酸アルキルエステルの当該長鎖アルキルエステル部位は、電極中の疎水性が高い導電助剤との親和力が強く、高い結着効果を発現しているものと考えられる。また、共重合体のアルカリ中和により形成される（メタ）アクリル酸の中和塩部位は、カルボキシル基のイオン反発による非晶性によって、活物質を強固に被覆しない、つまり、活物質と電解質との親和性を良好なものとする機能を発現していると推測される。これらの相乗効果によって、本発明のバインダーにおいては、集電体からの電極用合剤の剥離や活物質の脱離を効果的に抑制することができ、充放電の繰り返しに対しても優れた結着持続性を有していると考えられる。さらに、活物質が均一分散されることにより、電極の抵抗が低くなり、電池性能が向上するものと思われる。 The binder of the present invention can effectively suppress the peeling of the electrode mixture from the current collector and the detachment of the active material, and has excellent binding durability against repeated charge and discharge. ing. Therefore, it is possible to realize a non-aqueous electrolyte secondary battery having a high capacity and excellent charge / discharge cycle characteristics. Details of the reason why the binder of the present invention exhibits such excellent effects are not necessarily clear, but can be considered as follows, for example. That is, in the alkyl-modified carboxyl group-containing copolymer constituting the binder of the present invention, a (meth) acrylic acid alkyl ester having a long-chain alkyl group having 18 to 24 carbon atoms is copolymerized. For this reason, it is thought that the association part by the intermolecular attractive force of the said long-chain alkyl ester site | part becomes a crosslinking point, thickens the mixture slurry for electrodes containing a binder moderately, and is improving the coating property. Further, during the drying of the slurry, it is considered that the uneven distribution of the binder is suppressed and the uniform dispersion of the active material is maintained by the intermolecular attractive force of the long-chain alkyl ester portion of the binder. Furthermore, in the binder of the present invention, the long-chain alkyl ester portion of the (meth) acrylic acid alkyl ester has a strong affinity for the conductive assistant with high hydrophobicity in the electrode and exhibits a high binding effect. it is conceivable that. In addition, the neutralized salt portion of (meth) acrylic acid formed by alkali neutralization of the copolymer does not firmly cover the active material due to the amorphous nature due to ion repulsion of the carboxyl group, that is, the active material and the electrolyte It is presumed that a function to improve the affinity with is expressed. By these synergistic effects, in the binder of the present invention, it is possible to effectively suppress the peeling of the electrode mixture from the current collector and the detachment of the active material, and it is excellent for repeated charge and discharge. It is thought that it has binding durability. Further, it is considered that the active material is uniformly dispersed to reduce the resistance of the electrode and improve the battery performance.
　本発明の非水電解質二次電池の電極用バインダーにおいては、上記の（メタ）アクリル酸と、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルに加えて、さらにエチレン性不飽和基を２個以上有する化合物が共重合されていてもよい。エチレン性不飽和基を２個以上有する化合物としては、特に制限されないが、集電体からの電極用合剤の剥離や活物質の脱離を防ぎ、充放電の繰り返しに対する優れた結着持続性を付与する観点からは、エチレン性不飽和基がアリル基である化合物が好ましい。さらに、これらの中でも、活物質、炭素繊維などの導電助剤、アルミや銅などの集電体との結着性を高める観点からは、ペンタエリトリトールジアリルエーテル、ペンタエリトリトールトリアリルエーテル、ペンタエリトリトールテトラアリルエーテル等のペンタエリトリトールアリルエーテルや、ジエチレングリコールジアリルエーテル、ポリエチレングリコールジアリルエーテル、及びポリアリルサッカロースなどがさらに好ましい。なお、これらエチレン性不飽和基を２個以上有する化合物は、それぞれ単独で、あるいは２種以上を併用してもよい。 In the binder for an electrode of the non-aqueous electrolyte secondary battery of the present invention, in addition to the above (meth) acrylic acid and the (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms, further ethylenic A compound having two or more unsaturated groups may be copolymerized. Although it does not restrict | limit especially as a compound which has two or more ethylenically unsaturated groups, The peeling of the electrode mixture from an electrical power collector and the detachment | desorption of an active material are prevented, and the outstanding binding persistence with respect to the repetition of charging / discharging. From the viewpoint of imparting the above, a compound in which the ethylenically unsaturated group is an allyl group is preferable. Furthermore, among these, from the viewpoint of improving the binding properties with active materials, conductive assistants such as carbon fibers, and current collectors such as aluminum and copper, pentaerythritol diallyl ether, pentaerythritol triallyl ether, pentaerythritol tetra More preferred are pentaerythritol allyl ether such as allyl ether, diethylene glycol diallyl ether, polyethylene glycol diallyl ether, and polyallyl saccharose. In addition, these compounds having two or more ethylenically unsaturated groups may be used alone or in combination of two or more.
　本発明において、エチレン性不飽和基を２個以上有する化合物を使用する場合の割合としては、（メタ）アクリル酸１００質量部に対して０．５質量部以下、好ましくは０．００１～０．５質量部程度、より好ましくは０．０１～０．２質量部程度が挙げられる。エチレン性不飽和基を２個以上有する化合物の割合が０．５質量部以下であれば、バインダーを含む電極用合剤スラリーが均一となり、電池性能が低下するおそれがない。 In the present invention, the ratio in the case of using a compound having two or more ethylenically unsaturated groups is 0.5 parts by mass or less, preferably 0.001 to 0.005 parts per 100 parts by mass of (meth) acrylic acid. About 5 parts by mass, more preferably about 0.01 to 0.2 parts by mass. If the ratio of the compound which has 2 or more of ethylenically unsaturated groups is 0.5 mass part or less, the electrode mixture slurry containing a binder will become uniform and there is no possibility that battery performance may fall.
　本発明のバインダーを構成するアルキル変性カルボキシル基含有共重合体の重量平均分子量としては、特に制限されないが、例えば、１０,０００～１０,０００,０００程度が挙げられる。なお、重量平均分子量は、標準ポリスチレンスチレンを用いたゲルパーミエーションクロマトグラフィー（ＧＰＣ）で測定して得られた値である。 The weight average molecular weight of the alkyl-modified carboxyl group-containing copolymer constituting the binder of the present invention is not particularly limited, and examples thereof include about 10,000 to 10,000,000. The weight average molecular weight is a value obtained by measurement by gel permeation chromatography (GPC) using standard polystyrene styrene.
　本発明において、（メタ）アクリル酸と、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルと、必要に応じて使用されるエチレン性不飽和基を２個以上有する化合物とを共重合させてアルキル変性カルボキシル基含有共重合体を得る方法としては、特に限定されず、これらの原料を不活性ガス雰囲気下、溶媒中で攪拌し、重合開始剤を用いて重合させる方法等の通常の方法を用いることができる。重合方法としては、特に制限されず、通常の乳化重合、懸濁重合、分散重合、溶液重合、沈殿重合などを用いることができ、好ましくは乳化重合、懸濁重合、分散重合、沈殿重合を用いることができる。不活性ガスとしては、例えば、窒素ガス、アルゴンガス等が挙げられる。 In the present invention, (meth) acrylic acid, a (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms, a compound having two or more ethylenically unsaturated groups used as necessary, The method for obtaining an alkyl-modified carboxyl group-containing copolymer by copolymerizing is not particularly limited, and these raw materials are stirred in a solvent in an inert gas atmosphere and polymerized using a polymerization initiator, etc. The usual method can be used. The polymerization method is not particularly limited, and usual emulsion polymerization, suspension polymerization, dispersion polymerization, solution polymerization, precipitation polymerization and the like can be used, and preferably emulsion polymerization, suspension polymerization, dispersion polymerization, precipitation polymerization are used. be able to. Examples of the inert gas include nitrogen gas and argon gas.
　また、共重合に用いる溶媒としては、（メタ）アクリル酸、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステル、及び必要に応じて使用されるエチレン性不飽和基を２個以上有する化合物を溶解するが、共重合によって生成するアルキル変性カルボキシル基含有共重合体を溶解しないものであって、当該反応を阻害しないものであれば特に限定されない。溶媒の具体例としては、ノルマルペンタン、ノルマルヘキサン、イソヘキサン、ノルマルヘプタン、ノルマルオクタン、イソオクタン等の鎖状炭化水素；シクロペンタン、メチルシクロペンタン、シクロヘキサン、メチルシクロヘキサン等の脂環式炭化水素；ベンゼン、トルエン、キシレン、クロロベンゼン等の芳香族炭化水素；エチレンジクロライド等のハロゲン化炭化水素；酢酸エチル、酢酸イソプロピル等のエステル類；メチルエチルケトン、メチルイソブチルケトン等のケトン類等が挙げられる。溶媒は、１種類単独で使用してもよいし、２種類以上を組み合わせて使用してもよい。 Further, as a solvent used for copolymerization, (meth) acrylic acid, (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms, and ethylenically unsaturated group to be used as needed are used. The compound having at least one is dissolved, but is not particularly limited as long as it does not dissolve the alkyl-modified carboxyl group-containing copolymer produced by copolymerization and does not inhibit the reaction. Specific examples of the solvent include chain hydrocarbons such as normal pentane, normal hexane, isohexane, normal heptane, normal octane and isooctane; alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane and methylcyclohexane; benzene, Aromatic hydrocarbons such as toluene, xylene and chlorobenzene; halogenated hydrocarbons such as ethylene dichloride; esters such as ethyl acetate and isopropyl acetate; ketones such as methyl ethyl ketone and methyl isobutyl ketone. A solvent may be used individually by 1 type and may be used in combination of 2 or more type.
　共重合に用いる重合開始剤としては、特に限定されないが、ラジカル重合開始剤が好適に用いられ、例えば、α，α’－アゾイソブチロニトリル、２，２’－アゾビス－２，４－ジメチルバレロニトリル、２，２’－アゾビスメチルイソブチレート、過酸化ベンゾイル、ラウロイルパーオキサイド、クメンハイドロパーオキサイド、第三級ブチルハイドロパーオキサイド等が挙げられる。中でも、取り扱いやすく、安定性に優れている観点から、２，２’－アゾビスメチルイソブチレートが好ましい。 The polymerization initiator used for the copolymerization is not particularly limited, but a radical polymerization initiator is preferably used. For example, α, α′-azoisobutyronitrile, 2,2′-azobis-2,4-dimethyl is used. Examples include valeronitrile, 2,2′-azobismethylisobutyrate, benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, and tertiary butyl hydroperoxide. Among these, 2,2'-azobismethylisobutyrate is preferable from the viewpoint of easy handling and excellent stability.
　重合開始剤の使用量としては、特に制限されないが、例えば（メタ）アクリル酸１モルに対して０．００００３～０．００２モル程度であることが望ましい。重合開始剤の使用量が０．００００３モル未満の場合、反応速度が遅くなるため経済的でなくなる場合がある。また、重合開始剤の使用量が０．００２モルを超える場合、重合が急激に進行するため除熱が困難となり、反応の制御が難しくなる場合がある。 The amount of the polymerization initiator used is not particularly limited, but is preferably about 0.00003 to 0.002 mol per 1 mol of (meth) acrylic acid, for example. When the amount of the polymerization initiator used is less than 0.00003 mol, the reaction rate becomes slow, which may not be economical. Moreover, when the usage-amount of a polymerization initiator exceeds 0.002 mol, since superposition | polymerization advances rapidly, heat removal becomes difficult and control of reaction may become difficult.
　反応温度としては、特に制限されないが、好ましくは５０～９０℃程度、より好ましくは５５℃～７５℃程度が挙げられる。反応温度が５０℃未満である場合、反応溶液の粘度が上昇し、均一に攪拌することができなくなる場合がある。また、反応温度が９０℃を超える場合、反応が急激に進行し、反応の制御ができなくなる場合がある。反応時間は、反応温度によって異なるので一概には決定することができないが、通常、０．５～５時間程度である。 The reaction temperature is not particularly limited, but is preferably about 50 to 90 ° C, more preferably about 55 to 75 ° C. When the reaction temperature is less than 50 ° C., the viscosity of the reaction solution increases, and it may not be possible to stir uniformly. Moreover, when reaction temperature exceeds 90 degreeC, reaction advances rapidly and reaction control may become impossible. The reaction time varies depending on the reaction temperature and cannot be determined unconditionally, but is usually about 0.5 to 5 hours.
　反応終了後、反応溶液を例えば８０～１３０℃程度に加熱し、溶媒を留去することにより、アルキル変性カルボキシル基含有共重合体を得ることができる。加熱温度が８０℃未満の場合、乾燥に長時間を要する場合がある。また、加熱温度が１３０℃を超える場合、得られるアルキル変性カルボキシル基含有共重合体の水などの液状媒体への溶解性が悪化する場合がある。 After completion of the reaction, the reaction solution is heated to about 80 to 130 ° C., for example, and the solvent is distilled off to obtain an alkyl-modified carboxyl group-containing copolymer. When the heating temperature is less than 80 ° C., drying may take a long time. Moreover, when heating temperature exceeds 130 degreeC, the solubility to liquid media, such as water, of the alkyl-modified carboxyl group-containing copolymer obtained may deteriorate.
　かくして得られるアルキル変性カルボキシル基含有共重合体の体積平均粒子径としては、特に制限されないが、０．１～５０μｍ程度であることが好ましく、０．５～３０μｍ程度であることがより好ましく、１～２０μｍ程度であることがさらに好ましい。体積平均粒子径が０．１μｍ未満であると、電極中において、活物質を十分結着するために必要なバインダー量が多くなり、その結果、バインダーが活物質の表面を被覆してレート特性が低下する場合がある。逆に、共重合体の体積平均粒子径が５０μｍを超えると、導電助剤の分散が不均一となり抵抗が大きくなる可能性がある。なお、これら粒子は加水等により凝集させることができ、その場合、体積平均粒子径が１００～１０００μｍとなってもよい。なお、アルキル変性カルボキシル基含有共重合体の体積平均粒子径は、レーザー回折式粒度分布測定装置（島津製作所社製ＳＡＬＤ－７１００）にて分散剤としてノルマルヘキサンを用いることによって測定して得られた値である。 The volume average particle size of the alkyl-modified carboxyl group-containing copolymer thus obtained is not particularly limited, but is preferably about 0.1 to 50 μm, more preferably about 0.5 to 30 μm. More preferably, it is about ˜20 μm. When the volume average particle diameter is less than 0.1 μm, the amount of binder necessary for sufficiently binding the active material in the electrode increases, and as a result, the binder coats the surface of the active material, resulting in rate characteristics. May decrease. On the other hand, when the volume average particle diameter of the copolymer exceeds 50 μm, there is a possibility that the dispersion of the conductive auxiliary agent becomes non-uniform and resistance increases. These particles can be aggregated by addition of water or the like, and in that case, the volume average particle diameter may be 100 to 1000 μm. The volume average particle size of the alkyl-modified carboxyl group-containing copolymer was measured by using normal hexane as a dispersant with a laser diffraction particle size distribution analyzer (SALD-7100 manufactured by Shimadzu Corporation). Value.
　本発明のアルキル変性カルボキシル基含有共重合体からなるバインダーを電極に用いる場合、通常、後述する水などの液状媒体に溶解または分散させて用いられる。 When the binder comprising the alkyl-modified carboxyl group-containing copolymer of the present invention is used for an electrode, it is usually used by being dissolved or dispersed in a liquid medium such as water described later.
＜正極＞
　上記のとおり、本発明の非水電解質二次電池の電極用バインダーは、集電体からの電極用合剤の剥離や活物質の脱離を効果的に抑制することができ、充放電の繰り返しに対しても優れた結着持続性を有する。このため、本発明のバインダーを正極に用いることにより、電池容量が大きく、充放電サイクル特性に優れた非水電解質二次電池が得られる。 <Positive electrode>
As described above, the binder for an electrode of the nonaqueous electrolyte secondary battery of the present invention can effectively suppress the peeling of the electrode mixture from the current collector and the detachment of the active material, and repeated charge and discharge. In addition, it has excellent binding durability. Therefore, by using the binder of the present invention for the positive electrode, a nonaqueous electrolyte secondary battery having a large battery capacity and excellent charge / discharge cycle characteristics can be obtained.
　本発明における正極は、例えば次のようにして製造されるものである。正極活物質、導電助剤、本発明のバインダー、水などの液状媒体を混合してペースト状のスラリーを正極合剤とする。この正極合剤を正極集電体に塗布することによって、本発明の非水電解質二次電池用正極とすることができる。本発明のバインダーは、予め液状媒体に溶かして用いてもよいし、粉末状の本発明のバインダーと正極活物質とを予め混合し、その後に液状媒体を加えて用いてもよい。 The positive electrode in the present invention is manufactured, for example, as follows. A positive electrode active material, a conductive additive, a binder of the present invention, and a liquid medium such as water are mixed to form a paste slurry as a positive electrode mixture. By applying this positive electrode mixture to the positive electrode current collector, the positive electrode for a non-aqueous electrolyte secondary battery of the present invention can be obtained. The binder of the present invention may be used by dissolving in a liquid medium in advance, or the powdered binder of the present invention and a positive electrode active material may be mixed in advance, and then the liquid medium may be added and used.
（正極活物質）
　正極活物質としては、特に制限されず、非水電解質二次電池で使用される公知の正極活物質が使用できる。正極活物質の具体例としては、リン酸鉄リチウム（ＬｉＦｅＰＯ4）、リン酸マンガンリチウム（ＬｉＭｎＰＯ4）、リン酸コバルトリチウム（ＬｉＣｏＰＯ4）、ピロリン酸鉄（Ｌｉ2ＦｅＰ2Ｏ7）、コバルト酸リチウム複合酸化物（ＬｉＣｏＯ2）、スピネル型マンガン酸リチウム複合酸化物（ＬｉＭｎ2Ｏ4）、マンガン酸リチウム複合酸化物（ＬｉＭｎＯ2）、ニッケル酸リチウム複合酸化物（ＬｉＮｉＯ2）、ニオブ酸リチウム複合酸化物（ＬｉＮｂＯ2）、鉄酸リチウム複合酸化物（ＬｉＦｅＯ2）、マグネシウム酸リチウム複合酸化物（ＬｉＭｇＯ2）、カルシウム酸リチウム複合酸化物（ＬｉＣａＯ2）、銅酸リチウム複合酸化物（ＬｉＣｕＯ2）、亜鉛酸リチウム複合酸化物（ＬｉＺｎＯ2）、モリブデン酸リチウム複合酸化物（ＬｉＭｏＯ2）、タンタル酸リチウム複合酸化物（ＬｉＴａＯ2）、タングステン酸リチウム複合酸化物（ＬｉＷＯ2）、リチウム－ニッケル－コバルト－アルミニウム複合酸化物（ＬｉＮｉ0.8Ｃｏ0.15Ａｌ0.05Ｏ2）、リチウム－ニッケル－コバルト－マンガン複合酸化物（ＬｉＮｉ0.33Ｃｏ0.33Ｍｎ0.33Ｏ2）、Ｌｉ過剰系ニッケル－コバルト－マンガン複合酸化物、酸化マンガンニッケル（ＬｉＮｉ0.5Ｍｎ1.5Ｏ4）、酸化マンガン（ＭｎＯ2）、バナジウム系酸化物、硫黄系酸化物、シリケート系酸化物などが挙げられる。正極活物質は、１種類単独で使用してもよいし、２種類以上を組み合わせて使用してもよい。 (Positive electrode active material)
It does not restrict | limit especially as a positive electrode active material, The well-known positive electrode active material used with a nonaqueous electrolyte secondary battery can be used. Specific examples of the positive electrode active material include lithium iron phosphate (LiFePO 4 ), lithium manganese phosphate (LiMnPO 4 ), lithium cobalt phosphate (LiCoPO 4 ), iron pyrophosphate (Li 2 FeP 2 O 7 ), cobalt acid Lithium composite oxide (LiCoO 2 ), spinel type lithium manganate composite oxide (LiMn 2 O 4 ), lithium manganate composite oxide (LiMnO 2 ), lithium nickelate composite oxide (LiNiO 2 ), lithium niobate composite oxide (LiNbO 2), ferrate lithium composite oxide (LiFeO 2), lithium magnesium acid complex oxide (LiMgO 2), lithium composite oxide of calcium acid (LiCaO 2), cuprate lithium composite oxide (LiCuO 2) , lithium composite oxide zincate (LiZnO 2), lithium molybdate double Oxide (LiMoO 2), lithium tantalate complex oxide (LiTaO 2), tungstic acid lithium composite oxide (LiWO 2), lithium - nickel - cobalt - aluminum composite oxide (LiNi 0.8 Co 0.15 Al 0.05 O 2), Lithium-nickel-cobalt-manganese composite oxide (LiNi 0.33 Co 0.33 Mn 0.33 O 2 ), Li-rich nickel-cobalt-manganese composite oxide, manganese nickel oxide (LiNi 0.5 Mn 1.5 O 4 ), manganese oxide (MnO 2 ), Vanadium oxides, sulfur oxides, silicate oxides, and the like. A positive electrode active material may be used individually by 1 type, and may be used in combination of 2 or more types.
（導電助剤）
　導電助剤は、導電性を有していれば、特に制限されないが、炭素粉末が好ましい。炭素粉末としては、通常用いられているもの、例えば、アセチレンブラック（ＡＢ）、ケッチェンブラック（ＫＢ）、黒鉛、カーボンファイバー、カーボンチューブ、グラフェン、非晶質炭素、ハードカーボン、ソフトカーボン、グラッシーカーボン、カーボンナノファイバー、カーボンナノチューブ等の炭素材料が挙げられる。導電助剤は、１種類単独で使用してもよいし、２種類以上を組み合わせて使用してもよい。 (Conductive aid)
The conductive auxiliary agent is not particularly limited as long as it has conductivity, but carbon powder is preferable. As carbon powder, those commonly used, for example, acetylene black (AB), ketjen black (KB), graphite, carbon fiber, carbon tube, graphene, amorphous carbon, hard carbon, soft carbon, glassy carbon And carbon materials such as carbon nanofibers and carbon nanotubes. A conductive support agent may be used individually by 1 type, and may be used in combination of 2 or more types.
　導電助剤としては、これらの中でも導電性向上の観点から、カーボンナノファイバー及びカーボンナノチューブが好ましく、カーボンナノチューブがより好ましい。導電助剤としてカーボンナノチューブを使用する場合、その使用量については、特に制限されないが、例えば、導電助剤全体の３０～１００質量％程度が好ましく、４０～１００質量％程度がより好ましい。カーボンナノチューブの使用量が３０質量％未満では正極活物質と正極集電体の間に十分な導電経路が確保されず、特に高速充放電において十分な導電経路を形成することができない場合がある。なお、カーボンナノファイバーとは、太さが数ｎｍ～数百ｎｍの繊維状材料をいい、中空構造を有するものを特にカーボンナノチューブという。カーボンナノチューブには、単層カーボンナノチューブ、多層カーボンナノチューブなどの種類がある。これらは気相成長法、アーク放電法、レーザー蒸発法などの種々方法により製造されるが、製造方法は特に制限されない。 Among these, carbon nanofibers and carbon nanotubes are preferable from the viewpoint of improving conductivity, and carbon nanotubes are more preferable. When carbon nanotubes are used as the conductive additive, the amount used is not particularly limited, but is preferably about 30 to 100% by mass, and more preferably about 40 to 100% by mass of the total conductive auxiliary. When the amount of carbon nanotube used is less than 30% by mass, a sufficient conductive path is not ensured between the positive electrode active material and the positive electrode current collector, and a sufficient conductive path may not be formed particularly in high-speed charge / discharge. Carbon nanofiber refers to a fibrous material having a thickness of several nanometers to several hundred nanometers, and one having a hollow structure is particularly referred to as a carbon nanotube. There are various types of carbon nanotubes such as single-walled carbon nanotubes and multi-walled carbon nanotubes. These are produced by various methods such as a vapor phase growth method, an arc discharge method, and a laser evaporation method, but the production method is not particularly limited.
　正極における導電助剤の使用量については、特に制限されないが、例えば、正極活物質、導電助剤、及びバインダーの合計を１００質量％とした場合、好ましくは１．５～２０質量％程度、より好ましくは２．０～１０質量％程度が挙げられる。なお、導電助剤の使用量が１．５質量％未満であると、正極の導電性を十分に向上させることができない場合がある。また、導電助剤の使用量が２０質量％を超えると、正極活物質の割合が相対的に減少するため、電池の充放電時に高容量が得られにくいこと、液状媒体として水を用いる場合には、導電助剤の炭素粉末が水を弾くため均一分散することが難しく正極活物質の凝集を招くこと、正極活物質と比較して小さいため表面積が大きくなり使用するバインダーの量が増えることなどの点で好ましくない。 The amount of the conductive auxiliary used in the positive electrode is not particularly limited. For example, when the total amount of the positive electrode active material, the conductive auxiliary, and the binder is 100% by mass, it is preferably about 1.5 to 20% by mass. Preferably, it is about 2.0 to 10% by mass. In addition, the electroconductivity of a positive electrode may not fully be improved as the usage-amount of a conductive support agent is less than 1.5 mass%. In addition, when the amount of the conductive auxiliary agent used exceeds 20% by mass, the ratio of the positive electrode active material is relatively reduced. Therefore, it is difficult to obtain a high capacity during charge / discharge of the battery, and when water is used as the liquid medium. Is difficult to uniformly disperse because the carbon powder of the conductive auxiliary agent repels water, causing aggregation of the positive electrode active material, and because it is small compared to the positive electrode active material, the surface area increases and the amount of binder used increases. This is not preferable.
　正極における本発明のバインダーの使用量については、特に制限されないが、例えば、正極活物質、導電助剤、及びバインダーの合計を１００質量％とした場合、好ましくは０．５質量％以上３０質量％以下、より好ましくは１質量％以上２０質量％以下、さらに好ましくは２質量％以上８質量％以下が挙げられる。バインダーが多すぎると正極の電極内抵抗が大きくなり高率放電特性の悪化を招く場合がある。また、バインダーが少なすぎると充放電サイクル特性が低下する場合がある。 The amount of the binder of the present invention used in the positive electrode is not particularly limited. For example, when the total amount of the positive electrode active material, the conductive additive, and the binder is 100% by mass, preferably 0.5% by mass to 30% by mass. Hereinafter, more preferably, it is 1 mass% or more and 20 mass% or less, More preferably, 2 mass% or more and 8 mass% or less are mentioned. If the amount of the binder is too large, the resistance in the electrode of the positive electrode may increase and the high rate discharge characteristics may be deteriorated. Moreover, when there are too few binders, a charge / discharge cycle characteristic may fall.
（液状媒体）
　液状媒体としては、水や、非水系媒体が挙げられる。非水系媒体としては、例えば、ｎ－オクタン、イソオクタン、ノナン、デカン、デカリン、ピネン、クロロドデカンなどの脂肪族炭化水素類； シクロペンタン、シクロヘキサン、シクロヘプタン、メチルシクロペンタンなどの環状脂肪族炭化水素類； スチレン、クロロベンゼン、クロロトルエン、エチルベンゼン、ジイソプロピルベンゼン、クメンなどの芳香族炭化水素類； メタノール、エタノール、プロパノール、イソプロパノール、ブタノール、ベンジルアルコール、グリセリンなどのアルコール類； アセトン、メチルエチルケトン、シクロペンタノン、イソホロンなどのケトン類； メチルエチルエーテル、ジエチルエーテル、テトラヒドロフラン、ジオキサンなどのエーテル類； γ－ブチロラクトン、δ－ブチロラクトンなどのラクトン類；β－ラクタムなどのラクタム類； ジメチルホルムアミド、Ｎ－メチルピロリドン、ジメチルアセトアミドなどの鎖状・環状のアミド類； メチレンシアノヒドリン、エチレンシアノヒドリン、３，３'－チオジプロピオニトリル、アセトニトリルなどのニトリル基含有化合物類； ピリジン、ピロールなどの含窒素複素環系化合物；エチレングリコール、プロピレングリコールなどのグリコール類； ジエチレングリコール、ジエチレングリコールモノエチルエーテル、ジエチレングリコールエチルブチルエーテルなどのジエチレングリコール類； ギ酸エチル、乳酸エチル、乳酸プロピル、安息香酸メチル、酢酸メチル、アクリル酸メチルなどのエステル類などが例示される。また、非水系媒体としては、ラッカー、ガソリン、ナフサ、ケロシンなどの混合物を用いることができる。上記液状媒体の中でも溶解性及び経済性の観点から水が好ましく、水酸化ナトリウム等のアルカリ成分を用いて溶液のｐＨを６～８に調整して用いるのが好ましい。 (Liquid medium)
Examples of the liquid medium include water and non-aqueous media. Examples of non-aqueous media include aliphatic hydrocarbons such as n-octane, isooctane, nonane, decane, decalin, pinene, and chlorododecane; and cyclic aliphatic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane, and methylcyclopentane. Aromatic hydrocarbons such as styrene, chlorobenzene, chlorotoluene, ethylbenzene, diisopropylbenzene, cumene; alcohols such as methanol, ethanol, propanol, isopropanol, butanol, benzyl alcohol, glycerin; acetone, methyl ethyl ketone, cyclopentanone, Ketones such as isophorone; ethers such as methyl ethyl ether, diethyl ether, tetrahydrofuran and dioxane; and lacquers such as γ-butyrolactone and δ-butyrolactone Tons; Lactams such as β-lactam; Chain and cyclic amides such as dimethylformamide, N-methylpyrrolidone and dimethylacetamide; Methylene cyanohydrin, ethylene cyanohydrin, 3,3′-thiodipropionitrile, acetonitrile, etc. Nitrile group-containing compounds; nitrogen-containing heterocyclic compounds such as pyridine and pyrrole; glycols such as ethylene glycol and propylene glycol; diethylene glycols such as diethylene glycol, diethylene glycol monoethyl ether, and diethylene glycol ethyl butyl ether; ethyl formate, ethyl lactate, and lactic acid Examples include esters such as propyl, methyl benzoate, methyl acetate, and methyl acrylate. As the non-aqueous medium, a mixture of lacquer, gasoline, naphtha, kerosene, etc. can be used. Among the above liquid media, water is preferable from the viewpoint of solubility and economy, and it is preferable to adjust the pH of the solution to 6 to 8 using an alkali component such as sodium hydroxide.
　本発明のアルキル変性カルボキシル基含有共重合体からなるバインダーを、液状媒体に溶解または分散させて用いる場合、溶解液又は分散液全体における当該共重合体の含有量としては、好ましくは０．２～７０質量％程度、より好ましくは０．５～６０質量％程度、さらに好ましくは０．５～５０質量％程度、特に好ましくは２～３５質量％程度が挙げられる。 When the binder comprising the alkyl-modified carboxyl group-containing copolymer of the present invention is used after being dissolved or dispersed in a liquid medium, the content of the copolymer in the entire solution or dispersion is preferably 0.2 to About 70% by mass, more preferably about 0.5 to 60% by mass, still more preferably about 0.5 to 50% by mass, and particularly preferably about 2 to 35% by mass.
　スラリーのｐＨは４～１０が好ましく、ｐＨ５～９がより好ましく、ｐＨ６～８がさらに好ましい。ｐＨが４以下になると、正極集電体の腐食や、電解液、正極活物質の劣化などによる電池性能が低下する恐れがある。また、ｐＨが１０以上になると、アルミニウムなどの金属により構成される正極集電体が腐食され、電池性能が低下する恐れがある。 The pH of the slurry is preferably 4 to 10, more preferably 5 to 9, and still more preferably 6 to 8. When the pH is 4 or less, battery performance may be deteriorated due to corrosion of the positive electrode current collector, deterioration of the electrolytic solution, or the positive electrode active material. On the other hand, when the pH is 10 or more, the positive electrode current collector composed of a metal such as aluminum is corroded, and the battery performance may be deteriorated.
　スラリーのｐＨを調整することを目的として、ｐＨ調整剤を用いてもよい。ｐＨ調整剤としては、ｐＨの酸調整剤、ｐＨのアルカリ調整剤が挙げられる。ｐＨの酸調整剤としては、例えば、塩酸、硫酸、りん酸、硝酸などの無機酸類；ギ酸、酢酸、プロピオン酸、クエン酸などの有機酸類が挙げられる。また、ｐＨのアルカリ調整剤としては、例えば、水酸化ナトリウム、水酸化カリウム、水酸化リチウムなどの無機アルカリ類；アンモニア、メチルアミン、エチルアミンなどの有機アルカリ類などが挙げられる。 A pH adjusting agent may be used for the purpose of adjusting the pH of the slurry. Examples of the pH adjuster include a pH acid adjuster and a pH alkali adjuster. Examples of the pH acid adjusting agent include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid; and organic acids such as formic acid, acetic acid, propionic acid, and citric acid. Examples of the pH adjusting agent include inorganic alkalis such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; organic alkalis such as ammonia, methylamine, and ethylamine.
　また、本発明においては、スラリーの塗工性を向上させたり、充放電特性を向上させるために添加剤を用いてもよい。これらの添加剤としては、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などのセルロース系ポリマー、ポリアクリル酸ナトリウムなどのポリアクリル酸塩、ポリビニルアルコール、ポリエチレンオキシド、ポリビニルピロリドン、（メタ）アクリル酸－ビニルアルコール共重合体、マレイン酸－ビニルアルコール共重合体、変性ポリビニルアルコール、ポリエチレングリコール、エチレン－ビニルアルコール共重合体、ポリ酢酸ビニル部分ケン化物などが挙げられる。添加剤は、１種類単独で使用してもよいし、２種類以上を組み合わせて使用してもよい。 In the present invention, an additive may be used to improve the coating property of the slurry or improve the charge / discharge characteristics. Examples of these additives include cellulose polymers such as carboxymethylcellulose, methylcellulose, and hydroxypropylcellulose, polyacrylates such as sodium polyacrylate, polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, and (meth) acrylic acid-vinyl. Examples thereof include alcohol copolymers, maleic acid-vinyl alcohol copolymers, modified polyvinyl alcohol, polyethylene glycol, ethylene-vinyl alcohol copolymers, and polyvinyl acetate partially saponified products. An additive may be used individually by 1 type and may be used in combination of 2 or more types.
　これらの添加剤の使用割合としては、特に制限されないが、バインダーを構成するアルキル変性カルボキシル基含有共重合体１００質量部に対して、好ましくは３００質量部未満、より好ましくは３０質量部以上２５０質量部以下、さらに好ましくは４０質量部以上２００質量部以下が挙げられる。このような範囲であれば、平滑性が優れた電極を得ることができる。なお、このような添加剤は、バインダー組成物に添加して用いてもよいし、上記のスラリーに添加して用いてもよい。 The use ratio of these additives is not particularly limited, but is preferably less than 300 parts by weight, more preferably 30 parts by weight or more and 250 parts by weight with respect to 100 parts by weight of the alkyl-modified carboxyl group-containing copolymer constituting the binder. Part or less, more preferably 40 parts by mass or more and 200 parts by mass or less. If it is such a range, the electrode excellent in smoothness can be obtained. Such additives may be used by adding to the binder composition, or may be used by adding to the above slurry.
　なお、正極において、本発明の目的を阻害しない範囲であれば、本発明のバインダー加えて、アクリル酸、アクリル酸金属中和塩、メタクリル酸、メタクリル酸金属中和塩、カルボキシルメチルセルロース、ヒドロキシエチルセルロースなどの水溶性化合物や、スチレンブタジエン共重合体含有エマルジョン、ブタジエンアクリロニトリル共重合体含有エマルジョン、ＰＶｄＦ含有エマルジョン、ポリテトラフルオロエタン重合体含有エマルジョンなどの従来のバインダーを併用してもよい。 In addition, in the positive electrode, as long as the object of the present invention is not impaired, acrylic acid, acrylic acid metal neutralized salt, methacrylic acid, metal methacrylate neutralized salt, carboxymethyl cellulose, hydroxyethyl cellulose, etc. A conventional binder such as a water-soluble compound, a styrene-butadiene copolymer-containing emulsion, a butadiene acrylonitrile copolymer-containing emulsion, a PVdF-containing emulsion, or a polytetrafluoroethane polymer-containing emulsion may be used in combination.
（正極集電体）
　正極集電体の材料は、電子伝導性を有し、保持した正極材料に通電し得るものであれば、特に制限されない。正極集電体の材料としては、例えば、Ｃ、Ｔｉ、Ｃｒ、Ｍｏ、Ｒｕ、Ｒｈ、Ｔａ、Ｗ、Ｏｓ、Ｉｒ、Ｐｔ、Ａｕ、Ａｌ等の導電性物質、これら導電性物質の二種類以上を含有する合金（例えば、ステンレス鋼）などが挙げられる。電気伝導性が高く、電解液中の安定性と耐酸化性がよい観点から、正極集電体の材料としてはＣ、Ａｌ、ステンレス鋼等が好ましく、さらに材料コストの観点からＡｌ等が好ましい。 (Positive electrode current collector)
The material of the positive electrode current collector is not particularly limited as long as it has electronic conductivity and can supply current to the held positive electrode material. Examples of the material for the positive electrode current collector include conductive substances such as C, Ti, Cr, Mo, Ru, Rh, Ta, W, Os, Ir, Pt, Au, and Al, and two or more kinds of these conductive substances. An alloy containing, for example, stainless steel. From the viewpoint of high electrical conductivity, good stability in the electrolytic solution, and good oxidation resistance, the material of the positive electrode current collector is preferably C, Al, stainless steel or the like, and more preferably Al or the like from the viewpoint of material cost.
　正極集電体の形状としては、特に制限されないが、例えば、箔状、三次元形状などが挙げられる。なお、三次元形状（発泡メタル、メッシュ、織布、不織布、エキスパンド等）とすると、正極集電体との密着性が低いバインダーであっても高い容量密度の電極が得られ、高率充放電特性も良好になる。 The shape of the positive electrode current collector is not particularly limited, and examples thereof include a foil shape and a three-dimensional shape. In addition, when a three-dimensional shape (foamed metal, mesh, woven fabric, non-woven fabric, expanded, etc.) is used, a high capacity density electrode can be obtained even with a binder having low adhesion to the positive electrode current collector, and high rate charge / discharge The characteristics are also good.
　なお、箔状の正極集電体であっても、予め集電体表面上にプライマー層を形成することにより高容量化を図ることができる。プライマー層としては、正極活物質層と正極集電体との密着性が良好で、かつ、導電性を有しているものを用いることができる。例えば、炭素系導電助剤を混ぜ合わせたバインダーを正極集電体上に０．１μｍ～５０μｍの厚みで塗布することでプライマー層を形成できる。 In addition, even if it is a foil-shaped positive electrode electrical power collector, high capacity | capacitance can be achieved by forming a primer layer on the electrical power collector surface previously. As the primer layer, a layer having good adhesion between the positive electrode active material layer and the positive electrode current collector and having conductivity can be used. For example, the primer layer can be formed by applying a binder mixed with a carbon-based conductive additive on the positive electrode current collector to a thickness of 0.1 μm to 50 μm.
　プライマー層用の導電助剤としては、炭素粉末が好ましい。金属系の導電助剤であると、容量密度を上げることは可能であるが、入出力特性が悪くなる場合がある。導電助剤が炭素系であれば、入出力特性が向上しやすくなる。炭素系導電助剤としては、例えば、ＫＢ、ＡＢ、ＶＧＣＦ、グラファイト、グラフェン、カーボンチューブ等が挙げられる。導電助剤は、１種類単独で使用してもよいし、２種類以上を組み合わせて使用してもよい。プライマー層用の導電助剤としては、導電性とコストの観点から、ＫＢまたはＡＢが好ましい。 As the conductive aid for the primer layer, carbon powder is preferable. In the case of a metal-based conductive aid, the capacity density can be increased, but input / output characteristics may be deteriorated. If the conductive assistant is carbon-based, the input / output characteristics are easily improved. Examples of the carbon-based conductive assistant include KB, AB, VGCF, graphite, graphene, and carbon tube. A conductive support agent may be used individually by 1 type, and may be used in combination of 2 or more types. As the conductive aid for the primer layer, KB or AB is preferable from the viewpoint of conductivity and cost.
　プライマー層用のバインダーとしては、炭素系導電助剤を結着できるものであれば、その種類は問わない。ただし、本発明のバインダー、ＰＶＡ、ＣＭＣ、アルギン酸ナトリウム等の水系バインダーを用いてプライマー層を形成すると、活物質層を形成する際に、プライマー層が溶け、効果が顕著に発揮されない場合がある。そのため、このような水系バインダーを用いる際は、あらかじめプライマー層を架橋するとよい。架橋材としては、例えば、ジルコニア化合物、ホウ素化合物、チタン化合物などが挙げられ、プライマー層用スラリー形成時にバインダー量に対して０．１～２０質量％程度添加するとよい。このようにして作製されたプライマー層は、箔状の正極集電体において、水系バインダーを用いて容量密度を向上させることができる。さらに、高い電流で充放電を行っても分極が小さいため、高率充放電特性が良好になる。なお、プライマー層は、箔状の正極集電体だけでなく、三次元形状の正極集電体においても同様の効果を奏する。 The binder for the primer layer is not limited as long as it can bind the carbon-based conductive aid. However, when the primer layer is formed using an aqueous binder such as the binder of the present invention, PVA, CMC, sodium alginate, etc., the primer layer is melted when the active material layer is formed, and the effect may not be exhibited remarkably. Therefore, when using such an aqueous binder, the primer layer may be crosslinked in advance. Examples of the cross-linking material include zirconia compounds, boron compounds, titanium compounds, and the like, and it is preferable to add about 0.1 to 20% by mass with respect to the amount of the binder when forming the primer layer slurry. The primer layer thus produced can improve the capacity density by using an aqueous binder in a foil-like positive electrode current collector. Furthermore, even if charging / discharging is performed at a high current, the polarization is small, so that high rate charge / discharge characteristics are improved. The primer layer has the same effect not only in the foil-shaped positive electrode current collector but also in the three-dimensional positive electrode current collector.
　本発明の非水電解質二次電池用の正極は、例えば、下記組成式１で表される金属酸化物を活物質粒子表面に備える正極活物質と、本発明のバインダーとを用いた非水電解質二次電池用正極であってもよい。
　組成式１：ＬｉαＭβＯγ The positive electrode for a non-aqueous electrolyte secondary battery of the present invention is, for example, a non-aqueous electrolyte using a positive electrode active material comprising a metal oxide represented by the following composition formula 1 on the surface of active material particles and the binder of the present invention. It may be a positive electrode for a secondary battery.
Composition formula 1: LiαMβOγ
　組成式１中、Ｍは、Ａｌ、Ｔｉ、Ｃｒ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｒ、Ｎｂ、Ｍｏ、Ａｇ、Ｔａ、Ｗ、Ｉｒからなる群から選択された少なくとも１種の金属元素であり、０≦α≦６、１≦β≦５、０＜γ≦１２である。このうち、耐熱性の観点から、Ｍは、Ｚｒが好ましい。 In composition formula 1, M is at least one metal element selected from the group consisting of Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ag, Ta, W, and Ir. 0 ≦ α ≦ 6, 1 ≦ β ≦ 5, and 0 <γ ≦ 12. Among these, from the viewpoint of heat resistance, M is preferably Zr.
　なお、本明細書において、「金属酸化物を活物質粒子表面に備える正極活物質」とは、金属酸化物が正極の電極表面にオーバーコート層として備えていること、金属酸化物が正極活物質の粒子表面に被覆されていること、及びその両方が実施されていることを含む。 In this specification, “a positive electrode active material having a metal oxide on the surface of an active material particle” means that the metal oxide is provided as an overcoat layer on the electrode surface of the positive electrode, and the metal oxide is a positive electrode active material. That the particle surface is coated, and that both are performed.
　正極活物質において、活物質粒子表面に金属酸化物を備えることにより、本発明のような水系バインダーを用いる際の懸念である、正極活物質のリチウムの溶け出しによる正極活物質容量の低下、及び充電の際の水系バインダーの酸化分解を防止することができ、高率放電特性をさらに向上させることができる。 In the positive electrode active material, by providing a metal oxide on the surface of the active material particles, a decrease in the positive electrode active material capacity due to the dissolution of lithium in the positive electrode active material, which is a concern when using the aqueous binder as in the present invention, and The oxidative decomposition of the aqueous binder during charging can be prevented, and the high rate discharge characteristics can be further improved.
　さらに、活物質粒子表面に金属酸化物を備えることにより、動作電圧が４Ｖを超えるような正極活物質を、従来の電解液で使用することができる。例えば遷移金属がＮｉやＣｏであるリン酸遷移金属リチウム化合物の２価から４価または４価から２価のレドックス電位は非常に高いため、電解液から電子を奪い、酸化分解するおそれがあるが、活物質粒子表面に耐酸化性のリチウム遷移金属酸化物を備えていることにより、正極活物質が直接電解液に触れることを防ぐことができる。 Furthermore, by providing a metal oxide on the surface of the active material particles, a positive electrode active material having an operating voltage exceeding 4 V can be used in a conventional electrolyte. For example, the transition metal lithium phosphate compound in which the transition metal is Ni or Co has a very high divalent to tetravalent or tetravalent to divalent redox potential, and thus may take electrons from the electrolyte and oxidatively decompose. By providing the active material particle surface with an oxidation-resistant lithium transition metal oxide, it is possible to prevent the positive electrode active material from directly contacting the electrolytic solution.
　金属酸化物が正極の電極表面にオーバーコート層として備えられ、かつ、金属酸化物が活物質粒子表面に被覆されていることにより、この効果はより一層高められる。 This effect is further enhanced by providing the metal oxide as an overcoat layer on the electrode surface of the positive electrode and covering the surface of the active material particles with the metal oxide.
　金属酸化物を活物質粒子表面に被覆する方法としては、特に制限されず、金属酸化物を含む所定量のコーティング液に所定量の活物質粉末を添加した後、混合する浸漬法等、従来行われている方法を用いることができる。より簡便な方法としては、金属酸化物微粒子をスプレーで活物質粒子に吹きかける方法が挙げられる。この方法よれば、活物質粒子表面に金属酸化物を好適に被覆させることができる。スプレーによるコーティング法は、簡単に行うことができ、コストの面でも有利である。電極表面への金属酸化物のコーティングにおいても、同様の方法を用いることができる。 A method for coating the surface of the active material particles with the metal oxide is not particularly limited, and a conventional method such as a dipping method in which a predetermined amount of the active material powder is added to a predetermined amount of the coating liquid containing the metal oxide and then mixed. Known methods can be used. A simpler method includes a method in which metal oxide fine particles are sprayed on the active material particles by spraying. According to this method, the surface of the active material particles can be suitably coated with the metal oxide. The spray coating method can be performed easily and is advantageous in terms of cost. A similar method can be used for coating a metal oxide on the electrode surface.
　金属酸化物が正極の電極表面にオーバーコート層として備えられる場合、電極表面の金属酸化物のオーバーコート層の厚みとしては、０．１～１０μｍ程度であることが好ましい。厚みが０．１μｍ未満であると、正極活物質容量の低下と充電の際の水系バインダーの酸化分解を十分に防止することができない場合がある。また、厚みが１０μｍを超えると、電極厚みが増し、電池容量が低下するだけでなく、電池のインピーダンスを向上させるため高率放電特性が悪くなる傾向がある。 When the metal oxide is provided as an overcoat layer on the electrode surface of the positive electrode, the thickness of the metal oxide overcoat layer on the electrode surface is preferably about 0.1 to 10 μm. If the thickness is less than 0.1 μm, there may be a case where the decrease in the positive electrode active material capacity and the oxidative decomposition of the aqueous binder during charging cannot be sufficiently prevented. On the other hand, when the thickness exceeds 10 μm, not only the electrode thickness increases and the battery capacity decreases, but also the high-rate discharge characteristics tend to deteriorate because the battery impedance is improved.
　正極活物質は、金属酸化物と導電助剤との混合物を活物質粒子表面に備えることができる。この場合、例えば、予め金属酸化物と炭素前躯体との混合物を粒子表面に備え、これを加熱処理法により炭化する方法を採用してもよい。なお、加熱処理法とは、非酸化性雰囲気（還元雰囲気、不活性雰囲気、減圧雰囲気など酸化されにくい状態）で、６００～４，０００℃程度で加熱処理を施して炭素前躯体を炭化させ、導電性を発現させる方法である。 The positive electrode active material can include a mixture of a metal oxide and a conductive additive on the surface of the active material particles. In this case, for example, a method in which a mixture of a metal oxide and a carbon precursor is previously provided on the particle surface and carbonized by a heat treatment method may be employed. The heat treatment method is a non-oxidizing atmosphere (reducing atmosphere, inert atmosphere, reduced pressure atmosphere, etc., which is difficult to oxidize), and heat treatment is performed at about 600 to 4,000 ° C. to carbonize the carbon precursor, This is a method of developing conductivity.
　炭素前躯体としては、加熱処理により炭素材料となりえるものであれば、特に制限されず、例えば、グルコース、クエン酸、ピッチ、タール、電極に用いられるバインダー材料等が挙げられる。 The carbon precursor is not particularly limited as long as it can be a carbon material by heat treatment, and examples thereof include glucose, citric acid, pitch, tar, and a binder material used for an electrode.
　金属酸化物と炭素前躯体との合計を１００質量％とした場合、炭素前躯体の割合は０．５～２０質量％程度であることが好ましい。炭素前躯体の割合が０．５質量％未満であると、正極の導電性を十分に向上させることができない場合がある。また、炭素前躯体の割合が２０質量％を超えると、水系スラリーの作製の際、カーボンが水を弾くため、均一分散することが難しく、正極活物質の凝集を招く可能性が高くなる傾向がある。 When the total of the metal oxide and the carbon precursor is 100% by mass, the proportion of the carbon precursor is preferably about 0.5 to 20% by mass. When the proportion of the carbon precursor is less than 0.5% by mass, the conductivity of the positive electrode may not be sufficiently improved. In addition, when the proportion of the carbon precursor exceeds 20% by mass, the carbon repels water during the production of the aqueous slurry, so that it is difficult to uniformly disperse and the possibility of causing the aggregation of the positive electrode active material tends to increase. is there.
　正極活物質が、炭素被覆されたような粉末である場合や、カーボン系の導電助剤を用いる場合は、水系スラリーの作製の際、カーボンが水を弾くため、正極活物質をスラリー中に均一分散することが難しく、正極活物質の凝集を招く可能性が高くなる。その場合は、スラリーに界面活性剤を添加することが好ましい。界面活性剤としては、サポニン、リン脂質、ペプチド、トリトンなどが有効であり、スラリー全体に対して界面活性剤を０．０１～０．１質量％程度を添加すればよい。 When the positive electrode active material is a carbon-coated powder or when a carbon-based conductive aid is used, the carbon repels water during the preparation of the aqueous slurry, so that the positive electrode active material is uniformly in the slurry. It is difficult to disperse and the possibility of causing aggregation of the positive electrode active material increases. In that case, it is preferable to add a surfactant to the slurry. As the surfactant, saponins, phospholipids, peptides, tritons and the like are effective, and about 0.01 to 0.1% by mass of the surfactant may be added to the whole slurry.
＜負極＞
　上記のとおり、本発明の非水電解質二次電池の電極用バインダーは、集電体からの電極用合剤の剥離や活物質の脱離を効果的に抑制することができ、充放電の繰り返しに対しても優れた結着持続性を有する。このため、本発明のバインダーを負極に用いることにより、電池容量が大きく、充放電サイクル特性に優れた非水電解質二次電池が得られる。 <Negative electrode>
As described above, the binder for an electrode of the nonaqueous electrolyte secondary battery of the present invention can effectively suppress the peeling of the electrode mixture from the current collector and the detachment of the active material, and repeated charge and discharge. In addition, it has excellent binding durability. Therefore, by using the binder of the present invention for the negative electrode, a nonaqueous electrolyte secondary battery having a large battery capacity and excellent charge / discharge cycle characteristics can be obtained.
　本発明における負極は、例えば次のようにして製造されるものである。負極活物質、導電助剤、本発明のバインダー、水などの液状媒体を混合してペースト状のスラリーを負極合剤とする。この負極合剤を負極集電体に塗布することによって本発明の非水電解質二次電池用の負極とすることができる。本発明のバインダーは、予め液状媒体に溶かして用いてもよいし、粉末状の本発明のバインダーと負極活物質とを予め混合し、その後に液状媒体を加えて用いてもよい。 The negative electrode in the present invention is manufactured, for example, as follows. A negative electrode active material, a conductive additive, a binder of the present invention, and a liquid medium such as water are mixed to form a paste slurry as a negative electrode mixture. By applying this negative electrode mixture to the negative electrode current collector, a negative electrode for the non-aqueous electrolyte secondary battery of the present invention can be obtained. The binder of the present invention may be used by previously dissolving in a liquid medium, or the powdered binder of the present invention and a negative electrode active material may be mixed in advance, and then the liquid medium may be added and used.
（負極活物質）
　負極活物質としては、特に制限されず、ケイ素（Ｓｉ）やスズ（Ｓｎ）などのようにリチウムイオンを大量に吸蔵放出可能な材料を用いることができる。このような材料であれば、単体、合金、化合物、固溶体及びケイ素含有材料やスズ含有材料を含む複合活物質の何れであっても、本発明の効果を発揮させることが可能である。ケイ素含有材料としては、Ｓｉ、ＳｉＯx（０．０５＜ｘ＜１．９５）、またはこれらのいずれかにＢ、Ｍｇ、Ｎｉ、Ｔｉ、Ｍｏ、Ｃｏ、Ｃａ、Ｃｒ、Ｃｕ、Ｆｅ、Ｍｎ、Ｎｂ、Ｔａ、Ｖ、Ｗ、Ｚｎ、Ｃ、Ｎ、及びＳｎからなる群から選択された少なくとも１種以上の元素でＳｉの一部を置換した合金や化合物、または固溶体などを用いることができる。これらはケイ素又はケイ素化合物ということができる。スズ含有材料としては、Ｎｉ2Ｓｎ4、Ｍｇ2Ｓｎ、ＳｎＯx（０＜ｘ＜２）、ＳｎＯ2、ＳｎＳｉＯ3、ＬｉＳｎＯなどが挙げられる。これらの中でも、Ｓｉ単体や酸化ケイ素などのケイ素又はケイ素化合物が好ましい。負極活物質は、１種類単独で使用してもよいし、２種類以上を組み合わせて使用してもよい。 (Negative electrode active material)
The negative electrode active material is not particularly limited, and a material that can occlude and release a large amount of lithium ions, such as silicon (Si) or tin (Sn), can be used. With such a material, the effect of the present invention can be exhibited with any of a simple substance, an alloy, a compound, a solid solution, and a composite active material including a silicon-containing material and a tin-containing material. Examples of the silicon-containing material include Si, SiO x (0.05 <x <1.95), or any of them, B, Mg, Ni, Ti, Mo, Co, Ca, Cr, Cu, Fe, Mn, An alloy, compound, solid solution, or the like in which a part of Si is substituted with at least one element selected from the group consisting of Nb, Ta, V, W, Zn, C, N, and Sn can be used. These can be referred to as silicon or silicon compounds. Examples of the tin-containing material include Ni 2 Sn 4 , Mg 2 Sn, SnO x (0 <x <2), SnO 2 , SnSiO 3 , and LiSnO. Among these, silicon or silicon compounds such as Si alone or silicon oxide are preferable. A negative electrode active material may be used individually by 1 type, and may be used in combination of 2 or more types.
　ケイ素又はケイ素化合物を第１負極活物質とし、炭素材料を第２負極活物質として、第１負極活物質及び第２負極活物質はそれぞれ単独でも使用できるが、第１及び第２負極活物質を混合して得られる複合体を負極活物質として使用することがより好ましい。この時、第１及び第２負極活物質の混合比率は、質量比で５／９５～９５／５程度が好ましい。 Silicon or a silicon compound is used as the first negative electrode active material, the carbon material is used as the second negative electrode active material, and the first negative electrode active material and the second negative electrode active material can be used alone, respectively. It is more preferable to use a composite obtained by mixing as a negative electrode active material. At this time, the mixing ratio of the first and second negative electrode active materials is preferably about 5/95 to 95/5 in mass ratio.
　炭素材料としては、非水電解質二次電池で一般に使用される炭素材料であれば、いかなるものでも使用できる。その代表的な例としては、結晶質炭素、非晶質炭素またはこれらを共に使用してもよい。結晶質炭素の例としては、無定形、板状、鱗片状（ｆｌａｋｅ）、球状もしくは繊維状の天然黒鉛、または人造黒鉛のような黒鉛が挙げられる。非晶質炭素の例としては、ソフトカーボン（ｓｏｆｔ　ｃａｒｂｏｎ）、ハードカーボン（ｈａｒｄ　ｃａｒｂｏｎ）、メソフェーズピッチ炭化物、焼成されたコークスなどが挙げられる。第２負極活物質の中でも非晶質炭素が好ましく、ソフトカーボンが製造時の処理温度が低いため製造コストが低く、安価に手に入る点でより好ましい。 As the carbon material, any carbon material that is generally used in non-aqueous electrolyte secondary batteries can be used. As typical examples, crystalline carbon, amorphous carbon, or a combination thereof may be used. Examples of crystalline carbon include amorphous, plate-like, flake, spherical or fibrous natural graphite, or graphite such as artificial graphite. Examples of amorphous carbon include soft carbon, hard carbon, mesophase pitch carbide, calcined coke, and the like. Among the second negative electrode active materials, amorphous carbon is preferable, and soft carbon is more preferable in terms of low manufacturing cost because it has a low processing temperature at the time of manufacturing and low cost.
　ケイ素またはケイ素化合物を含む負極活物質は、充放電時にリチウムとの反応によって体積変化を生じるため、負極活物質と負極集電体との電気的接触不良が発生しやすくなる。このため、電池が充放電サイクルを繰り返すことにより、電池容量が急激に減少し、サイクル寿命を短くする原因となる。これに対して、第２負極活物質として充放電時に体積変化が少ない炭素材料、特に非晶質炭素を使用する場合、ケイ素又はケイ素化合物の体積変化により発生する電気的接触不良を抑制し、電気電導経路の確保により有利に作用する。 Since a negative electrode active material containing silicon or a silicon compound undergoes a volume change due to a reaction with lithium during charging and discharging, poor electrical contact between the negative electrode active material and the negative electrode current collector tends to occur. For this reason, when a battery repeats a charging / discharging cycle, a battery capacity | capacitance reduces rapidly and becomes a cause which shortens cycle life. On the other hand, when using a carbon material with a small volume change during charge / discharge, particularly amorphous carbon, as the second negative electrode active material, the electrical contact failure caused by the volume change of silicon or silicon compound is suppressed. It works more advantageously by securing a conductive path.
　負極活物質の製造方法としては、特に制限されない。また、上記の第１負極活物質と第２負極活物質を混合した負極活物質複合体を製造する際は、両者が均一に分散される方法であれば特に限定されない。第１負極活物質と第２負極活物質の混合、製造方法の一例としては、両活物質をボールミルの中に入れて混合する方法が挙げられる。その他、負極活物質複合体の製造方法として、例えば、第１負極活物質の粒子表面に、第２負極活物質前躯体を担持させ、これを加熱処理法により炭化する方法を採用してもよい。 The method for producing the negative electrode active material is not particularly limited. Moreover, when manufacturing the negative electrode active material composite which mixed said 1st negative electrode active material and 2nd negative electrode active material, if it is a method by which both are disperse | distributed uniformly, it will not specifically limit. An example of a method for mixing and manufacturing the first negative electrode active material and the second negative electrode active material is a method of mixing both active materials in a ball mill. In addition, as a method for producing the negative electrode active material composite, for example, a method in which the second negative electrode active material precursor is supported on the particle surface of the first negative electrode active material and carbonized by a heat treatment method may be employed. .
　第２負極活物質前躯体としては、加熱処理により炭素材料となりえる炭素前駆体であれば、特に制限されず、例えば、グルコース、クエン酸、ピッチ、タール、電極に用いられるバインダー材料などが挙げられる。バインダー材料としては、例えば、本発明のアルキル変性カルボキシル基含有共重合体のほか、ポリフッ化ビニリデン（ＰＶｄＦ）、カルボキシメチルセルロース（ＣＭＣ）、アクリル樹脂、ポリアクリル酸ナトリウム、アルギン酸ナトリウム、ポリイミド（ＰＩ）、ポリテトラフルオロエチレン（ＰＴＦＥ）、ポリアミド、ポリアミドイミド、ポリアクリル、スチレンブタジエンゴム（ＳＢＲ）、ポリビニルアルコール（ＰＶＡ）、エチレン酢酸共重合体（ＥＶＡ）等が挙げられる。また、加熱処理法とは、非酸化性雰囲気（還元雰囲気、不活性雰囲気、減圧雰囲気など酸化されにくい状態）で、６００～４，０００℃で加熱処理を施して炭素前駆体を炭化させ、導電性を得る方法である。 The precursor of the second negative electrode active material is not particularly limited as long as it is a carbon precursor that can be converted into a carbon material by heat treatment, and examples thereof include glucose, citric acid, pitch, tar, and binder materials used for electrodes. . As the binder material, for example, in addition to the alkyl-modified carboxyl group-containing copolymer of the present invention, polyvinylidene fluoride (PVdF), carboxymethyl cellulose (CMC), acrylic resin, sodium polyacrylate, sodium alginate, polyimide (PI), Examples include polytetrafluoroethylene (PTFE), polyamide, polyamideimide, polyacryl, styrene butadiene rubber (SBR), polyvinyl alcohol (PVA), and ethylene acetate copolymer (EVA). In addition, the heat treatment method is a non-oxidizing atmosphere (reducing atmosphere, inert atmosphere, reduced pressure atmosphere, etc., which is difficult to oxidize), heat treatment is performed at 600 to 4,000 ° C. to carbonize the carbon precursor, and conductive It is a way to get sex.
（導電助剤）
　導電助剤は、導電性を有していれば、特に制限されないが、繊維状の炭素であるカーボンナノファイバー又はカーボンナノチューブが好ましい。導電助剤としてカーボンナノファイバー又はカーボンナノチューブを使用する場合、その使用量については、特に制限されないが、例えば、導電助剤全体の３０～１００質量％が好ましく、４０～１００質量％がより好ましい。カーボンナノファイバー又はカーボンナノチューブの使用量が３０質量％未満では負極活物質と負極集電体の間に十分な導電経路が確保されず、特に高速充放電において十分な導電経路を形成することができない場合がある。 (Conductive aid)
The conductive aid is not particularly limited as long as it has conductivity, but is preferably carbon nanofiber or carbon nanotube which is fibrous carbon. When carbon nanofibers or carbon nanotubes are used as the conductive additive, the amount used is not particularly limited, but is preferably 30 to 100% by mass, and more preferably 40 to 100% by mass of the total conductive auxiliary. When the amount of carbon nanofibers or carbon nanotubes used is less than 30% by mass, a sufficient conductive path is not ensured between the negative electrode active material and the negative electrode current collector, and a sufficient conductive path cannot be formed particularly in high-speed charge / discharge. There is a case.
　導電助剤の使用量については、特に制限されないが、例えば、負極活物質、導電助剤及びバインダーの合計質量に対して、好ましくは０．１～２０質量％程度、より好ましくは０．５～１０質量％程度、さらに好ましくは２～５質量％程度が挙げられる。導電助剤の割合が０．１質量％未満であると、負極の導電性を十分に向上させ難くなる。また、導電助剤の割合が２０質量％を超えると、負極活物質の割合が相対的に減少するため電池の充放電時に高容量が得られにくいこと、液状媒体として水を使用する場合にはカーボンが水を弾くため均一分散することが難しく活物質の凝集を招くこと、活物質と比較して小さいため表面積が大きくなり使用するバインダーの量が増えることなどの点で好ましくない。 The amount of the conductive aid used is not particularly limited, but for example, it is preferably about 0.1 to 20% by weight, more preferably 0.5 to 0.5% with respect to the total weight of the negative electrode active material, the conductive aid and the binder. About 10% by mass, more preferably about 2-5% by mass. When the proportion of the conductive aid is less than 0.1% by mass, it is difficult to sufficiently improve the conductivity of the negative electrode. In addition, when the proportion of the conductive additive exceeds 20% by mass, the proportion of the negative electrode active material is relatively reduced, so that it is difficult to obtain a high capacity during charging / discharging of the battery, and when water is used as the liquid medium. Since carbon repels water, it is difficult to uniformly disperse, causing aggregation of the active material, and since it is small compared to the active material, the surface area increases and the amount of binder used increases.
　また、負極における本発明のバインダーの使用量についても、特に制限されないが、例えば、負極活物質、導電助剤、及びバインダーの合計質量に対して、好ましくは０．５質量％以上３０質量％以下、より好ましくは２質量％以上２０質量％以下、さらに好ましくは３質量％以上１２質量％以下が挙げられる。バインダーが多すぎると負極活物質の割合が相対的に減少するため、電池の充放電時に高容量が得られにくく、逆に少なすぎると結着力が充分でないため、充放電サイクル特性が低下してしまう。 Further, the amount of the binder of the present invention used in the negative electrode is not particularly limited, but is preferably 0.5% by mass or more and 30% by mass or less with respect to the total mass of the negative electrode active material, the conductive additive, and the binder, for example. More preferably, 2 mass% or more and 20 mass% or less, More preferably, 3 mass% or more and 12 mass% or less are mentioned. If the amount of the binder is too large, the ratio of the negative electrode active material is relatively reduced, so that it is difficult to obtain a high capacity during charging / discharging of the battery, and conversely, if the amount is too small, the binding force is not sufficient, and the charge / discharge cycle characteristics are reduced. End up.
　負極活物質が、炭素被覆されたような粉末である場合や、カーボン系の導電助剤を用いる場合は、水系スラリーの作製の際、カーボンが水を弾くため、負極活物質をスラリー中に均一分散することが難しく、負極活物質の凝集を招く可能性が高くなる。その場合は、スラリーに界面活性剤を添加することが好ましい。 When the negative electrode active material is a powder coated with carbon or when a carbon-based conductive additive is used, the carbon repels water during the preparation of the aqueous slurry, so the negative electrode active material is uniformly in the slurry. It is difficult to disperse, and the possibility of causing aggregation of the negative electrode active material increases. In that case, it is preferable to add a surfactant to the slurry.
　界面活性剤としては、サポニン、リン脂質、ペプチド、オクチルグルコシド、ドデシル硫酸ナトリウム、ポリオキシレン、ソルビタンモノラウラート、ポリオキシレンソルビタンモノオレアート、エチルエーテル、ポリソルベート、デオキシコレート、トリトンなどが挙げられる。界面活性剤は、合剤全量に対して０．０１～０．１質量％程度添加すればよい。 Examples of the surfactant include saponin, phospholipid, peptide, octyl glucoside, sodium dodecyl sulfate, polyoxylene, sorbitan monolaurate, polyoxylen sorbitan monooleate, ethyl ether, polysorbate, deoxycholate, and triton. The surfactant may be added in an amount of about 0.01 to 0.1% by mass relative to the total amount of the mixture.
（液状媒体）
　液状媒体としては、上記の正極で例示したものと同じものが例示できる。負極合剤に使用する液状媒体の量としては、特に制限されないが、例えば、負極活物質、導電助剤、及びバインダーの合計質量に対して、４０～９００質量％程度が好ましい。液状媒体の量が４０質量％未満であると、作製したスラリーの粘度が高くなるため、負極活物質、導電助剤、及びバインダーがそれぞれ均一分散し難くなる。また、液状媒体の量が９００質量％を超えると、液状媒体の割合が多すぎる。例えば、液状媒体として水を用い、カーボン系の導電助剤を用いる場合にはカーボンが水を弾くため、均一分散することが難しく、活物質の凝集を招く可能性が高くなる。 (Liquid medium)
As a liquid medium, the same thing as what was illustrated by said positive electrode can be illustrated. The amount of the liquid medium used for the negative electrode mixture is not particularly limited, but for example, about 40 to 900% by mass is preferable with respect to the total mass of the negative electrode active material, the conductive auxiliary agent, and the binder. When the amount of the liquid medium is less than 40% by mass, the viscosity of the prepared slurry is increased, so that the negative electrode active material, the conductive auxiliary agent, and the binder are difficult to uniformly disperse. Further, when the amount of the liquid medium exceeds 900% by mass, the ratio of the liquid medium is too large. For example, when water is used as the liquid medium and a carbon-based conductive assistant is used, the carbon repels water, so that it is difficult to uniformly disperse and the possibility of causing aggregation of the active material increases.
（負極集電体）
　負極集電体は、電子伝導性を有し、保持した負極活物質に通電し得る材料であれば、特に限定されない。負極集電体の材料としては、例えば、Ｃ、Ｃｕ、Ｎｉ、Ｆｅ、Ｖ、Ｎｂ、Ｔｉ、Ｃｒ、Ｍｏ、Ｒｕ、Ｒｈ、Ｔａ、Ｗ、Ｏｓ、Ｉｒ、Ｐｔ、Ａｕ、Ａｌ等の導電性物質、これら導電性物質の二種類以上を含有する合金（例えば、ステンレス鋼）などが挙げられる。また、ＦｅにＣｕをめっきしたものであってもよい。電気伝導性が高く、電解液中の安定性と耐酸化性がよい観点から、負極集電体としてはＣ、Ｃｕ、Ｎｉ、ステンレス鋼等が好ましく、さらに材料コストの観点からＣｕ、Ｎｉが好ましい。 (Negative electrode current collector)
The negative electrode current collector is not particularly limited as long as it is a material that has electronic conductivity and can conduct electricity to the held negative electrode active material. Examples of the negative electrode current collector include conductive materials such as C, Cu, Ni, Fe, V, Nb, Ti, Cr, Mo, Ru, Rh, Ta, W, Os, Ir, Pt, Au, and Al. Examples thereof include materials and alloys containing two or more of these conductive materials (for example, stainless steel). Moreover, what plated Cu on Fe may be used. From the viewpoint of high electrical conductivity and good stability and oxidation resistance in the electrolytic solution, the negative electrode current collector is preferably C, Cu, Ni, stainless steel or the like, and more preferably Cu or Ni from the viewpoint of material cost. .
　負極集電体の形状としては、特に制限されないが、例えば、箔状、三次元形状などが挙げられる。なお、三次元形状（発泡メタル、メッシュ、織布、不織布、エキスパンド基材等）とすると、負極集電体との密着性が低いバインダーであっても高い容量密度の電極が得られ、高率充放電特性も良好になる。 The shape of the negative electrode current collector is not particularly limited, and examples thereof include a foil shape and a three-dimensional shape. In addition, when a three-dimensional shape (foam metal, mesh, woven fabric, nonwoven fabric, expanded base material, etc.) is used, a high capacity density electrode can be obtained even with a binder having low adhesion to the negative electrode current collector. Charge / discharge characteristics are also improved.
　＜非水電解質二次電池＞
　上記のとおり、本発明の非水電解質二次電池の電極用バインダーは、集電体からの電極用合剤の剥離や活物質の脱離を効果的に抑制することができ、充放電の繰り返しに対しても優れた結着持続性を有する。このため、本発明のバインダーを電極（正極及び負極の少なくとも一方）に用いた本発明の非水電解質二次電池は、電池容量が大きく、充放電サイクル特性（電池の寿命特性）に優れている。なお、本発明において、非水電解質二次電池には、キャパシタ、コンデンサなども含まれる。 <Nonaqueous electrolyte secondary battery>
As described above, the binder for an electrode of the nonaqueous electrolyte secondary battery of the present invention can effectively suppress the peeling of the electrode mixture from the current collector and the detachment of the active material, and repeated charge and discharge. In addition, it has excellent binding durability. For this reason, the nonaqueous electrolyte secondary battery of the present invention using the binder of the present invention as an electrode (at least one of a positive electrode and a negative electrode) has a large battery capacity and excellent charge / discharge cycle characteristics (battery life characteristics). . In the present invention, the nonaqueous electrolyte secondary battery includes a capacitor and a capacitor.
　本発明の非水電解質二次電池としては、好ましくはリチウムイオン二次電池が挙げられる。リチウムイオン二次電池においては、リチウムイオンを含有する必要があることから、電解質としてはリチウム塩を用いることが好ましい。リチウム塩としては、特に制限されないが、具体例としては、ヘキサフルオロリン酸リチウム、過塩素酸リチウム、テトラフルオロホウ酸リチウム、トリフルオロメタンスルホン酸リチウム、トリフルオロメタンスルホン酸イミドリチウムなどが挙げられる。これらのリチウム塩は、１種類単独で使用してもよいし、２種類以上を組み合わせて使用してもよい。上記のリチウム塩は、電気的陰性度が高くイオン化しやすいことから、充放電サイクル特性に優れ、二次電池の充放電容量を向上させることができる。 The non-aqueous electrolyte secondary battery of the present invention is preferably a lithium ion secondary battery. In the lithium ion secondary battery, since it is necessary to contain lithium ions, it is preferable to use a lithium salt as the electrolyte. The lithium salt is not particularly limited, and specific examples include lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, and lithium trifluoromethanesulfonate. These lithium salts may be used alone or in combination of two or more. Since the above lithium salt has high electronegativity and is easily ionized, it has excellent charge / discharge cycle characteristics and can improve the charge / discharge capacity of the secondary battery.
　電解質の溶媒としては、例えば、プロピレンカーボネート、エチレンカーボネート、ジメチルカーボネート、ジエチルカーボネート、γ－ブチロラクトン等を用いることができる。これらの溶媒は、１種類単独で使用してもよいし、２種類以上を組み合わせて使用してもよい。溶媒としては、特に、プロピレンカーボネート単体、エチレンカーボネートとジエチルカーボネートとの混合物又はγ－ブチロラクトン単体が好適である。なお、上記エチレンカーボネートとジエチルカーボネートとの混合物の混合比は、一方の成分が１０体積％以上９０体積％以下となる範囲で任意に調整することができる。また、本実施形態の非水電解質二次電池の電解質は、固体電解質やイオン性液体であっても構わない。 Examples of the electrolyte solvent include propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and γ-butyrolactone. These solvents may be used alone or in combination of two or more. As the solvent, propylene carbonate alone, a mixture of ethylene carbonate and diethyl carbonate or γ-butyrolactone alone is particularly suitable. In addition, the mixing ratio of the mixture of ethylene carbonate and diethyl carbonate can be arbitrarily adjusted in a range where one component is 10% by volume or more and 90% by volume or less. Further, the electrolyte of the nonaqueous electrolyte secondary battery of the present embodiment may be a solid electrolyte or an ionic liquid.
　非水電解質二次電池の構造としては、特に限定されないが、例えば、積層式電池、捲回式電池などの既存の電池形態・構造が挙げられる。 The structure of the nonaqueous electrolyte secondary battery is not particularly limited, and examples thereof include existing battery forms and structures such as a stacked battery and a wound battery.
　本発明のバインダーを正極及び負極の少なくとも一方に用いた非水電解質二次電池は、充放電サイクル特性に優れる非水電解質二次電池として機能することができる。 The nonaqueous electrolyte secondary battery using the binder of the present invention for at least one of the positive electrode and the negative electrode can function as a nonaqueous electrolyte secondary battery excellent in charge / discharge cycle characteristics.
＜電気機器＞
　本発明の非水電解質二次電池用電極を備えた非水電解質二次電池は、高容量かつ充放電サイクル特性に優れており、様々な電気機器（電気を使用する乗り物などを含む）の電源として、好適に利用することができる。 <Electrical equipment>
The non-aqueous electrolyte secondary battery provided with the electrode for non-aqueous electrolyte secondary battery of the present invention has a high capacity and excellent charge / discharge cycle characteristics, and is a power source for various electric devices (including vehicles using electricity). Can be suitably used.
　電気機器の具体例としては、エアコン、洗濯機、テレビ、冷蔵庫、冷凍庫、冷房機器、ノートパソコン、タブレット、スマートフォン、パソコンキーボード、パソコン用ディスプレイ、デスクトップ型パソコン、ＣＲＴモニター、プリンター、一体型パソコン、マウス、ハードディスク、パソコン周辺機器、アイロン、衣類乾燥機、ウインドウファン、トランシーバー、送風機、換気扇、テレビ、音楽レコーダー、音楽プレーヤー、オーブン、レンジ、洗浄機能付便座、温風ヒーター、カーコンポ、カーナビ、懐中電灯、加湿器、携帯カラオケ機、換気扇、乾燥機、空気清浄器、携帯電話、非常用電灯、ゲーム機、血圧計、コーヒーミル、コーヒーメーカー、こたつ、コピー機、ディスクチェンジャー、ラジオ、ジューサー、シュレッダー、浄水器、照明器具、除湿器、食器乾燥機、炊飯器、ステレオ、ストーブ、スピーカー、ズボンプレッサー、掃除機、体脂肪計、体重計、ヘルスメーター、ムービープレーヤー、電気カーペット、電気釜、電気かみそり、電気スタンド、電気ポット、電子ゲーム機、携帯ゲーム機、電子辞書、電子手帳、電子レンジ、電磁調理器、電卓、電動カート、電動車椅子、電動工具、電動歯ブラシ、あんか、散髪器具、電話機、時計、インターホン、エアサーキュレーター、電撃殺虫器、ホットプレート、トースター、ドライヤー、電動ドリル、給湯器、パネルヒーター、粉砕機、はんだごて、ビデオカメラ、ビデオデッキ、ファクシミリ、フードプロセッサー、布団乾燥機、ヘッドホン、マイク、マッサージ機、ミキサー、ミシン、もちつき機、床暖房パネル、ランタン、リモコン、冷温庫、冷水器、冷風器、ワープロ、泡だて器、電子楽器、オートバイ、おもちゃ類、芝刈り機、うき、自転車、自動車、ハイブリッド自動車、プラグインハイブリッド自動車、電気自動車、鉄道、船、飛行機、非常用蓄電池などが挙げられる。 Specific examples of electrical equipment include air conditioners, washing machines, televisions, refrigerators, freezers, air conditioners, notebook computers, tablets, smartphones, computer keyboards, computer displays, desktop computers, CRT monitors, printers, integrated computers, mice , Hard disk, computer peripherals, iron, clothes dryer, window fan, walkie-talkie, blower, ventilation fan, TV, music recorder, music player, oven, range, toilet seat with washing function, hot air heater, car component, car navigation, flashlight, Humidifier, portable karaoke machine, ventilation fan, dryer, air cleaner, mobile phone, emergency light, game machine, blood pressure monitor, coffee mill, coffee maker, kotatsu, copy machine, disk changer, radio, juicer, shredder Water purifier, lighting equipment, dehumidifier, dish dryer, rice cooker, stereo, stove, speaker, trouser press, vacuum cleaner, body fat scale, weight scale, health meter, movie player, electric carpet, electric kettle, electric razor, Desk lamp, electric kettle, electronic game machine, portable game machine, electronic dictionary, electronic notebook, microwave oven, electromagnetic cooker, calculator, electric cart, electric wheelchair, electric tool, electric toothbrush, red pepper, haircut appliance, telephone, clock , Intercom, air circulator, electric shock insecticide, hot plate, toaster, dryer, electric drill, water heater, panel heater, crusher, soldering iron, video camera, video deck, facsimile, food processor, futon dryer, headphones, Microphone, massage machine, mixer, sewing machine, mochi machine, floor Tubular panel, lantern, remote control, cold / hot storage, water cooler, cold air blower, word processor, bubble blower, electronic musical instrument, motorcycle, toys, lawn mower, Uki, bicycle, car, hybrid car, plug-in hybrid car, electric Examples include automobiles, railways, ships, airplanes, and emergency storage batteries.
　以下に、実施例及び比較例を挙げて本発明を説明するが、本発明はこれに限定されない。なお、本実施例における部及び％は、特記しない限り質量基準である。実施例及び比較例中の評価は、それぞれ以下の条件にて行った。 Hereinafter, the present invention will be described with reference to examples and comparative examples, but the present invention is not limited thereto. In addition, unless otherwise indicated, the part and% in a present Example are mass references | standards. Evaluation in Examples and Comparative Examples was performed under the following conditions, respectively.
（１）折り曲げ試験
　電極を幅３ｃｍ×長さ９ｃｍに切り、長さ方向の中央（４．５ｃｍの所）に直径１ｍｍのステンレス丸棒を当てて１８０°折り曲げたときの折り曲げ部分の塗膜の状態を目視により観察し、欠けが無い場合を○、欠けがある場合を×と判定する。 (1) Bending test The electrode was cut into 3 cm width x 9 cm length, and a 1 mm diameter stainless steel round bar was applied to the center in the length direction (4.5 cm), and the coating film of the bent portion was bent 180 °. The state is visually observed, and a case where there is no chipping is determined as ◯, and a case where there is a chipping is determined as x.
（２）電池特性の測定
　（電池の製造）
　下記の実施例及び比較例で得られた正極及び負極を直径１５ｍｍの円形シートに切り抜いた。次に、正極及び負極の間に、直径１８ｍｍ、厚さ２５μｍの円形ポリプロピレン製多孔膜からなるセパレーターを介在させた状態で、互いに活物質面を対向させて、外装容器底面に正極のアルミニウム箔が接触するように配置した。次に、負極の銅箔上にエキスパンドメタルを入れ、ポリプロピレン製パッキンを設置したステンレス鋼製のコイン型外装容器（直径２０ｍｍ、高さ１．８ｍｍ、ステンレス鋼厚さ０．２５ｍｍ）中に収納した。この容器中に電解液を空気が残らないように注入した。次に、ポリプロピレン製パッキンを介して外装容器に厚さ０．２ｍｍのステンレス鋼のキャップをかぶせて固定し、電池缶を封止して、直径２０ｍｍ、厚さ約２ｍｍのコイン型電池を製造した。なお、電解液はエチレンカーボネートとジエチルカーボネートの１：２（体積比）混合液中にＬｉＰＦ6を１モル／リットルの割合で溶解したものを用いた。 (2) Measurement of battery characteristics (Manufacture of batteries)
The positive electrode and negative electrode obtained in the following Examples and Comparative Examples were cut out into a circular sheet having a diameter of 15 mm. Next, with the separator made of a circular polypropylene porous film having a diameter of 18 mm and a thickness of 25 μm interposed between the positive electrode and the negative electrode, the active material surfaces are opposed to each other, and the positive electrode aluminum foil is placed on the bottom surface of the outer container. Arranged to contact. Next, an expanded metal was put on the copper foil of the negative electrode and stored in a stainless steel coin-type outer container (diameter 20 mm, height 1.8 mm, stainless steel thickness 0.25 mm) with polypropylene packing installed. . The electrolyte was poured into the container so that no air remained. Next, a 0.2 mm-thick stainless steel cap was placed on the outer container through polypropylene packing, and the battery can was sealed to produce a coin-type battery having a diameter of 20 mm and a thickness of about 2 mm. . Incidentally, the electrolytic solution 1 of ethylene carbonate and diethyl carbonate: a LiPF 6 was obtained by dissolving at a rate of 1 mol / l in 2 (by volume) mixture.
（放電容量の測定）
　上記で得られた電池について、２５℃下で、３Ｖから４．２Ｖまで０．１Ｃの定電流で充電を行ったのち直ちに、０．１Ｃのレートで放電を行った。次に、同様にして、直ちに１Ｃ、２Ｃ、５Ｃ、及び７Ｃのレートでの充放電を順に行い、それぞれの放電容量を測定した。なお、放電容量は、０．１Ｃ放電時を１００としたときの所定レートでの相対値とした。結果を表３に示す。 (Measurement of discharge capacity)
The battery obtained above was charged at a constant current of 0.1 C from 3 V to 4.2 V at 25 ° C., and then immediately discharged at a rate of 0.1 C. Next, in the same manner, charging and discharging were sequentially performed at rates of 1C, 2C, 5C, and 7C in order, and each discharge capacity was measured. Note that the discharge capacity was a relative value at a predetermined rate when 100 at 0.1 C discharge. The results are shown in Table 3.
（５０回充放電を繰り返した後の放電容量の測定）
　上記で得られた電池について、２５℃下で、３Ｖから４．２Ｖまで０．１Ｃの定電流で充電及び放電を各１回行ったのち直ちに、１Ｃのレートにて充電及び放電を５０回繰り返した。なお、放電容量は、０．１Ｃ放電時の容量を１００としたときの１Ｃで５０回目の放電容量（相対値）とした。結果を表３に示す。 (Measurement of discharge capacity after 50 charge / discharge cycles)
The battery obtained above was charged and discharged once at a constant current of 0.1 C from 3 V to 4.2 V at 25 ° C., and then immediately charged and discharged 50 times at a rate of 1 C. It was. The discharge capacity was the 50th discharge capacity (relative value) at 1 C when the capacity at 0.1 C discharge was 100. The results are shown in Table 3.
（実施例１）
　撹拌機、温度計、窒素吹き込み管及び冷却管を備えた５００ｍＬ容の四つ口フラスコに、アクリル酸４５ｇ（０．６２５モル）、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルとしてのブレンマーＶＭＡ７０（日本油脂株式会社製、メタクリル酸ステアリル１０～２０質量部、メタクリル酸エイコサニル１０～２０質量部、メタクリル酸ベヘニル５９～８０質量部、メタクリル酸テトラコサニルの含有量が１質量部以下の混合物）０．４５ｇ、ノルマルヘキサン１５０ｇ、及び２，２’－アゾビスメチルイソブチレート０．０８１ｇ（０．０００３５モル）を仕込んだ。次いで、均一に撹拌、混合した後、反応容器の上部空間、原料及び溶媒中に存在している酸素を除去するために、溶液中に窒素ガスを吹き込んだ。次いで、窒素雰囲気下、６０～６５℃に保持して４時間反応させた。反応終了後、生成したスラリーを９０℃に加熱して、ノルマルヘキサンを留去し、さらに、１１０℃、１０ｍｍＨｇにて８時間減圧乾燥することにより、白色微粉末状のアルキル変性カルボキシル基含有共重合体（ａ）を４３ｇ得た。 Example 1
In a 500 mL four-necked flask equipped with a stirrer, thermometer, nitrogen blowing tube and cooling tube, 45 g (0.625 mol) of acrylic acid and (meth) acrylic acid having an alkyl group with 18 to 24 carbon atoms BLEMMER VMA70 as an alkyl ester (manufactured by NOF Corporation, stearyl methacrylate 10-20 parts by mass, eicosanyl methacrylate 10-20 parts by mass, behenyl methacrylate 59-80 parts by mass, tetracosanyl methacrylate content 1 part by mass 0.45 g of the following mixture), 150 g of normal hexane, and 0.081 g (0.00035 mol) of 2,2′-azobismethylisobutyrate were charged. Next, after stirring and mixing uniformly, nitrogen gas was blown into the solution in order to remove oxygen present in the upper space of the reaction vessel, the raw material, and the solvent. Subsequently, the reaction was carried out for 4 hours while maintaining the temperature at 60 to 65 ° C. in a nitrogen atmosphere. After completion of the reaction, the resulting slurry was heated to 90 ° C. to distill off normal hexane, and further dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain a white fine powdery alkyl-modified carboxyl group-containing copolymer. 43g of union (a) was obtained.
（実施例２）
　実施例１において、ブレンマーＶＭＡ７０（日本油脂株式会社製）０．４５ｇに代えて、アクリル酸ベヘニル（日本油脂株式会社製ブレンマーＶＡ）１．３５ｇを使用したこと以外は、実施例１と同様にして、白色微粉末状のアルキル変性カルボキシル基含有共重合体（ｂ）４４ｇを得た。 (Example 2)
In Example 1, it replaced with Blemmer VMA70 (Nippon Yushi Co., Ltd.) 0.45g, and it was carried out similarly to Example 1 except having used 1.35 g of behenyl acrylate (Nippon Yushi Co., Ltd. Blemmer VA). 44 g of an alkyl-modified carboxyl group-containing copolymer (b) in the form of white fine powder was obtained.
（実施例３）
　実施例１において、ブレンマーＶＭＡ７０（日本油脂株式会社製）０．４５ｇに代えて、メタクリル酸ステアリル（日本油脂株式会社製ブレンマーＳＭＡ）２．２５ｇを使用したこと以外は、実施例１と同様にして、白色微粉末状のアルキル変性カルボキシル基含有共重合体（ｃ）４５ｇを得た。 Example 3
In Example 1, it replaced with 0.45g of Blemmer VMA70 (Nippon Yushi Co., Ltd.) 0.45g, It was carried out similarly to Example 1 except having used 2.25 g of stearyl methacrylate (Nippon Yushi Co., Ltd. Blemmer SMA). As a result, 45 g of an alkyl-modified carboxyl group-containing copolymer (c) in the form of white fine powder was obtained.
（実施例４）
　実施例１において、アクリル酸４５ｇ（０．６２５モル）、ブレンマーＶＭＡ７０（日本油脂株式会社製）０．４５ｇ、ノルマルヘキサン１５０ｇ、２，２’－アゾビスメチルイソブチレート０．０８１ｇ（０．０００３５モル）に加えて、ペンタエリトリトールアリルエーテル０．０２ｇを用いたこと以外は、実施例１と同様にして、白色微粉末状のアルキル変性カルボキシル基含有共重合体（ｄ）を４３ｇ得た。 Example 4
In Example 1, acrylic acid 45 g (0.625 mol), Blemmer VMA70 (manufactured by NOF Corporation) 0.45 g, normal hexane 150 g, 2,2′-azobismethylisobutyrate 0.081 g (0.00035) In addition to using 0.02 g of pentaerythritol allyl ether, 43 g of an alkyl-modified carboxyl group-containing copolymer (d) in the form of a white fine powder was obtained in the same manner as in Example 1.
（実施例５）
　実施例４において、ブレンマーＶＭＡ７０（日本油脂株式会社製）０．４５ｇに代えて、アクリル酸ベヘニル（日本油脂株式会社製ブレンマーＶＡ）１．３５ｇを使用したこと以外は、実施例４と同様にして、白色微粉末状のアルキル変性カルボキシル基含有共重合体（ｅ）４４ｇを得た。 (Example 5)
In Example 4, it replaced with Blemmer VMA70 (Nippon Yushi Co., Ltd.) 0.45g, and it was carried out similarly to Example 4 except having used 1.35g of acrylic acid behenyl (Nippon Yushi Co., Ltd. Blemmer VA). 44 g of an alkyl-modified carboxyl group-containing copolymer (e) in the form of a white fine powder was obtained.
（実施例６）
　実施例４において、ブレンマーＶＭＡ７０（日本油脂株式会社製）０．４５ｇに代えて、メタクリル酸ステアリル（日本油脂株式会社製ブレンマーＳＭＡ）２．２５ｇを使用したこと以外は、実施例４と同様にして、白色微粉末状のアルキル変性カルボキシル基含有共重合体（ｆ）４５ｇを得た。 (Example 6)
In Example 4, it replaced with Blemmer VMA70 (Nippon Yushi Co., Ltd.) 0.45g, and used the same method as Example 4 except having used 2.25g of stearyl methacrylate (Nippon Yushi Co., Ltd. Blemmer SMA). Thus, 45 g of an alkyl-modified carboxyl group-containing copolymer (f) in the form of a white fine powder was obtained.
（比較例１）
　撹拌機、温度計、窒素吹き込み管及び冷却管を備えた５００ｍL容の四つ口フラスコに、アクリル酸４５ｇ（０．６２５モル）、ペンタエリトリトールアリルエーテル０．０９ｇ、ノルマルヘキサン１５０ｇ、及び２，２’－アゾビスメチルイソブチレート０．０８１ｇ（０．０００３５モル）を仕込んだ。次いで均一に撹拌、混合した後、反応容器の上部空間、原料及び溶媒中に存在している酸素を除去するために、溶液中に窒素ガスを吹き込んだ。次いで、窒素雰囲気下、６０～６５℃に保持して４時間反応させた。反応終了後、生成したスラリーを９０℃に加熱して、ノルマルヘキサンを留去し、さらに、１１０℃、１０ｍｍＨｇにて８時間減圧乾燥することにより、白色微粉末状の重合体（ｇ）４２ｇを得た。 (Comparative Example 1)
In a 500 mL four-necked flask equipped with a stirrer, thermometer, nitrogen blowing tube and cooling tube, 45 g (0.625 mol) of acrylic acid, 0.09 g of pentaerythritol allyl ether, 150 g of normal hexane, and 2,2 0.081 g (0.00035 mol) of '-azobismethylisobutyrate was charged. Next, after stirring and mixing uniformly, nitrogen gas was blown into the solution in order to remove oxygen present in the upper space of the reaction vessel, the raw materials and the solvent. Subsequently, the reaction was carried out for 4 hours while maintaining the temperature at 60 to 65 ° C. in a nitrogen atmosphere. After completion of the reaction, the resulting slurry was heated to 90 ° C. to distill off normal hexane, and further dried under reduced pressure at 110 ° C. and 10 mmHg for 8 hours to obtain 42 g of white fine powdery polymer (g). Obtained.
（比較例２）
　実施例１において、ブレンマーＶＭＡ（日本油脂株式会社製）０．４５ｇに代えてメタクリル酸ラウリル（日本油脂株式会社製ブレンマーＬＭＡ）０．４５ｇを使用したこと以外は、実施例１と同様にして、白色微粉末状のアルキル変性カルボキシル基含有共重合体（ｈ）４６ｇを得た。 (Comparative Example 2)
In Example 1, except that 0.45 g of lauryl methacrylate (Blemmer LMA manufactured by NOF Corporation) was used instead of 0.45 g of BLEMMER VMA (manufactured by NOF Corporation), the same as in Example 1, 46 g of an alkyl-modified carboxyl group-containing copolymer (h) in the form of white fine powder was obtained.
　実施例１～６及び比較例１～２において使用した主要原料とその使用量を表１～２に示す。なお、括弧内は、使用した（メタ）アクリル酸の質量を１００とした場合の各原料の質量％を示す。 Tables 1 and 2 show the main raw materials used in Examples 1 to 6 and Comparative Examples 1 and 2 and the amounts used. The values in parentheses indicate the mass% of each raw material when the mass of (meth) acrylic acid used is 100.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
＜電極及び電池の製造＞
（実施例７）
　実施例１で得られたアルキル変性カルボキシル基含有共重合体（ａ）１ｇを水に溶解し、６質量％水酸化ナトリウム水溶液を用いｐＨを６～８に調整して１０質量％のバインダー水溶液を作製した。
　得られたバインダー水溶液５０質量部、正極活物質としてリン酸鉄リチウム９１質量部、導電助剤としてカーボンナノチューブ４質量部に対して水を加えて撹拌し、固形分濃度が５０質量％のスラリーを調製した。得られたスラリーをアルミ箔に塗布し、１４０℃で１２時間乾燥後、ロールプレス機にかけて正極を得た。得られた正極を用い、上記の方法で折り曲げ試験を実施した。結果を表３に示す。
　負極活物質として天然黒鉛９５質量部、導電助剤としてカーボンナノチューブ２質量部、及びＰＶｄＦ３質量部に対してＮ－メチルピロリドンを加えて撹拌し、固形分濃度が５０質量％のスラリーを調製した。得られたスラリーを銅箔に塗布し、１４０℃１２時間乾燥し負極を得た。
　得られた正極、及び負極を用いて非水電解質二次電池を作製し、上記の電池特性を評価した。結果を表３に示す。 <Manufacture of electrodes and batteries>
(Example 7)
1 g of the alkyl-modified carboxyl group-containing copolymer (a) obtained in Example 1 was dissolved in water, and the pH was adjusted to 6 to 8 using a 6% by mass sodium hydroxide aqueous solution to obtain a 10% by mass binder aqueous solution. Produced.
Water was added to 50 parts by mass of the obtained binder aqueous solution, 91 parts by mass of lithium iron phosphate as the positive electrode active material, and 4 parts by mass of carbon nanotubes as the conductive auxiliary agent, and stirred to obtain a slurry having a solid content concentration of 50% by mass. Prepared. The obtained slurry was applied to an aluminum foil, dried at 140 ° C. for 12 hours, and then subjected to a roll press to obtain a positive electrode. Using the obtained positive electrode, a bending test was performed by the above method. The results are shown in Table 3.
N-methylpyrrolidone was added to 95 parts by mass of natural graphite as a negative electrode active material, 2 parts by mass of carbon nanotubes as a conductive auxiliary agent, and 3 parts by mass of PVdF and stirred to prepare a slurry having a solid content concentration of 50% by mass. The obtained slurry was applied to a copper foil and dried at 140 ° C. for 12 hours to obtain a negative electrode.
Using the obtained positive electrode and negative electrode, a non-aqueous electrolyte secondary battery was produced, and the battery characteristics were evaluated. The results are shown in Table 3.
（実施例８）
　実施例７において、アルキル変性カルボキシル基含有共重合体（ａ）１ｇに代えて、アルキル変性カルボキシル基含有共重合体（ｂ）１ｇとしたこと以外は、実施例７と同様にして、正極を得た。得られた正極を用い、実施例７と同様にして非水電解質二次電池を作製し、電池特性評価をした。結果を表３に示す。 (Example 8)
A positive electrode was obtained in the same manner as in Example 7, except that 1 g of the alkyl-modified carboxyl group-containing copolymer (b) was used instead of 1 g of the alkyl-modified carboxyl group-containing copolymer (a) in Example 7. It was. Using the obtained positive electrode, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 7, and the battery characteristics were evaluated. The results are shown in Table 3.
（実施例９）
　実施例７において、アルキル変性カルボキシル基含有共重合体（ａ）１ｇに代えて、アルキル変性カルボキシル基含有共重合体（ｃ）１ｇを水に溶解し、６質量％水酸化ナトリウム水溶液を用いｐＨを６～８に調整して１０質量％のバインダー水溶液を作製した後、得られたバインダー水溶液８０質量部、正極活物質としてリン酸鉄リチウム８８質量部、導電助剤としてカーボンナノチューブ４質量部に対して水を加えて撹拌したこと以外は、実施例７と同様にして、正極を得た。得られた正極を用い、実施例７と同様にして非水電解質二次電池を作製し、電池特性評価をした。結果を表３に示す。 Example 9
In Example 7, instead of 1 g of the alkyl-modified carboxyl group-containing copolymer (a), 1 g of the alkyl-modified carboxyl group-containing copolymer (c) was dissolved in water, and the pH was adjusted using a 6% by mass aqueous sodium hydroxide solution. After preparing a 10% by weight binder aqueous solution by adjusting to 6-8, 80 parts by weight of the obtained binder aqueous solution, 88 parts by weight of lithium iron phosphate as the positive electrode active material, and 4 parts by weight of carbon nanotubes as the conductive assistant A positive electrode was obtained in the same manner as in Example 7 except that water was added and stirred. Using the obtained positive electrode, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 7, and the battery characteristics were evaluated. The results are shown in Table 3.
（実施例１０）
　実施例７において、アルキル変性カルボキシル基含有共重合体（ａ）１ｇに代えて、アルキル変性カルボキシル基含有共重合体（ｄ）０．５ｇを水に溶解し、６質量％水酸化ナトリウム水溶液を用いｐＨを６～８に調整して４質量％のバインダー水溶液を作製した後、得られたバインダー水溶液５０質量部、正極活物質としてリン酸鉄リチウム９４質量部、導電助剤としてカーボンナノチューブ４質量部に対して水を加えて撹拌したこと以外は、実施例７と同様にして、正極を得た。得られた正極を用い、実施例７と同様にして非水電解質二次電池を作製し、電池特性評価をした。結果を表３に示す。 (Example 10)
In Example 7, instead of 1 g of the alkyl-modified carboxyl group-containing copolymer (a), 0.5 g of the alkyl-modified carboxyl group-containing copolymer (d) was dissolved in water, and a 6% by mass sodium hydroxide aqueous solution was used. After adjusting the pH to 6 to 8 to prepare a 4% by mass binder aqueous solution, the obtained binder aqueous solution 50 parts by mass, 94 parts by mass of lithium iron phosphate as a positive electrode active material, 4 parts by mass of carbon nanotubes as a conductive assistant A positive electrode was obtained in the same manner as in Example 7 except that water was added and stirred. Using the obtained positive electrode, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 7, and the battery characteristics were evaluated. The results are shown in Table 3.
（実施例１１）
　実施例１０において、アルキル変性カルボキシル基含有共重合体（ｄ）０．５ｇに代えて、アルキル変性カルボキシル基含有共重合体（ｅ）０．５ｇを水に溶解し、６質量％水酸化ナトリウム水溶液を用いｐＨを６～８に調整して１０質量％のバインダー水溶液を作製したこと以外は、実施例１０と同様にして、正極を得た。得られた正極を用い、実施例７と同様にして非水電解質二次電池を作製し、電池特性評価をした。結果を表３に示す。 (Example 11)
In Example 10, instead of 0.5 g of the alkyl-modified carboxyl group-containing copolymer (d), 0.5 g of the alkyl-modified carboxyl group-containing copolymer (e) was dissolved in water, and a 6% by mass aqueous sodium hydroxide solution A positive electrode was obtained in the same manner as in Example 10 except that the pH was adjusted to 6 to 8 to prepare a 10% by mass aqueous binder solution. Using the obtained positive electrode, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 7, and the battery characteristics were evaluated. The results are shown in Table 3.
（実施例１２）
　実施例１０において、アルキル変性カルボキシル基含有共重合体（ｄ）０．５ｇに代えて、アルキル変性カルボキシル基含有共重合体（ｆ）０．５ｇを水に溶解し、６質量％水酸化ナトリウム水溶液を用いｐＨを６～８に調整して１０質量％のバインダー水溶液を作製したこと以外は、実施例１０と同様にして、正極を得た。得られた正極を用い、実施例７と同様にして非水電解質二次電池を作製し、電池特性評価をした。結果を表３に示す。 Example 12
In Example 10, instead of 0.5 g of the alkyl-modified carboxyl group-containing copolymer (d), 0.5 g of the alkyl-modified carboxyl group-containing copolymer (f) was dissolved in water, and a 6% by mass aqueous sodium hydroxide solution A positive electrode was obtained in the same manner as in Example 10 except that the pH was adjusted to 6 to 8 to prepare a 10% by mass aqueous binder solution. Using the obtained positive electrode, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 7, and the battery characteristics were evaluated. The results are shown in Table 3.
（実施例１３）
　実施例７の負極の作製において、天然黒鉛９５質量部、導電助剤としてカーボンナノチューブ２質量部及びアルキル変性カルボキシル基含有共重合体（ａ）３質量部に対して水を加え撹拌し、６質量％水酸化ナトリウム水溶液を用いｐＨを６～８に調整して、固形分が５０質量％のスラリーを調製して負極を得たこと以外は、実施例７と同様にして、負極を得た。得られた負極を用い、実施例７と同様にして非水電解質二次電池を作製し、電池特性評価をした。結果を表３に示す。 (Example 13)
In preparation of the negative electrode of Example 7, water was added to 95 parts by mass of natural graphite, 2 parts by mass of carbon nanotubes and 3 parts by mass of the alkyl-modified carboxyl group-containing copolymer (a) as a conductive additive, and 6 masses was stirred. A negative electrode was obtained in the same manner as in Example 7 except that a negative electrode was obtained by adjusting the pH to 6 to 8 using a% sodium hydroxide aqueous solution and preparing a slurry having a solid content of 50% by mass. Using the obtained negative electrode, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 7, and the battery characteristics were evaluated. The results are shown in Table 3.
（比較例３）
　実施例７において、アルキル変性カルボキシル基含有共重合体（ａ）１ｇに代えて、比較例１で得た重合体（ｇ）０．５ｇを水に溶解し、６質量％水酸化ナトリウム水溶液を用いｐＨを６～８に調整して３質量％のバインダー水溶液を作製した後、得られたバインダー水溶液１００質量部、正極活物質としてリン酸鉄リチウム９３質量部、導電助剤としてカーボンナノチューブ４質量部に対して水を加えて撹拌したこと以外は、実施例７と同様にして、正極を得た。得られた正極を用い、実施例７と同様にして非水電解質二次電池を作製し、電池特性評価をした。結果を表３に示す。 (Comparative Example 3)
In Example 7, instead of 1 g of the alkyl-modified carboxyl group-containing copolymer (a), 0.5 g of the polymer (g) obtained in Comparative Example 1 was dissolved in water, and a 6 mass% sodium hydroxide aqueous solution was used. After adjusting pH to 6-8 and preparing 3 mass% binder aqueous solution, 100 mass parts of obtained binder aqueous solution, 93 mass parts of lithium iron phosphate as a positive electrode active material, 4 mass parts of carbon nanotubes as a conductive support agent A positive electrode was obtained in the same manner as in Example 7 except that water was added and stirred. Using the obtained positive electrode, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 7, and the battery characteristics were evaluated. The results are shown in Table 3.
（比較例４）
　実施例７において、アルキル変性カルボキシル基含有共重合体（ａ）１ｇに代えて、比較例２で得たアルキル変性カルボキシル基含有共重合体（ｈ）１ｇとしたこと以外は、実施例７と同様にして、正極を得た。得られた正極を用い、実施例７と同様にして非水電解質二次電池を作製し、電池特性評価をした。結果を表３に示す。 (Comparative Example 4)
Example 7 is the same as Example 7 except that 1 g of the alkyl-modified carboxyl group-containing copolymer (h) obtained in Comparative Example 2 is used instead of 1 g of the alkyl-modified carboxyl group-containing copolymer (a). Thus, a positive electrode was obtained. Using the obtained positive electrode, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 7, and the battery characteristics were evaluated. The results are shown in Table 3.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表３に示される折り曲げ試験の結果から、実施例１～６で得られたバインダー（ａ）～（ｆ）を正極に用いた実施例７～１３では、正極を折り曲げた場合の欠けが無く、バインダーが強い結着性を有することが分かる。一方、比較例１で得られたバインダー（ｇ）を用いた比較例３では、バインダー（ｇ）に（メタ）アクリル酸アルキルエステルが用いられておらず、また、比較例２で得られたバインダー（ｈ）を用いた比較例４では、アルキル基の炭素数が１２と短いため、結着強度が不足し、正極の折り曲げ試験において割れや部分欠損が発生した。さらに、電池の放電容量の測定結果から、実施例７～１３では、何れも５０回充放電後の放電容量の劣化が抑制されているが、比較例３～４では、５０回充放電後の放電容量の劣化が大きかった。この原因としては、正極におけるバインダーの結着強度不足、正極の不均一性等の理由が考えられる。 From the results of the bending test shown in Table 3, in Examples 7 to 13 where the binders (a) to (f) obtained in Examples 1 to 6 were used for the positive electrode, there was no chipping when the positive electrode was bent, It can be seen that the binder has a strong binding property. On the other hand, in Comparative Example 3 using the binder (g) obtained in Comparative Example 1, no (meth) acrylic acid alkyl ester was used in the binder (g), and the binder obtained in Comparative Example 2 was used. In Comparative Example 4 using (h), since the carbon number of the alkyl group was as short as 12, the binding strength was insufficient, and cracks and partial defects occurred in the positive electrode bending test. Furthermore, from the measurement results of the discharge capacity of the battery, in Examples 7 to 13, the deterioration of the discharge capacity after 50 times of charge / discharge was suppressed, but in Comparative Examples 3 to 4, after the 50th charge / discharge. The deterioration of the discharge capacity was great. This may be due to insufficient binding strength of the binder in the positive electrode, non-uniformity of the positive electrode, or the like.

Claims (9)

  1. 　（メタ）アクリル酸と、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルとを共重合させたアルキル変性カルボキシル基含有共重合体からなる、非水電解質二次電池の電極用バインダー。 Electrode of non-aqueous electrolyte secondary battery comprising an alkyl-modified carboxyl group-containing copolymer obtained by copolymerizing (meth) acrylic acid and (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms Binder.
  2. 　前記（メタ）アクリル酸１００質量部に対して、前記アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルが０．１～１０質量部の割合で共重合されてなる、請求項１に記載の非水電解質二次電池の電極用バインダー。 The (meth) acrylic acid alkyl ester having 18 to 24 carbon atoms in the alkyl group is copolymerized at a ratio of 0.1 to 10 parts by mass with respect to 100 parts by mass of the (meth) acrylic acid. Item 2. A binder for an electrode of a nonaqueous electrolyte secondary battery according to Item 1.
  3. 　エチレン性不飽和基を２個以上有する化合物が、前記（メタ）アクリル酸１００質量部に対して０．５質量部以下の割合で共重合されてなる、請求項１または２に記載の非水電解質二次電池の電極用バインダー。 The non-water according to claim 1 or 2, wherein the compound having two or more ethylenically unsaturated groups is copolymerized at a ratio of 0.5 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic acid. Electrode secondary battery electrode binder.
  4. 　前記エチレン性不飽和基を２個以上有する化合物が、ペンタエリトリトールアリルエーテル、ジエチレングリコールジアリルエーテル、ポリエチレングリコールジアリルエーテル、及びポリアリルサッカロースからなる群から選択された少なくとも１種である、請求項３に記載の非水電解質二次電池の電極用バインダー。 The compound having two or more ethylenically unsaturated groups is at least one selected from the group consisting of pentaerythritol allyl ether, diethylene glycol diallyl ether, polyethylene glycol diallyl ether, and polyallyl saccharose. Non-aqueous electrolyte secondary battery electrode binder.
  5. 　活物質、導電助剤、及び請求項１～４のいずれかに記載の非水電解質二次電池の電極用バインダーを含む、非水電解質二次電池用電極。 An electrode for a nonaqueous electrolyte secondary battery comprising an active material, a conductive additive, and a binder for an electrode of the nonaqueous electrolyte secondary battery according to any one of claims 1 to 4.
  6. 　請求項５に記載の非水電解質二次電池用電極を備える、非水電解質二次電池。 A nonaqueous electrolyte secondary battery comprising the electrode for a nonaqueous electrolyte secondary battery according to claim 5.
  7. 　請求項６に記載の非水電解質二次電池を備える電気機器。 Electrical equipment comprising the nonaqueous electrolyte secondary battery according to claim 6.
  8. 　（メタ）アクリル酸と、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルとを共重合させたアルキル変性カルボキシル基含有共重合体の、非水電解質二次電池の電極用バインダーとしての使用。 For an electrode of a non-aqueous electrolyte secondary battery, an alkyl-modified carboxyl group-containing copolymer obtained by copolymerizing (meth) acrylic acid and a (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms Use as a binder.
  9. 　（メタ）アクリル酸と、アルキル基の炭素数が１８～２４である（メタ）アクリル酸アルキルエステルとを共重合させたアルキル変性カルボキシル基含有共重合体と、活物質と、導電助剤とを含む電極用合剤スラリーを集電体に塗布する工程を備える、非水電解質二次電池用電極の製造方法。 An alkyl-modified carboxyl group-containing copolymer obtained by copolymerizing (meth) acrylic acid and a (meth) acrylic acid alkyl ester having an alkyl group having 18 to 24 carbon atoms, an active material, and a conductive auxiliary agent. The manufacturing method of the electrode for nonaqueous electrolyte secondary batteries provided with the process of apply | coating the electrode mixture slurry containing to a collector.
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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017130940A1 (en) * 2016-01-29 2017-08-03 東亞合成株式会社 Binder for nonaqueous electrolyte secondary battery electrodes, method for producing same and use of same
EP3322009A4 (en) * 2015-07-09 2018-12-12 Sumitomo Seika Chemicals Co. Ltd. Binder for lithium ion secondary battery positive electrodes
WO2019116964A1 (en) * 2017-12-15 2019-06-20 日本ゼオン株式会社 Binder composition for all-solid secondary battery, slurry composition for all-solid secondary battery, functional layer for all-solid secondary battery, and all-solid secondary battery
CN111087518A (en) * 2019-11-29 2020-05-01 合肥国轩高科动力能源有限公司 Water-based binder, preparation method thereof and lithium ion battery
JP2020102421A (en) * 2018-12-25 2020-07-02 関西ペイント株式会社 Conductive paste for all-solid secondary battery electrode and all-solid secondary battery
CN111406331A (en) * 2017-12-01 2020-07-10 昭和电工株式会社 Method for producing slurry for nonaqueous battery electrode
CN112103509A (en) * 2020-08-20 2020-12-18 欣旺达电动汽车电池有限公司 Positive current collector, positive plate, lithium ion battery and battery module

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111095636B (en) 2017-12-21 2023-06-23 松下控股株式会社 Negative electrode for nonaqueous electrolyte secondary battery and nonaqueous electrolyte secondary battery

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62160656A (en) * 1986-01-08 1987-07-16 Nippon Telegr & Teleph Corp <Ntt> Manufacture of positive electrode for nonaqueous electrolyte battery
JP2003017063A (en) * 2001-06-28 2003-01-17 Matsushita Electric Ind Co Ltd Non-sintered nickel positive electrode for alkaline storage battery, and its manufacturing method
JP2010049874A (en) * 2008-08-20 2010-03-04 Toyo Ink Mfg Co Ltd Composition for battery
JP2012124028A (en) * 2010-12-08 2012-06-28 Sumitomo Seika Chem Co Ltd Gelator for alkaline battery electrolyte
JP2012134129A (en) * 2010-11-29 2012-07-12 Sumitomo Chemical Co Ltd Electrode mixture paste, electrode, and nonaqueous electrolytic secondary battery

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62160656A (en) * 1986-01-08 1987-07-16 Nippon Telegr & Teleph Corp <Ntt> Manufacture of positive electrode for nonaqueous electrolyte battery
JP2003017063A (en) * 2001-06-28 2003-01-17 Matsushita Electric Ind Co Ltd Non-sintered nickel positive electrode for alkaline storage battery, and its manufacturing method
JP2010049874A (en) * 2008-08-20 2010-03-04 Toyo Ink Mfg Co Ltd Composition for battery
JP2012134129A (en) * 2010-11-29 2012-07-12 Sumitomo Chemical Co Ltd Electrode mixture paste, electrode, and nonaqueous electrolytic secondary battery
JP2012124028A (en) * 2010-12-08 2012-06-28 Sumitomo Seika Chem Co Ltd Gelator for alkaline battery electrolyte

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