WO2024024949A1 - Binder composition for secondary battery, composition for electrode, electrode sheet, secondary battery, manufacturing method for said electrode sheet, and manufacturing method for said secondary battery - Google Patents

Binder composition for secondary battery, composition for electrode, electrode sheet, secondary battery, manufacturing method for said electrode sheet, and manufacturing method for said secondary battery Download PDF

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WO2024024949A1
WO2024024949A1 PCT/JP2023/027792 JP2023027792W WO2024024949A1 WO 2024024949 A1 WO2024024949 A1 WO 2024024949A1 JP 2023027792 W JP2023027792 W JP 2023027792W WO 2024024949 A1 WO2024024949 A1 WO 2024024949A1
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water
active material
group
secondary battery
binder composition
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PCT/JP2023/027792
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French (fr)
Japanese (ja)
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悟郎 森
景 河野
浩徳 水田
和博 ▲濱▼田
祥平 片岡
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富士フイルム株式会社
富士フイルム和光純薬株式会社
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/04—Carbon
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K9/00—Use of pretreated ingredients
    • C08K9/02—Ingredients treated with inorganic substances
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
    • C08L1/08—Cellulose derivatives
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/24—Homopolymers or copolymers of amides or imides
    • C08L33/26—Homopolymers or copolymers of acrylamide or methacrylamide
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/32—Carbon-based
    • H01G11/38—Carbon pastes or blends; Binders or additives therein
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/84—Processes for the manufacture of hybrid or EDL capacitors, or components thereof
    • H01G11/86—Processes for the manufacture of hybrid or EDL capacitors, or components thereof specially adapted for electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134—Electrodes based on metals, Si or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1395—Processes of manufacture of electrodes based on metals, Si or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a binder composition for secondary batteries, a composition for electrodes, an electrode sheet, and a secondary battery, and a method for manufacturing these electrode sheets and secondary batteries.
  • Secondary batteries typified by lithium ion secondary batteries, are used as a power source for portable electronic devices such as personal computers, video cameras, and mobile phones. Recently, against the backdrop of the global environmental challenge of reducing carbon dioxide emissions, they have become popular as a power source for transportation equipment such as automobiles, and as a storage device for nighttime electricity, electricity generated from natural energy, etc.
  • the electrodes (positive electrode and negative electrode) of a lithium ion secondary battery generally have an electrode active material layer (positive electrode active material layer and negative electrode active material layer), and this electrode active material layer occludes lithium ions during charging and discharging.
  • the electrode active material particles may include releasable electrode active material particles, and may also contain a conductive additive, etc., if necessary. Electrode active materials, conductive aids, etc. are so-called solid particles, and due to expansion and contraction of electrode active material particles associated with charging and discharging (intercalation and release of lithium ions) of a lithium ion secondary battery, the conductivity between solid particles is impaired. Cheap. If the conduction state is impaired, the internal resistance of the battery increases and the battery capacity decreases.
  • Patent Document 1 describes a binder composition for a lithium ion secondary battery electrode that includes a particulate polymer and a water-soluble polymer.
  • Patent Document 1 discloses that the water-soluble polymer constituting this composition contains an ethylenically unsaturated carboxylic acid monomer unit, (meth)acrylamide, N-2-dimethylaminoethyl (meth)acrylamide, N-3 - Containing one or more carboxylic acid amide monomer units selected from dimethylaminopropyl (meth)acrylamide and crosslinkable monomer units other than the above-mentioned carboxylic acid amide monomer units in specific proportions;
  • an electrode active material, and a carboxymethylcellulose salt By combining this composition, an electrode active material, and a carboxymethylcellulose salt and applying it to the electrode formation of a lithium ion secondary battery, gas generation is suppressed in the resulting lithium ion secondary battery, and lithium ion It is described that the cycle characteristics of secondary batteries are improved.
  • the volume of the negative electrode active material changes greatly during charging and discharging, and the conduction state between solid particles (electrode active material, conductive agent, etc.) adhesion) is likely to be impaired. If the conduction state is impaired due to repeated charging and discharging, the internal resistance of the battery increases and battery performance tends to deteriorate. In other words, there are restrictions on improving cycle characteristics.
  • the present inventors investigated the influence of conventional electrode binders, such as the binder described in Patent Document 1, on cycle characteristics in a secondary battery using such a silicon-based active material as a negative electrode active material. As a result, conventional binders for electrodes are unable to adequately respond to the dynamic volume changes of silicon-based active materials that occur during charging and discharging. It has become clear that it is difficult to lead students to a high level.
  • the present invention is capable of sufficiently increasing the adhesion of the resulting electrode sheet (adhesion between the negative electrode active material layer and the current collector) even when using an electrode active material that exhibits large volume changes during charging and discharging.
  • An object of the present invention is to provide a binder composition for a secondary battery and a composition for an electrode that can sufficiently improve the cycle characteristics (sufficiently extend the cycle life) of a secondary battery.
  • an object of the present invention is to provide an electrode sheet and a secondary battery using the binder composition for a secondary battery or the composition for an electrode.
  • the present inventors have conducted various studies on the chemical structure of the polymer constituting the binder, and the physical properties and shape of the binder.
  • a binder composition consisting of a combination of a water-soluble polymer (X) having a specific structure, a water-soluble compound (Y), polymer particles, and water, which exhibits a specific tensile modulus, was obtained.
  • the binder composition is controlled so that the relationship between the degree of shear strain and the storage modulus is a specific relationship. It has been found that the present invention can effectively contribute to excellent adhesion within or between layers of a secondary battery, enhance the adhesion of the electrode sheet, and sufficiently extend the cycle life of the secondary battery.
  • the present invention was completed after further studies based on these findings.
  • a binder composition for a secondary battery comprising a water-soluble polymer (X), a water-soluble compound (Y), polymer particles, and water
  • the water-soluble polymer (X) is a polymer containing a component represented by the following general formula (B-2)
  • the binder composition has a tensile modulus of 1500 to 9800 MPa, and A binder composition for secondary batteries that satisfies the following ⁇ Storage Modulus Characteristics 1>.
  • R 21 to R 23 represent a hydrogen atom, a cyano group, or an alkyl group having 1 to 6 carbon atoms
  • R 24 represents a hydrogen atom, an acyl group, a hydroxy group, a phenyl group, or a carboxy group.
  • L 21 represents a single bond, an alkylene group having 1 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom, a sulfur atom, a carbonyl group, an imino group, or a linking group combining these.
  • * indicates a binding site for incorporation into the main chain of the water-soluble polymer (X).
  • ⁇ 3> The binder composition for a secondary battery according to ⁇ 1> or ⁇ 2>, wherein the component represented by the general formula (B-2) includes a (meth)acrylamide component.
  • the water-soluble polymer (X) is a polymer further containing at least one of an acrylonitrile component, an N-vinyl-2-pyrrolidone component, and a styrene component.
  • ⁇ 5> The binder composition for a secondary battery according to any one of ⁇ 1> to ⁇ 4>, wherein the water-soluble compound (Y) contains a polysaccharide.
  • ⁇ 6> For the secondary battery according to any one of ⁇ 1> to ⁇ 5>, wherein the water-soluble compound (Y) contains at least one of carboxymethyl cellulose, cellulose nanofiber, hydroxyethyl cellulose, hydroxypropyl cellulose, and xanthan gum. Binder composition. ⁇ 7> The binder composition for a secondary battery according to any one of ⁇ 1> to ⁇ 6>, wherein the water-soluble polymer (X) has a molecular weight distribution of 5.0 or less. ⁇ 8> The binder composition for a secondary battery according to any one of ⁇ 1> to ⁇ 7>, wherein the water-soluble polymer (X) has a tensile modulus of 4000 MPa or more.
  • the polymer constituting the polymer particles is a polymer containing at least one of a conjugated diene component, an ethylenically unsaturated carboxylic acid component, a cyano group-containing ethylenic monomer component, and an aromatic vinyl monomer component.
  • ⁇ 11> The binder composition for a secondary battery according to any one of ⁇ 1> to ⁇ 10>, an active material capable of inserting and releasing metal ions belonging to Group 1 or Group 2 of the periodic table, and a conductive material.
  • ⁇ 12> The electrode composition according to ⁇ 11>, wherein the active material includes a silicon-based active material.
  • ⁇ 15> A method for producing an electrode sheet, the method comprising forming an electrode active material layer using the electrode composition according to ⁇ 11> or ⁇ 12>.
  • ⁇ 16> A method for manufacturing a secondary battery, comprising incorporating an electrode sheet obtained by the manufacturing method according to ⁇ 15> as an electrode of the secondary battery.
  • water-soluble polymer means a polymer whose solubility in water is 10 g/L-H 2 O or more at 20°C, that is, a polymer that dissolves 10 g or more in 1 liter of water at 20°C. do.
  • the solubility of the "water-soluble polymer” is preferably 100 g/L-H 2 O or more.
  • water-soluble compound refers to a compound that has a solubility in water of 10 g/L-H 2 O or more at 20°C, that is, a compound that dissolves 10 g or more in 1 liter of water at 20°C. .
  • the solubility of the "water-soluble compound” is preferably 100 g/L-H 2 O or more.
  • a numerical range expressed using " ⁇ " means a range that includes the numerical values written before and after " ⁇ " as lower and upper limits.
  • the expression of a compound, a constituent component, or a substituent is meant to include those whose structures are partially changed within the range that exhibits the effects of the present invention.
  • compounds or constituent components that are not specified as being substituted or unsubstituted may have any substituent as long as the effects of the present invention are achieved.
  • substituents e.g., groups expressed as "alkyl group,””methylgroup,””methyl,” etc.
  • linking groups e.g., "alkylene group,”"methylenegroup,””methylenegroup,” etc.
  • substituents selected from substituent group T described below.
  • substituents, etc. when there are multiple substituents or linking groups, etc. (hereinafter referred to as substituents, etc.) indicated by a specific symbol or formula, or when multiple substituents, etc. are specified at the same time, unless otherwise specified, , each substituent, etc. may be the same or different from each other. This also applies to the constituent components of the polymer.
  • each component may be contained, or two or more types of each component may be contained.
  • (meth)acrylic means one or both of acrylic and methacrylic.
  • the term "secondary battery” refers to any device in which ions pass between positive and negative electrodes via an electrolyte during charging and discharging, and energy is stored and released at the positive and negative electrodes. That is, in the present invention, the term “secondary battery” includes both a battery and a capacitor (for example, a lithium ion capacitor). From the viewpoint of energy storage capacity, the secondary battery of the present invention is preferably used for battery applications (not as a capacitor).
  • Secondary batteries can be roughly classified into aqueous secondary batteries and non-aqueous secondary batteries depending on the electrolyte used, and in the present invention, non-aqueous secondary batteries are preferred.
  • aqueous secondary battery refers to a secondary battery using an aqueous electrolyte as an electrolyte.
  • non-aqueous secondary battery includes non-aqueous electrolyte secondary batteries and all-solid-state secondary batteries.
  • a non-aqueous electrolyte secondary battery means a secondary battery using a non-aqueous electrolyte as an electrolyte.
  • non-aqueous electrolyte means an electrolyte that does not substantially contain water.
  • An electrolytic solution that does not substantially contain water means that the "non-aqueous electrolytic solution” may contain a trace amount of water as long as the effects of the present invention are not impaired.
  • the "nonaqueous electrolyte” has a water concentration of 200 ppm or less (based on mass), preferably 100 ppm or less, and more preferably 20 ppm or less. Note that it is practically difficult to make the nonaqueous electrolyte completely anhydrous, and it usually contains 1 ppm or more of water.
  • the term "all-solid secondary battery” refers to a secondary battery that uses a solid electrolyte such as an inorganic solid electrolyte or a solid polymer electrolyte without using a liquid as an electrolyte.
  • this number of carbon atoms means the number of carbon atoms in the group itself unless otherwise specified in the present invention or this specification. In other words, when this group further has a substituent, the number of carbon atoms is counted without including the number of carbon atoms of this substituent.
  • the "solid content” used when describing the content or content ratio means components other than water and the liquid medium described below.
  • the "average particle size" means the volume-based median diameter D50.
  • the binder composition for secondary batteries, the composition for electrodes, and the electrode sheet of the present invention sufficiently extend the cycle life of the resulting secondary batteries even when using electrode active materials that exhibit large volume changes during charging and discharging. can do.
  • the electrode sheet of the present invention has excellent adhesiveness.
  • the secondary battery of the present invention can achieve a sufficiently long cycle life even when using an electrode active material that exhibits a large volume change during charging and discharging. According to the method for manufacturing an electrode sheet of the present invention, the above electrode sheet of the present invention can be obtained. Moreover, according to the method for manufacturing a secondary battery of the present invention, the above-mentioned secondary battery of the present invention can be obtained.
  • FIG. 1 is a vertical cross-sectional view schematically showing the basic stacked structure of an embodiment of a secondary battery according to the present invention.
  • the binder composition for secondary batteries of the present invention (hereinafter also referred to as "the binder composition of the present invention") comprises a water-soluble polymer (X), a water-soluble compound (Y), polymer particles, and water. Contains.
  • the binder composition of the present invention is preferably used for forming members or constituent layers constituting a non-aqueous secondary battery, more preferably a non-aqueous electrolyte secondary battery.
  • the water contained in the binder composition of the present invention functions as a liquid medium.
  • the binder composition of the present invention includes the binder composition of the present invention, an electrode active material (a positive electrode active material or a negative electrode active material, together also simply referred to as "active material"), and a conductive additive.
  • an electrode composition containing the above it can be suitably used for forming an electrode active material layer (positive electrode active material layer or negative electrode active material layer) in an electrode (positive electrode or negative electrode) of a secondary battery.
  • the water-soluble polymer (X) and polymer particles contained in the binder composition of the present invention are, for example, formed by mixing the binder composition of the present invention and solid particles (electrode active material, conductive aid, etc.). It is thought that in the layer, it mainly functions as a binding agent (binder) that binds these solid particles together. It can also function as a binder that binds the current collector and solid particles.
  • the adsorption of water-soluble polymer (X) and polymer particles to solid particles and current collectors includes not only physical adsorption but also chemical adsorption (adsorption due to chemical bond formation, adsorption due to transfer of electrons, etc.).
  • the water-soluble compound (Y) contained in the binder composition of the present invention is considered to mainly function as a thickener (dispersant) in the binder composition of the present invention.
  • the tensile modulus of the binder composition of the present invention is 1500 to 9800 MPa. From the viewpoint of increasing the adhesion with the current collector and effectively suppressing the volume change of the electrode active material layer to improve the cycle characteristics, the tensile modulus of the binder composition is preferably 1600 to 8000 MPa. , 1700 to 7000 MPa is more preferable, and 1800 to 6000 MPa is still more preferable.
  • the above-mentioned tensile modulus is a value obtained by a method described in Examples described later. As shown in the Examples described later, the above tensile modulus is measured using the binder composition of the present invention as a coating film having a thickness of 0.10 mm.
  • the tensile modulus of the binder composition of the present invention can be controlled within the above range by adjusting the type, content, etc. of the water-soluble polymer (X), the water-soluble compound (Y), and the polymer particles. .
  • the binder composition of the present invention satisfies the following ⁇ Storage modulus characteristic 1>.
  • ⁇ Storage modulus characteristics 1> Carbon-coated silicon oxide in powder form with an average particle size of 1 to 10 ⁇ m and a specific surface area of 1 to 10 m 2 /g; and powdered silicon oxide with an average particle size of 15 to 25 ⁇ m and a specific surface area of 1 to 10 m 2 /g.
  • slurry refers to a dispersion composition obtained by thoroughly and uniformly mixing each component as in the mixing method of the Examples.
  • total solid content in the slurry is 52% by mass
  • total solid content in the slurry is 52% by mass
  • the solvent can be evaporated by, for example, vacuum drying or reduced pressure.
  • the difference between the storage modulus GA' at a shear strain of 0.01% and the storage modulus GB ' at a shear strain of 10 % means the difference between the storage modulus GA ' at a shear strain of 0.01% It means the value obtained by subtracting the storage modulus G B ' at a shear strain of 10% (G A '-G B ').
  • the sufficiency of the above ⁇ Storage Modulus Characteristics 1> can be determined by strain dispersion measurement using a rheometer. Detailed measurement conditions are as described in Examples described later.
  • the average particle size (volume-based median diameter D50) of carbon-coated silicon oxide, graphite, and acetylene black used in ⁇ Storage modulus characteristics 1> above is 1 to 10 ⁇ m (volume-based median diameter D50).
  • the range is preferably 2 to 7 ⁇ m), 15 to 25 ⁇ m (preferably 17 to 22 ⁇ m) for graphite, and 30 to 40 nm (preferably 32 to 37 nm) for acetylene black.
  • the specific surface area of each of carbon-coated silicon oxide, graphite, and acetylene black used in ⁇ Storage modulus characteristics 1> is 1 to 10 m 2 /g (preferably 2 to 7 m 2 ) for carbon-coated silicon oxide.
  • binder in carbon-coated silicon oxide, graphite, and acetylene black used in ⁇ Storage Modulus Characteristics 1> above refers to powder (primary particles) and/or aggregates of primary particles (secondary particles). For example, it does not include pressed powder or granules.
  • the carbon-coated silicon oxide used in ⁇ Storage Modulus Characteristics 1> above refers to silicon oxide (SiO x (0 ⁇ x ⁇ 1.5)) with a carbon-based material supported on its surface.
  • the content of carbon element in the carbon-coated silicon oxide is in the range of 0.5 to 5% by mass (preferably 1 to 3% by mass).
  • the carbon-coated silicon oxide used in ⁇ Storage Modulus Characteristics 1> above is not doped with a metal element (for example, it is not silicon oxide coated with both a carbon coat and a metal element dope). shall be.
  • carbon-coated silicon oxide examples include, for example, carbon-coated silicon oxide powder (grade: SiO NC, average particle size: 5 ⁇ m, specific surface area: 2.6 m 2 /g) manufactured by Osaka Titanium Technology Co., Ltd., and graphite.
  • Commercially available products include, for example, massive artificial graphite powder (trade name: MAG-D, average particle size: 21 ⁇ m, specific surface area: 4 m 2 /g) manufactured by Showa Denko Materials, and commercially available acetylene black products, such as: Acetylene black manufactured by Denka Corporation (trade name: Denka Black, grade: powder, average particle size: 35 nm, specific surface area: 68 m 2 /g) can be used.
  • the difference between the storage elastic modulus G A ′ at a shear strain of 0.01% and the storage elastic modulus G B ′ at a shear strain of 10% is preferably 100 to 800 Pa, and 100 It is more preferably from 110 to 400 Pa, even more preferably from 120 to 300 Pa.
  • the difference in storage modulus ( GA' - GB ') of the binder composition of the present invention can be determined by adjusting the types, contents, etc. of the water-soluble polymer (X), water-soluble compound (Y), and polymer particles. By doing so, it can be kept within the above range. From the viewpoint of improving the dispersibility of solid particles, it is preferable that the difference in storage modulus is large.
  • the storage modulus G A ′ of the binder composition of the present invention at a shear strain of 0.01% is not particularly limited as long as the above difference (G A ′-G B ′) is 100 to 1000 Pa, and is 101 to 1500 Pa. It is preferably 105 to 1300 Pa, more preferably 110 to 1200 Pa.
  • the storage modulus GB' at a shear strain of 10% of the binder composition of the present invention is not particularly limited as long as the above difference (G A' -G B ') is 100 to 1000 Pa , and should be 1 to 500 Pa.
  • the pressure is preferably 5 to 300 Pa, more preferably 10 to 200 Pa.
  • the binder composition of the present invention can be made into an electrode composition containing an active material and a conductive additive, and then an electrode sheet can be created, and this can be applied to an electrode of a secondary battery, so that the electrode sheet can be tightly bonded. It is possible to improve the cycle characteristics of the secondary battery. Although the reason for this is not certain, it is thought to be as follows. By controlling the degree of shear strain and storage modulus to have a specific relationship when the binder composition of the present invention is mixed with an active material and a conductive additive, the binder composition of the present invention can be used as an electrode composition.
  • solid particles such as active materials and conductive additives can be dispersed with higher uniformity, and these solid particles effectively contribute to the formation of a conductive network structure (suppressing localization of the conductive network structure).
  • This is considered to be one of the reasons for the improvement in cycle characteristics.
  • the uniform dispersion of solid molecules and the like makes it possible to increase the peel strength against the current collector.
  • the water-soluble polymer (X) interacts with solid particles, etc., and the binder composition as a whole has a predetermined tensile modulus, which causes a change in the volume of the electrode active material layer.
  • the polymer particles have a suppressive effect on solid particles and the like, and can easily and sufficiently bring out the conformability and binding ability of the polymer particles to solid particles.
  • Water-soluble polymer (X) is a polymer containing a component represented by the following general formula (B-2).
  • R 21 to R 23 represent a hydrogen atom, a cyano group, or an alkyl group having 1 to 6 carbon atoms.
  • This alkyl group having 1 to 6 carbon atoms may be linear or branched.
  • the alkyl group having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 4 carbon atoms, more preferably methyl or ethyl, and even more preferably methyl.
  • a hydrogen atom is preferable as R 21 and R 22 .
  • R23 is preferably a hydrogen atom or methyl, more preferably a hydrogen atom.
  • R24 represents a hydrogen atom, an acyl group (alkylcarbonyl group), a hydroxy group, a phenyl group, or a carboxy group.
  • alkyl group in the acyl group include the alkyl group in substituent group T described below, which may be linear or branched, and preferably has 1 to 6 carbon atoms, which can be taken as R 21 to R 23 .
  • R24 is preferably a hydrogen atom or a hydroxy group, more preferably a hydrogen atom.
  • R N represents a hydrogen atom or an alkyl group.
  • L 21 represents a linking group other than a single bond
  • the chemical formula weight of L 21 is preferably from 14 to 2,000, more preferably from 14 to 500, even more preferably from 28 to 200.
  • the alkylene group having 1 to 16 carbon atoms that L 21 may have may be linear or branched.
  • the alkylene group preferably has 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, even more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms.
  • L 21 is preferably a single bond, methylene, ethylene, propylene, 2-hydroxypropylene or butylene, more preferably a single bond or ethylene, and even more preferably a single bond.
  • * indicates a bonding site for incorporation into the main chain of the above polymer (water-soluble polymer (X)).
  • components represented by the above general formula (B-2) include (meth)acrylamide component; N-(hydroxyalkyl)(meth) such as N-(2-hydroxyethyl)(meth)acrylamide component; Acrylamide components are mentioned, (meth)acrylamide components are preferred, and acrylamide components are more preferred.
  • the number of constituent parts represented by general formula (B-2) may be one, or two or more.
  • the water-soluble polymer (X) preferably contains a (meth)acrylamide component, and more preferably contains an acrylamide component, from the viewpoint of effectively suppressing the volume change of the electrode active material layer and improving cycle characteristics. .
  • the water-soluble polymer (X) used in the present invention may contain constituent components other than those represented by the above general formula (B-2) (hereinafter referred to as "other constituents") within a range that does not impair the effects of the present invention.
  • the composition may further include a component represented by the following general formula (B-1), an acrylonitrile component, an N-vinyl-2-pyrrolidone component, and a styrene component. It will be done.
  • the other components preferably include at least one of an acrylonitrile component, an N-vinyl-2-pyrrolidone component, and a styrene component, and more preferably an acrylonitrile component.
  • R 11 to R 13 represent a hydrogen atom, a cyano group, or an alkyl group having 1 to 6 carbon atoms.
  • This alkyl group having 1 to 6 carbon atoms may be linear or branched.
  • the alkyl group having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 4 carbon atoms, more preferably methyl or ethyl, and even more preferably methyl.
  • a hydrogen atom is preferable as R 11 and R 12 .
  • R 13 is preferably a hydrogen atom or methyl, and more preferably a hydrogen atom.
  • the alkyl group in the above alkoxy group having 1 to 6 carbon atoms may be linear or branched.
  • the alkoxy group having 1 to 6 carbon atoms is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably methoxy or ethoxy.
  • R 14 is preferably a hydrogen atom, a hydroxy group, methoxy or ethoxy, and more preferably a hydrogen atom.
  • R N ' represents a hydrogen atom or an alkyl group.
  • L 11 represents a linking group other than a single bond
  • the chemical formula weight of L 11 is preferably from 14 to 2,000, more preferably from 14 to 500, even more preferably from 28 to 200.
  • the alkylene group having 1 to 16 carbon atoms that L 11 may have may be linear or branched.
  • the alkylene group preferably has 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, even more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms.
  • L 11 is preferably a single bond, methylene, ethylene, propylene, 2-hydroxypropylene, and butylene, and more preferably a single bond, ethylene, or butylene. * indicates a bonding site for incorporation into the main chain of the above polymer (water-soluble polymer (X)).
  • components represented by the above general formula (B-1) include (meth)acrylic acid component; methyl (meth)acrylate component, ethyl (meth)acrylate component, and propyl (meth)acrylate component. and alkyl (meth)acrylate components such as butyl (meth)acrylate components; 2-hydroxyethyl (meth)acrylate component, 4-hydroxybutyl (meth)acrylate component, 2,3-dihydroxypropyl (meth)acrylate component, etc.
  • hydroxyalkyl (meth)acrylate component examples include alkoxyalkyl (meth)acrylate components such as methoxyethyl (meth)acrylate component and ethoxyethyl (meth)acrylate component; Acrylate components are preferred.
  • the number of constituent components contained in the water-soluble polymer (X) is not particularly limited, and is preferably 1 to 10, more preferably 1 to 5, even more preferably 1 to 3, and one or more. Two types are particularly preferred.
  • the water-soluble polymer (X) described below polymers having one, two, or three types of constituent components are described.
  • the polymer having one type of component is polyacrylamide.
  • the content of the component represented by the above general formula (B-2) is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. , more preferably 85% by mass or more, and may be 100% by mass.
  • the content of the components represented by the above general formula (B-2) is preferably 65% by mass or more, and 75% by mass or more. More preferably, the amount is % by mass or more.
  • the content of the component represented by the above general formula (B-2) is shown as a preferable range: Preferably 60 to 95% by mass, more preferably 65 to 90% by mass, more preferably 70 to 90% by mass, more preferably 75 to 90% by mass, more preferably 80 to 90% by mass, and more preferably 85 to 90% by mass. More preferred.
  • the total content of the other constituent components is preferably 5 to 40% by mass, and 10 to 35% by mass.
  • the total content of the component represented by the above general formula (B-1), acrylonitrile component, N-vinyl-2-pyrrolidone component, and styrene component is 40% by mass or less is preferable, 30% by mass or less is more preferable, and even more preferably 20% by weight or less.
  • the weight average molecular weight (Mw) of the water-soluble polymer (X) used in the present invention is not particularly limited, and from the viewpoint of improving cycle characteristics, it is preferably 100,000 to 900,000, more preferably 200,000 to 500,000. It is preferable that the water-soluble polymer (X) does not have a crosslinked structure, that is, it is a chain polymer.
  • the molecular weight distribution of the water-soluble polymer (X) is preferably 5.0 or less, more preferably 3.0 or less. On the other hand, it is practical for the molecular weight distribution to be 1.0 or more.
  • the molecular weight distribution of the water-soluble polymer (X) is also called the degree of dispersion, and is calculated by [weight average molecular weight (Mw)]/[number average molecular weight (Mn)].
  • the weight average molecular weight and number average molecular weight of the polymer are measured by gel permeation chromatography (GPC).
  • the "molecular weight" in these weight average molecular weight and number average molecular weight refers to the molecular weight in terms of polyethylene oxide.
  • the values are basically measured according to the method of measurement condition 1 below. However, depending on the type of polymer, an appropriate eluent may be selected and used.
  • Measuring instrument HLC-8220GPC (product name, manufactured by Tosoh Corporation)
  • Carrier 200mM sodium nitrate aqueous solution Measurement temperature: 40°C Carrier flow rate: 1.0ml/min Sample concentration: 0.2% by mass Detector: RI (refractive index) detector If the molecular weight cannot be measured under measurement condition 1 above, such as when crosslinking occurs, the molecular weight is measured by static light scattering under measurement condition 2 below.
  • RI reffractive index
  • the water-soluble polymer (X) used in the present invention preferably has a tensile modulus of 3500 MPa or more, preferably 4000 MPa or more, from the viewpoint of effectively suppressing the volume change of the electrode active material layer and improving cycle characteristics. is more preferable, 5000 MPa or more is still more preferable, and 6000 MPa or more is particularly preferable. On the other hand, it is practical for the tensile modulus to be 15,000 MPa or less.
  • the tensile modulus of the water-soluble polymer (X) is preferably 3,500 to 15,000 MPa, more preferably 4,000 to 15,000 MPa, more preferably 5,000 to 15,000 MPa, and more preferably 6,000 to 15,000 MPa. preferable.
  • the above tensile modulus is determined by using an aqueous solution of water-soluble polymer (X) in place of the binder composition of the present invention in a tensile modulus test of the binder composition of the present invention described in the Examples described below. Other than this, the value is obtained by the same method as the tensile modulus test of the binder composition of the present invention described above.
  • the water-soluble polymer (X) may further have a substituent in each structure or partial structure described above, and examples of the substituent include substituents selected from the substituent group T below.
  • Substituent group T - Alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, such as methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), Alkenyl group (preferably an alkenyl group having 2 to 20 carbon atoms, such as vinyl, allyl, oleyl, etc.), alkynyl group (preferably an alkynyl group having 2 to 20 carbon atoms, such as ethynyl, butadiynyl, phenylethynyl) etc.), cycloalkyl groups (preferably cycloalkyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.),
  • sulfamoyl (-SO 2 NH 2 ), N,N-dimethylsulfamoyl, N-phenylsulfamoyl, etc.), acyl groups (alkylcarbonyl group, alkenylcarbonyl group, alkynylcarbonyl group, arylcarbonyl group, and heterocycle) Acyl group containing a carbonyl group and preferably having 1 to 20 carbon atoms, such as formyl, acetyl, propionyl, butyryl, octanoyl, hexadecanoyl, acryloyl, methacryloyl, crotonoyl, benzoyl, naphthoyl, nicotinoyl, etc.), acyloxy group (Including alkylcarbonyloxy groups, alkenylcarbonyloxy groups, alkynylcarbonyloxy groups, arylcarbonyloxy groups and heterocyclic carbony
  • the acyl group in the acylamino group is preferably the above-mentioned acyl group.
  • acetylamino, benzoylamino, etc. an alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms, For example, methylthio, ethylthio, isopropylthio, benzylthio, etc.), arylthio group (preferably an arylthio group having 6 to 26 carbon atoms, such as phenylthio, 1-naphthylthio, 3-methylphenylthio, 4-methoxyphenylthio, etc.) , an arylsilyl group (preferably an arylsilyl group having 6 to 42 carbon atoms, such as triphenylsilyl), a heterocyclic thio group (a group in which an -S- group is bonded to the above heterocyclic group), an alkylsulfonyl
  • the water-soluble polymer (X) used in the present invention can be obtained by a conventional polymer synthesis method.
  • the methods and conditions for chain polymerization etc. are not particularly limited, and conventional methods and conditions can be appropriately applied depending on the purpose.
  • the "water solubility" of the water-soluble polymer (X) can be controlled, for example, by the types of constituent components and their contents.
  • the water-soluble polymer (X) may be used alone or in combination of two or more.
  • the water-soluble compound (Y) is a water-soluble compound (monomer or polymer) having a different structure from the water-soluble polymer (X) described above, and is A wide variety of agents that function as thickeners for forming slurries can be used.
  • the thickener include cellulose compounds and polysaccharides such as natural polysaccharides.
  • cellulose compounds include methylcellulose, ethylcellulose, benzylcellulose, triethylcellulose, cyanoethylcellulose, nitrocellulose, hydroxymethylcellulose, hydroxyethylcellulose (HEC), hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC), hydroxybutylmethylcellulose, carboxy Examples include methylcellulose (CMC), aminomethylhydroxypropylcellulose, aminoethylhydroxypropylcellulose, cellulose nanofiber (CNF), and cellulose nanocrystal (CNC). Further, the cellulose compound may be in the form of a salt such as an ammonium salt, a sodium salt, or a lithium salt.
  • a salt such as an ammonium salt, a sodium salt, or a lithium salt.
  • the water-soluble compound (Y) preferably contains at least one of carboxymethyl cellulose, cellulose nanofibers, hydroxyethyl cellulose, hydroxypropyl cellulose, and xanthan gum.
  • the water-soluble compound (Y) may be used alone or in combination of two or more.
  • polymer particles The polymer particles used in the present invention are particulate polymers, and "particulate” may be flat, amorphous, etc., and preferably spherical or granular. Note that the polymer particles are water-insoluble polymers. That is, the polymer particles are polymers whose solubility in water at 20° C. is less than 10 g/L-H 2 O (not more than 10 g per 1 liter of water).
  • the tensile modulus of the polymer particles is not particularly limited, and is preferably 100 to 3000 MPa from the viewpoint of improving the adhesion between solid particles or between a current collector and solid particles to improve the adhesion and cycle characteristics of the electrode sheet. , 100 to 1000 MPa is more preferable.
  • the above-mentioned tensile modulus is determined by using polymer particles (latex polymer) in place of the binder composition of the present invention in the tensile modulus test of the binder composition of the present invention described in the Examples described below. is a value obtained by the same method as the tensile modulus test of the binder composition of the present invention described above.
  • the glass transition temperature of the polymer particles is not particularly limited, and from the viewpoint of improving the adhesion and cycle characteristics of the electrode sheet, it is preferably -50 to 150°C, more preferably -30 to 100°C. In addition, when a polymer particle has two or more glass transition temperatures, it is preferable that all of them fall within the above-mentioned preferable range.
  • the glass transition temperature of the polymer particles is the value listed in the manufacturer's catalog.
  • the glass transition temperature in the table in Chapter 36 of the literature POLYMER HANDBOOK 4th is adopted. If the glass transition temperature is not described in the above literature, the glass transition temperature obtained by measurement under the following measurement conditions is employed.
  • the glass transition temperature (Tg) is calculated by measuring a dry sample of polymer particles using a differential scanning calorimeter: X-DSC7000 (trade name, manufactured by SII Nano Technology Co., Ltd.) under the following measurement conditions. Measurements are performed twice on the same sample, and the results of the second measurement are used.
  • Tg is calculated by rounding off the decimal point of the intermediate temperature between the start point and end point of the drop on the DSC (differential scanning calorimetry) chart.
  • the average particle size (average primary particle size) of the polymer particles is not particularly limited, and is preferably from 50 to 300 nm, more preferably from 50 to 250 nm, even more preferably from 50 to 200 nm.
  • the average particle diameter of the polymer particles is the value listed in the manufacturer's catalog.
  • the average particle size of the polymer particles is the average particle size of the negative electrode active material (volume-based median diameter D50 in water) of the negative electrode active material described below. ) may be used.
  • the polymer particles may be either sequential polymer particles or chain polymer particles, and chain polymer particles are preferred.
  • the chain polymer particles may be homopolymers or copolymers.
  • the polymerization form of the copolymer may be either random or block.
  • Constituent components of the polymer particles (chain polymerization polymer) include, for example, a conjugated diene component, an aromatic vinyl monomer component, an ethylenically unsaturated carboxylic acid component, a cyano group-containing ethylenic monomer component, and an ethylenically unsaturated carboxylic acid ester component.
  • the polymer particles have a conjugated diene component and an aromatic vinyl monomer component among the above components.
  • the aromatic vinyl monomer component means a component derived from a monomer having a carbon-carbon double bond (preferably one or two, more preferably one) and an aryl group (preferably one).
  • the ethylenically unsaturated carboxylic acid component means a component derived from a monomer having a carbon-carbon double bond (preferably one) and a carboxy group (preferably one or two), and contains a cyano group.
  • the ethylenic monomer component means a component derived from a monomer having a carbon-carbon double bond (preferably one) and a cyano group (preferably one or two, more preferably one);
  • the unsaturated carboxylic acid ester component means a component derived from a monomer having a carbon-carbon double bond (preferably one) and a carboxylic acid ester moiety (esterified carboxy group) (preferably one).
  • the fluorinated vinyl monomer component means an ethylene-derived component having 1 to 4 (preferably 2) fluorine atoms. Note that the above-mentioned "carbon-carbon double bond" does not include the carbon-carbon double bond of an aromatic ring.
  • conjugated diene leading to the conjugated diene component examples include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, and 2-chloro-1,3 - Aliphatic conjugated dienes such as butadiene.
  • aromatic vinyl monomer leading to the aromatic vinyl monomer component examples include styrene, ⁇ -methylstyrene, 4-tert-butylstyrene, 4-tert-butoxystyrene, and vinyltoluene (3-vinyltoluene, 4-vinyltoluene).
  • Examples of the ethylenically unsaturated carboxylic acid leading to the ethylenically unsaturated carboxylic acid component include (meth)acrylic acid, maleic acid, itaconic acid, and fumaric acid.
  • Examples of the cyano group-containing ethylenic monomer leading to the cyano group-containing ethylenic monomer component include (meth)acrylonitrile, ⁇ -chloroacrylonitrile, ⁇ -ethyl acrylonitrile, and vinylidene cyanide.
  • Examples of the ethylenically unsaturated carboxylic ester that leads to the ethylenically unsaturated carboxylic ester component include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, Examples include alkyl (meth)acrylates such as hexyl (meth)acrylate, octyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.
  • Examples of the vinyl fluoride monomer leading to the vinyl fluoride monomer component include vinylidene fluoride.
  • the polymer particles used in the present invention can be obtained by conventional polymer synthesis methods.
  • the methods and conditions for chain polymerization etc. are not particularly limited, and conventional methods and conditions can be appropriately applied depending on the purpose.
  • the polymer particles may be particles obtained by performing a modification treatment such as carboxy modification on the above-mentioned sequential polymer particles and chain polymer particles.
  • the method and conditions for the modification treatment are not particularly limited, and can be carried out by conventional methods.
  • the water solubility, tensile modulus, glass transition temperature, and average particle size of the polymer particles can be adjusted, for example, by adjusting the types and contents of the constituent components in the polymer.
  • polymer particles include styrene/butadiene copolymers, acrylic polymers, and poly(vinylidene fluoride), with styrene/butadiene copolymers being preferred.
  • the styrene/butadiene copolymer means a copolymer having the above-mentioned aromatic vinyl monomer component and the above-mentioned conjugated diene component, and may be a modified copolymer such as a carboxy-modified copolymer.
  • one type of polymer particles may be used alone, or two or more types may be used in combination.
  • the binder composition of the present invention may contain other polymers commonly used as binders for batteries.
  • the total proportion of the water-soluble polymer (X), the water-soluble compound (Y), and the polymer particles in all the solid content contained in the binder composition of the present invention is preferably 80% by mass or more, and 90% by mass.
  • the content is more preferably 95% by mass or more, even more preferably 99% by mass or more.
  • all solid components contained in the binder composition of the present invention are water-soluble polymer (X), water-soluble compound (Y), and polymer particles.
  • the mass ratio of the water-soluble polymer (X), the water-soluble compound (Y), and the polymer particles mass of the water-soluble polymer (X): of the water-soluble compound (Y)) Mass: mass of polymer particles
  • mass ratio of the water-soluble polymer (X), the water-soluble compound (Y), and the polymer particles mass of polymer particles
  • mass ratio of the water-soluble polymer (X): of the water-soluble compound (Y)) Mass: mass of polymer particles is not particularly limited, and is preferably 10-80:3-80:10-77, more preferably 20-70:3-50:20-60.
  • the binder composition of the present invention contains water as a liquid medium.
  • the content of water in the binder composition of the present invention is not particularly limited, and can be, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more. It can be at least 50% by mass, particularly preferably at least 50% by mass.
  • the binder composition of the present invention may contain water in an amount of 60% by mass or more, 70% by mass or more, or 80% by mass or more. On the other hand, it is practical for the content of water in the binder composition of the present invention to be 99.5% by mass or less.
  • the content of water in the binder composition of the present invention can be 99% by mass or less, 95% by mass or less, and 90% by mass or less.
  • the content of water in the binder composition of the present invention can be, for example, 10 to 99.5% by mass, preferably 20 to 99% by mass, more preferably 30 to 99% by mass, and more preferably,
  • the content is 40 to 99% by weight, more preferably 50 to 99% by weight, more preferably 60 to 99% by weight, more preferably 70 to 95% by weight, and more preferably 80 to 90% by weight.
  • the binder composition of the present invention may contain a liquid medium other than water.
  • liquid media other than water examples include organic solvents that mix with water without phase separation (hereinafter referred to as water-soluble organic solvents), such as N-methylpyrrolidone, methanol, ethanol, and acetone. , tetrahydrofuran, etc. are preferably mentioned.
  • water-soluble organic solvents such as N-methylpyrrolidone, methanol, ethanol, and acetone. , tetrahydrofuran, etc. are preferably mentioned.
  • the contents of the water-soluble polymer (X), the water-soluble compound (Y), and the polymer particles may be appropriately set depending on the purpose.
  • the total content of the water-soluble polymer (X), water-soluble compound (Y), and polymer particles in the binder composition can be 0.5 to 50% by mass, preferably 5 to 30% by mass. %, more preferably 10 to 20% by mass.
  • the binder composition of the present invention may contain other components depending on the purpose in addition to the water-soluble polymer (X), the water-soluble compound (Y), the polymer particles, water, and a liquid medium other than water. Can be done. Examples of other components include polyhydric alcohols (alcohols having two or more hydroxy groups).
  • the binder composition of the present invention can also be prepared by diluting a synthetic solution of the water-soluble polymer (X), the water-soluble compound (Y), and the polymer particles. Therefore, even if the binder composition of the present invention contains the water-soluble polymer (X), the water-soluble compound (Y), the compound used in the synthesis of the polymer particles, or the by-product after the reaction, good.
  • the binder composition of the present invention can be applied to either a positive electrode or a negative electrode composition, it is preferably used for a negative electrode, and particularly preferably used for a negative electrode composition containing a silicon-based active material.
  • the electrode composition of the present invention comprises the binder composition of the present invention and an active material (hereinafter also simply referred to as "active material") capable of inserting and releasing ions of metals belonging to Group 1 or Group 2 of the periodic table. ) and a conductive aid. That is, the electrode composition of the present invention is a composition containing a water-soluble polymer (X), a water-soluble compound (Y), polymer particles, water, an active material, and a conductive aid. It is preferable that the tensile modulus of the remainder of the electrode composition of the present invention after removing the above-mentioned active material and the above-mentioned conductive support agent is 1500 to 9800 MPa.
  • the remainder after removing the active material and the conductive aid from the electrode composition of the present invention corresponds to the "binder composition of the present invention," and its composition is the same as that of the binder composition of the present invention.
  • the tensile modulus of the remainder of the electrode composition of the present invention after removing the active material and the conductive aid corresponds to the "tensile modulus of the binder composition of the present invention," and the test method and its The preferred range is similar to the tensile modulus of the binder composition of the present invention.
  • the active material may be a positive electrode active material or a negative electrode active material.
  • the electrode composition of the present invention contains a positive electrode active material
  • the electrode composition of the present invention can be used as a slurry for forming a positive electrode active material layer of a secondary battery.
  • the electrode composition of the present invention contains a negative electrode active material
  • the electrode composition of the present invention can be used as a slurry for forming a negative electrode active material layer.
  • the above-mentioned electrode composition of the present invention can be applied to either a positive electrode or a negative electrode composition, but it is preferably used as a negative electrode composition, and especially a negative electrode composition containing a silicon-based active material. It is preferable to use it as
  • the electrode composition of the present invention can further contain other additives as necessary.
  • the active material, conductive aid, and other additives are not particularly limited, and may be appropriately selected from those commonly used in secondary batteries depending on the purpose.
  • the content of the water-soluble polymer (X), the water-soluble compound (Y), and the polymer particles in the electrode composition of the present invention is not particularly limited, and the total content is from 0.5 to 0.5 based on the total solid content. It is preferably 30% by weight, more preferably 1.0 to 20% by weight, even more preferably 1.5 to 15% by weight, and particularly preferably 2.5 to 10% by weight.
  • the mass ratio of the water-soluble polymer (X), the water-soluble compound (Y), and the polymer particles mass of the water-soluble polymer (X): water-soluble compound (Y) mass of polymer particles
  • the mass ratio of the water-soluble polymer (X): water-soluble compound (Y) mass of polymer particles is the same as their mass ratio in the binder composition of the present invention.
  • the water content is preferably 30 to 70% by mass, more preferably 40 to 60% by mass, and even more preferably 45 to 55% by mass.
  • the electrode composition of the present invention contains water derived from the binder composition of the present invention, and further contains water added at the time of preparing the electrode composition. may contain water.
  • the solid content is preferably 30 to 70% by mass, more preferably 40 to 60% by mass, and even more preferably 45 to 55% by mass.
  • the total proportion of the water-soluble polymer (X), water-soluble compound (Y), polymer particles, active material, and conductive aid in all the solid content contained in the electrode composition of the present invention is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more. Moreover, it is most preferable that all of the solid components contained in the electrode composition of the present invention are the water-soluble polymer (X), the water-soluble compound (Y), the polymer particles, the active material, and the conductive additive. .
  • the difference ( G C' -G D ') is preferably between 100 and 1000 Pa. This makes it easier for the electrode composition to enjoy the effects of improving the uniform dispersibility of solid particles, followability to solid particles, binding properties, etc., by the binder composition of the present invention. As a result, it becomes possible to further improve the adhesion of the electrode sheet obtained using the electrode composition of the present invention, and to further improve the cycle characteristics of the secondary battery.
  • the storage elastic modulus GC ' at a shear strain of 0.01% and the storage elastic modulus GD ' at a shear strain of 10% can be measured using a rheometer.
  • the measurement can be performed under the same measurement conditions except that the electrode composition of the present invention is used in place of the measurement slurry.
  • "Storage modulus GC ' at 0.01% shear strain”, “Storage modulus GD ' at 10% shear strain”, “Storage modulus G at 0.01% shear strain” in the electrode composition of the present invention Difference between C ' and storage modulus G D ' at 10% shear strain (G C '-G D ')'' are the above-mentioned 'storage modulus G A ' at shear strain 0.01%' and '"Storage modulus G B ' at 10% shear strain", "difference between storage modulus G A' at shear strain 0.01% and storage modulus G B ' at 10% shear strain (G A '-G B ' )” can be applied.
  • the electrode composition of the present invention contains an active material capable of intercalating and ejecting metal ions belonging to Group 1 or Group 2 of the periodic table.
  • the positive electrode active material is an active material capable of inserting and extracting ions of metals belonging to Group 1 or Group 2 of the periodic table, and among them, a material that can reversibly insert and release lithium ions is preferable.
  • the material is not particularly limited as long as it has the above characteristics; 1) transition metal oxides, 2) organic substances, 3) elements that can be complexed with Li such as sulfur, 4) composites of sulfur and metals. etc. may be used.
  • it is preferable to use a transition metal oxide as the positive electrode active material and a transition metal oxide containing a transition metal element M a (one or more elements selected from Co, Ni, Fe, Mn, Cu, and V) is preferable. more preferable.
  • this transition metal oxide contains elements M b (metal elements of group 1 (Ia) of the periodic table other than lithium, elements of group 2 (IIa) of the periodic table, Al, Ga, In, Ge, Sn, Pb, Elements such as Sb, Bi, Si, P, or B may be mixed.
  • the mixing amount of element M b is preferably 0 to 30 mol % with respect to 100 mol % of transition metal element M a . It is more preferable to synthesize Li by mixing the transition metal element M a with a molar ratio (Li/M a ) of 0.3 to 2.2.
  • transition metal oxides include (MA) transition metal oxides having a layered rock salt structure, (MB) transition metal oxides having a spinel structure, (MC) lithium-containing transition metal phosphate compounds, (MD ) Lithium-containing transition metal halide phosphoric acid compounds and (ME) lithium-containing transition metal silicate compounds.
  • transition metal oxides having a layered rock salt type structure include LiCoO 2 (lithium cobalt oxide [LCO]), LiNi 2 O 2 (lithium nickel oxide), LiNi 0.85 Co 0.10 Al 0. 05 O 2 (nickel cobalt lithium aluminate [NCA]), LiNi 1/3 Co 1/3 Mn 1/3 O 2 (nickel manganese cobalt lithium [NMC]), and LiNi 0.5 Mn 0.5 O 2 ( lithium manganese nickelate).
  • LiCoO 2 lithium cobalt oxide [LCO]
  • LiNi 2 O 2 lithium nickel oxide
  • LiNi 0.85 Co 0.10 Al 0. 05 O 2 nickel cobalt lithium aluminate [NCA]
  • LiNi 1/3 Co 1/3 Mn 1/3 O 2 nickel manganese cobalt lithium [NMC]
  • LiNi 0.5 Mn 0.5 O 2 lithium manganese nickelate
  • transition metal oxides having a spinel structure include LiMn 2 O 4 (LMO), LiCoMnO 4 , Li 2 FeMn 3 O 8 , Li 2 CuMn 3 O 8 , Li 2 CrMn 3 O 8 and Li 2NiMn3O8 is mentioned .
  • LMO LiMn 2 O 4
  • MC lithium-containing transition metal phosphate compounds
  • iron pyrophosphates such as LiFeP 2 O 7 , LiCoPO 4 , etc.
  • lithium-containing transition metal halide phosphate compounds include iron fluorophosphates such as Li 2 FePO 4 F, manganese fluorophosphates such as Li 2 MnPO 4 F, and Li 2 CoPO 4 F.
  • Examples include cobalt fluorophosphate salts such as.
  • ME Examples of the lithium-containing transition metal silicate compound include Li 2 FeSiO 4 , Li 2 MnSiO 4 and Li 2 CoSiO 4 .
  • (MA) transition metal oxides having a layered rock salt type structure are preferred, and LCO or NMC is more preferred.
  • the shape of the positive electrode active material is not particularly limited, and a particulate shape is preferable.
  • the average particle diameter (volume-based median diameter D50) of the positive electrode active material is not particularly limited. For example, it can be 0.1 to 50 ⁇ m.
  • it may be prepared by a conventional method using a pulverizer or a classifier. A method for preparing a negative electrode active material to a predetermined particle size, which will be described later, can also be applied.
  • the positive electrode active material obtained by the calcination method may be used after being washed with water, an acidic aqueous solution, an alkaline aqueous solution, an organic solvent, or the like.
  • the average particle size of the cathode active material should be the value listed in the manufacturer's catalog. If information on the manufacturer's average particle size is not available or when using a synthesized cathode active material, The value measured and calculated by the method described in the negative electrode active material described below is adopted.
  • the chemical formula of the compound obtained by the above firing method can be calculated using inductively coupled plasma (ICP) emission spectrometry as a measurement method, or from the difference in mass of the powder before and after firing as a simple method.
  • ICP inductively coupled plasma
  • the surface of the positive electrode active material may be coated with another oxide such as a metal oxide, a carbon-based material, or the like.
  • a surface coating material that can be used for surface coating of a negative electrode active material, which will be described later, can be used.
  • the surface of the positive electrode active material may be surface-treated with sulfur or phosphorus.
  • the particle surface of the positive electrode active material may be surface-treated with active light or active gas (plasma, etc.) before and after the surface coating.
  • the above positive electrode active materials may be used alone or in combination of two or more.
  • the mass (mg) (basis weight) of the positive electrode active material per unit area (cm 2 ) of the positive electrode active material layer is not particularly limited. It can be determined as appropriate depending on the designed battery capacity.
  • the content of the positive electrode active material in the electrode composition of the present invention is not particularly limited, and is preferably 10 to 99% by mass, more preferably 30 to 98% by mass, and 50 to 97% by mass based on the total solid content. % is more preferable, and 55 to 95% by weight is particularly preferable.
  • the negative electrode active material is an active material capable of intercalating and deintercalating ions of metals belonging to Group 1 or Group 2 of the periodic table, and among them, a material capable of reversibly intercalating (occluding) and deintercalating lithium ions is preferable.
  • the material is not particularly limited as long as it has the above characteristics, such as carbonaceous materials, silicon-based materials (meaning materials containing the silicon element), tin-based materials (meaning the materials containing the tin element). ), metal oxides, metal composite oxides, simple lithium, lithium alloys, etc. Among these, carbonaceous materials or silicon-based materials are preferably used from the viewpoint of reliability.
  • the carbonaceous material used as the negative electrode active material is a material consisting essentially of carbon.
  • Examples include petroleum pitch, carbon black such as acetylene black, graphite (natural graphite such as flaky graphite and lumpy graphite, artificial graphite such as vapor-grown graphite and fibrous graphite, expanded graphite made by specially processing flaky graphite, etc.) ), activated carbon, carbon fiber, coke, soft carbon, hard carbon, and carbonaceous materials obtained by firing various synthetic resins such as PAN (polyacrylonitrile) resin or furfuryl alcohol resin.
  • PAN polyacrylonitrile
  • various carbon fibers such as PAN carbon fiber, cellulose carbon fiber, pitch carbon fiber, vapor grown carbon fiber, dehydrated PVA (polyvinyl alcohol) carbon fiber, lignin carbon fiber, glassy carbon fiber, and activated carbon fiber. Mention may also be made of mesophase microspheres, graphite whiskers, and tabular graphite.
  • the metal oxides and metal composite oxides used as negative electrode active materials are those that can intercalate and deintercalate (preferably intercalate and deintercalate) metal ions (preferably lithium ions) belonging to Group 1 or Group 2 of the periodic table.
  • metal oxides include oxides of metal elements (metal oxides) and oxides of metalloid elements (metalloid oxides)
  • metal composite oxides include Examples include composite oxides of metal elements, composite oxides of metal elements and metalloid elements, and composite oxides of metalloid elements.
  • amorphous oxides are preferable, and chalcogenite, which is a reaction product of a metal element and an element of Group 16 of the periodic table, is also preferably mentioned.
  • chalcogenite which is a reaction product of a metal element and an element of Group 16 of the periodic table.
  • the term "amorphous” as used herein means that it has a broad scattering band with a peak in the 2 ⁇ value range of 20° to 40°, as determined by X-ray diffraction using CuK ⁇ rays, and the crystalline diffraction line It may have.
  • the amorphous oxides of metalloid elements or the above-mentioned chalcogenides are more preferable, and elements of groups 13 (IIIB) to 15 (VB) of the periodic table are preferred.
  • Particularly preferred are oxides or composite oxides, or chalcogenides consisting of one of the following (for example, Al, Ga, Si, Sn, Ge, Pb, Sb, and Bi) or a combination of two or more thereof.
  • amorphous oxides and chalcogenides include, for example, Ga 2 O 3 , GeO, PbO, PbO 2 , Pb 2 O 3 , Pb 2 O 4 , Pb 3 O 4 , Sb 2 O 3 , Sb 2 O 4 , Sb2O8Bi2O3 , Sb2O8Si2O3 , Sb2O5 , Bi2O3 , Bi2O4 , GeS , PbS , PbS2 , Sb2S3 and Sb2S 5 is preferred.
  • the metal (composite) oxide and the chalcogenide preferably contain at least one of titanium and lithium as a constituent from the viewpoint of high current density charge/discharge characteristics.
  • the metal composite oxide containing lithium (lithium composite metal oxide) is, for example, a composite oxide of lithium oxide and the above metal (composite) oxide or the above chalcogenide, more specifically, Li 2 SnO 2 Can be mentioned.
  • the negative electrode active material contains titanium element. More specifically, TiNb 2 O 7 (niobium titanate oxide [NTO]) and Li 4 Ti 5 O 12 (lithium titanate [LTO]) have small volume fluctuations when lithium ions are absorbed and released, so they are suitable for rapid charging. It is preferable because it has excellent discharge characteristics, suppresses electrode deterioration, and makes it possible to improve the cycle characteristics of a lithium ion secondary battery.
  • NTO niobium titanate oxide
  • Li 4 Ti 5 O 12 lithium titanate [LTO]
  • the lithium alloy as a negative electrode active material is not particularly limited as long as it is an alloy commonly used as a negative electrode active material of secondary batteries, and examples thereof include lithium aluminum alloys.
  • the silicon-based material is a negative electrode active material containing the silicon element, such as silicon materials such as Si and SiOx (0 ⁇ x ⁇ 1.5), as well as titanium, vanadium, chromium, Silicon-containing alloys containing manganese, nickel, copper or lanthanum (e.g. LaSi 2 , VSi 2 ) or structured active materials (e.g. LaSi 2 /Si), as well as the metal oxides and metal composite oxides mentioned above. Examples include oxides or composite oxides containing silicon elements in the description of products, and active materials containing silicon elements and tin elements such as SnSiO 3 and SnSiS 3 . SiOx itself can be used as a negative electrode active material (semi-metal oxide), and since Si is generated during battery operation, it can be used as an active material (its precursor material) that can form an alloy with lithium. Can be done.
  • silicon materials such as Si and SiOx (0 ⁇ x ⁇ 1.5)
  • the negative electrode active material is preferably a negative electrode active material that can form an alloy with lithium.
  • the negative electrode active material capable of forming an alloy with lithium is not particularly limited as long as it is commonly used as a negative electrode active material of secondary batteries. Examples of such active materials include negative electrode active materials containing the silicon element and/or tin element described above, and metals such as Al and In.
  • a silicon-based active material is preferable in that it enables higher battery capacity, and a silicon-based active material in which the content of silicon element is 40 mol % or more of all constituent elements is more preferable.
  • negative electrodes containing negative electrode active materials that can be alloyed with lithium are different from negative electrodes made only of carbonaceous materials ( It can store more Li ions than graphite, carbon black, etc.). That is, the amount of Li ions stored per unit mass increases. Therefore, battery capacity (energy density) can be increased. As a result, there is an advantage that the battery operating time can be extended.
  • a negative electrode active material that can form an alloy with lithium such as a negative electrode active material containing a silicon element and/or a tin element, is also referred to as a high-capacity active material.
  • the surface of the negative electrode active material may be coated with an oxide such as another metal oxide, a carbon-based material, etc. (hereinafter, surface coating with a carbon-based material is referred to as "carbon-coated”).
  • an oxide such as another metal oxide, a carbon-based material, etc.
  • surface coating with a carbon-based material is referred to as "carbon-coated”).
  • the surface coating material include metal oxides containing Ti, Nb, Ta, W, Zr, Al, Si, or Li.
  • lithium niobate compounds include spinel titanate, tantalum oxides, niobium oxides, lithium niobate compounds, and more specifically, Li 4 Ti 5 O 12 , Li 2 Ti 2 O 5 , LiTaO 3 , LiNbO3 , LiAlO2 , Li2ZrO3 , Li2WO4 , Li2TiO3 , Li2B4O7 , Li3PO4 , Li2MoO4 , Li3BO3 , LiBO2 , Li2 Examples include CO 3 , Li 2 SiO 3 , SiO 2 , TiO 2 , ZrO 2 , Al 2 O 3 and B 2 O 3 . Further, carbon-based materials such as C, SiC, and carbon-doped silicon oxide can also be used as surface coating materials.
  • the surface of the negative electrode active material may be surface-treated with sulfur or phosphorus.
  • the particle surface of the negative electrode active material may be surface-treated with active light or active gas (plasma, etc.) before and after the surface coating.
  • the negative electrode active material may be doped with a metal element.
  • the metal element to be doped is preferably at least one of Li, Ni, and Ti, and more preferably Li.
  • a silicon-based active material as the negative electrode active material, and silicon oxide (SiO x (0 ⁇ x ⁇ 1.5)) or carbon-coated silicon oxide (carbon-coated SiO x (0 It is more preferable to use ⁇ x ⁇ 1.5)), and even more preferable to use carbon-coated silicon oxide.
  • the carbon-coated silicon oxide may be further doped with a metal element.
  • the content ratio of the carbon element in the carbon-coated silicon oxide is not particularly limited, and is preferably 0.5 to 5% by mass, more preferably 1 to 3% by mass. Commercially available silicon oxide or carbon-coated silicon oxide may be used.
  • carbon-coated silicon oxide can also be prepared by carbon-coating silicon oxide, for example, with reference to JP-A-2019-204686.
  • the content of silicon oxide or carbon-coated silicon oxide in the negative electrode active material is not particularly limited, and can be, for example, 10 to 90% by mass, preferably 10 to 50% by mass, and more preferably 15 to 40% by mass. preferable.
  • the negative electrode active material is silicon oxide or carbon-coated silicon oxide
  • the average particle size is preferably 5 to 20 ⁇ m.
  • it is also preferable to use a silicon-based material doped with a metal element as the negative electrode active material more preferably a silicon-based material doped with at least one of Li, Ni, and Ti. More preferred are doped silicon-based materials.
  • the silicon-based material to be doped with the metal element is preferably silicon oxide or carbon-coated silicon oxide.
  • silicon oxide doped with a metal element and the silicon oxide coated with both a carbon coat and a metal element doped commercially available products may be used. Further, for example, with reference to JP-A No. 2022-121582, WO 14/188851, and JP-A No. 2021-150077, doping silicon oxide or carbon-coated silicon oxide with a metal element, or It can also be prepared by doping silicon oxide with a metal element and, if necessary, further applying a carbon coat.
  • both carbon coated and doped with a metal element refers to a product that is doped with a metal element and then subjected to a carbon coat treatment, and a product that is subjected to a carbon coat treatment and then a metal element doped with a metal element. Used to include both elements doped.
  • the negative electrode active material a silicon-based material coated with both a carbon coat and doped with a metal element, and more preferably silicon oxide coated with both a carbon coat and doped with a metal element. Particularly preferred is silicon oxide which is both carbon-coated and lithium-doped.
  • the shape of the negative electrode active material is not particularly limited, but a particulate shape is preferable.
  • the average particle diameter (volume-based median diameter D50) of the negative electrode active material is preferably 0.1 to 60 ⁇ m.
  • a predetermined particle size can be prepared by a conventional method using a crusher or a classifier. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a swirling jet mill, a sieve, etc. are preferably used.
  • Wet pulverization can also be carried out in the presence of water or an organic solvent such as methanol during pulverization. In order to obtain a desired particle size, it is preferable to perform classification.
  • the classification method is not particularly limited, and a sieve, a wind classifier, etc. can be used as desired. Both dry and wet classification can be used.
  • the average particle diameter of the negative electrode active material is the value stated in the manufacturer's catalog. If information on the average particle size from the manufacturer is not available or if a synthesized negative electrode active material is used, the negative electrode active material is dispersed in water and measured using a laser diffraction/scattering particle size distribution measuring device (for example, Particle LA manufactured by HORIBA). -960V2 (trade name)), the average particle diameter value (volume-based median diameter D50 in water) is adopted.
  • the negative electrode active materials may be used alone or in combination of two or more. Among these, a combination of a silicon-based active material and a carbonaceous material is preferred, a combination of a silicon-based active material and graphite is more preferred, and a combination of silicon oxide or carbon-coated silicon oxide and graphite is even more preferred.
  • the silicon oxide and the carbon-coated silicon oxide may be silicon oxide doped with the above-mentioned metal element and silicon oxide coated with both a carbon coat and a metal element dope, respectively.
  • the metal element to be doped is preferably at least one of Li, Ni, and Ti, and more preferably one of Li, Ni, and Ti.
  • the mass ratio of the silicon-based active material to graphite is preferably 2 or less, more preferably 1 or less, and even more preferably 0.5 or less. Although there is no particular restriction on the lower limit of the mass ratio of silicon-based active material to graphite, 0.05 or more is practical.
  • the specific surface area (BET specific surface area) of the negative electrode active material is preferably 0.1 to 50 m 2 /g.
  • the specific surface area of the negative electrode active material uses the value described in the manufacturer's catalog. If specific surface area information from the manufacturer is not available or if a synthesized negative electrode active material is used, pack the negative electrode active material into a sample tube, dry it with a flow of nitrogen, and use a specific surface area/pore distribution measuring device (e.g., micro The value of the specific surface area (BET specific surface area) calculated by the BET (single point) method using the nitrogen adsorption method measured using BELSORP MINI manufactured by Track Bell Co., Ltd. is used.
  • carbon-coated silicon oxide and graphite which are used for determining the sufficiency of the above-mentioned ⁇ Storage Modulus Characteristics 1>, can be preferably used.
  • the preferred ranges of these average particle diameters and specific surface areas are as described above.
  • the content of the negative electrode active material in the electrode composition of the present invention is not particularly limited, and is preferably 10 to 99% by mass, more preferably 30 to 98% by mass, based on the total solid content. It is more preferably 45 to 97% by weight, even more preferably 55 to 95% by weight, even more preferably 65 to 95% by weight, and particularly preferably 75 to 95% by weight.
  • metal ions belonging to Group 1 or Group 2 of the periodic table generated in the secondary battery may be used instead of the negative electrode active material. Can be done. By combining these ions with electrons and depositing them as metal, a negative electrode active material layer can be formed.
  • the electrode composition of the present invention contains a conductive additive.
  • a conductive additive there are no particular limitations on the conductive aid, and those known as general conductive aids can be used.
  • electron conductive materials such as carbon black such as acetylene black, Ketjen black, and furnace black, amorphous carbon such as needle coke, carbon fibers such as vapor-grown carbon fiber or carbon nanotubes, graphene or fullerene, etc.
  • the material may be a carbonaceous material, metal powder such as copper or nickel, or metal fiber, or a conductive polymer such as polyaniline, polypyrrole, polythiophene, polyacetylene, or polyphenylene derivative.
  • Acetylene black is preferred as the conductive aid.
  • metal ions belonging to Group 1 or Group 2 of the periodic table are not inserted or released when the battery is charged and discharged, and as an active material. What is not functional is used as a conductive aid. Therefore, among conductive aids, those that can function as active materials in the active material layer when the battery is charged and discharged are classified as active materials rather than conductive aids. Whether or not it functions as an active material when charging and discharging a battery is not unique, but is determined by the combination with the active material.
  • the conductive aids may be used alone or in combination of two or more.
  • the content of the conductive aid in the electrode composition of the present invention is preferably 0.5 to 60% by mass, more preferably 1.0 to 50% by mass, and 1.5 to 50% by mass based on the total solid content. 40% by weight is more preferable, and 2.5 to 35% by weight is particularly preferable.
  • the content of the conductive aid in the electrode composition of the present invention can be 2.5 to 25% by mass, or 3.0 to 20% by mass, based on the total solid content. , 4.0 to 10% by mass.
  • the shape of the conductive aid is not particularly limited, but is preferably particulate.
  • the average particle size (volume-based median diameter D50) of the conductive additive is not particularly limited, and is, for example, preferably 0.01 to 50 ⁇ m, more preferably 0.02 to 10.0 ⁇ m, and 0.02 to 0.2 ⁇ m. is even more preferable.
  • the average particle diameter of the conductive aid is the value listed in the manufacturer's catalog. If information on the average particle size from the manufacturer is not available or when using a synthesized conductive additive, the average particle size of the conductive additive should be the average particle diameter of the negative electrode active material described above (volume-based median diameter D50 in water). ) may be used.
  • the specific surface area (BET specific surface area) of the conductive additive is preferably 10 to 100 m 2 /g.
  • the value stated in the manufacturer's catalog is used for the specific surface area of the conductive aid. If information on the specific surface area from the manufacturer is not available or when using a synthesized conductive aid, the method for measuring the specific surface area (BET specific surface area) of the negative electrode active material described above (BET method using nitrogen adsorption method) can be applied. The value given should be adopted.
  • acetylene black which is used for determining the sufficiency of the above-mentioned ⁇ Storage Modulus Characteristics 1>, can be preferably used.
  • the preferred ranges of the average particle diameter and specific surface area of acetylene black are as described above.
  • the electrode composition of the present invention may optionally contain a lithium salt, an ionic liquid, a thickener, an antifoaming agent, a leveling agent, a dehydrating agent, an antioxidant, etc. as other components other than the above-mentioned components. Can be done.
  • a lithium salt an ionic liquid, a thickener, an antifoaming agent, a leveling agent, a dehydrating agent, an antioxidant, etc.
  • the binder composition of the present invention can be prepared by mixing a water-soluble polymer (X), a water-soluble compound (Y), polymer particles, water, and optionally any other components using, for example, various commonly used mixers. By doing so, a mixture, preferably a slurry, can be prepared.
  • a mixture preferably a slurry
  • an active material and a conductive additive are mixed, and optionally, other additives are mixed to form a mixture, preferably a slurry. do.
  • the mixing method is not particularly limited, and may be mixed all at once or sequentially. Further, a mixture obtained by mixing a plurality of components may be mixed with other components.
  • components such as an active material and a conductive aid may be mixed, and some of the components of the binder composition of the present invention may be mixed.
  • the remaining components of the binder composition may be mixed. For example, after mixing a water-soluble polymer (X), a water-soluble compound (Y), an active material, a conductive agent, and water, water and polymer particles are added and further mixed to prepare the electrode composition of the present invention. You can also get
  • the electrode sheet of the present invention has a layer (electrode active material layer, that is, a negative electrode active material layer or a positive electrode active material layer) formed using the electrode composition of the present invention.
  • the electrode sheet of the present invention may be an electrode sheet having an electrode active material layer formed using the electrode composition of the present invention, and the electrode active material layer may be formed on a base material such as a current collector. It may be a sheet that does not have a base material and is formed only of an electrode active material layer (a negative electrode active material layer or a positive electrode active material layer). This electrode sheet usually has a structure in which an electrode active material layer is laminated on a current collector.
  • the electrode sheet of the present invention may have other layers such as a protective layer such as a release sheet and a coating layer.
  • the electrode sheet of the present invention is a material constituting a negative electrode active material layer or a positive electrode active material layer of a secondary battery, or a laminate of a negative electrode current collector and a negative electrode active material layer (negative electrode layer), or a positive electrode current collector and a positive electrode. It can be suitably used as a laminate of active material layers (positive electrode layer).
  • the current collector constituting the electrode sheet of the present invention is an electron carrier and is usually in the form of a film sheet.
  • the current collector can be appropriately selected depending on the active material.
  • the constituent material of the positive electrode current collector include aluminum, aluminum alloy, stainless steel, nickel, and titanium, with aluminum or aluminum alloy being preferred.
  • examples of the positive electrode current collector include those obtained by treating the surface of aluminum or stainless steel with carbon, nickel, titanium, or silver to form a coating layer (thin film).
  • the constituent material of the negative electrode current collector include aluminum, copper, copper alloy, stainless steel, nickel, and titanium, with aluminum, copper, copper alloy, or stainless steel being preferred.
  • examples of the negative electrode current collector include those obtained by treating the surface of aluminum, copper, copper alloy, or stainless steel with carbon, nickel, titanium, or silver to form a coating layer (thin film).
  • the thickness of the positive electrode active material layer constituting the electrode sheet of the present invention is not particularly limited, and can be, for example, 5 to 500 ⁇ m, preferably 20 to 200 ⁇ m. Further, the thickness of the positive electrode current collector constituting the electrode sheet of the present invention is not particularly limited, and may be, for example, 10 to 100 ⁇ m, preferably 10 to 50 ⁇ m.
  • the thickness of the negative electrode active material layer constituting the electrode sheet of the present invention is not particularly limited, and can be, for example, 5 to 500 ⁇ m, preferably 20 to 200 ⁇ m. Further, the thickness of the negative electrode current collector constituting the electrode sheet of the present invention is not particularly limited, and can be, for example, 10 to 100 ⁇ m, preferably 10 to 50 ⁇ m.
  • the electrode sheet of the present invention can be obtained by forming an electrode active material layer using the electrode composition of the present invention.
  • the electrode sheet of the present invention can be manufactured by forming a film using the electrode composition of the present invention.
  • a current collector or the like is used as a base material, and the electrode composition of the present invention is applied thereon (possibly via another layer) to form a coating film, and this is dried.
  • the secondary battery of the present invention can be obtained by incorporating the electrode sheet obtained by the above method for manufacturing an electrode sheet into at least one of the electrodes (positive electrode and negative electrode) of the secondary battery.
  • the secondary battery of the present invention In the secondary battery of the present invention, at least one of the positive electrode active material layer and the negative electrode active material layer is a layer formed using the electrode composition of the present invention.
  • the secondary battery of the present invention will be explained using the form of a non-aqueous electrolyte secondary battery as an example, but the secondary battery of the present invention is not limited to a non-aqueous electrolyte secondary battery. It broadly encompasses everything.
  • a non-aqueous electrolyte secondary battery that is a preferred embodiment of the present invention has a configuration including a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode.
  • the positive electrode has a positive electrode current collector and a positive electrode active material layer in contact with the positive electrode current collector
  • the negative electrode has a negative electrode current collector and a negative electrode active material layer in contact with the negative electrode current collector.
  • at least one of the positive electrode active material layer and the negative electrode active material layer is formed using the electrode composition of the present invention.
  • the nonaqueous electrolyte secondary battery of the present invention has only one of a positive electrode active material layer and a negative electrode active material layer, and the electrode active material layer of the nonaqueous electrolyte secondary battery of the present invention has only one of a positive electrode active material layer and a negative electrode active material layer. It also includes a non-aqueous electrolyte secondary battery formed using the electrode composition of the present invention.
  • the non-aqueous electrolyte secondary battery of the present invention functions as a secondary battery by charging and discharging by filling a non-aqueous electrolyte between the positive electrode and the negative electrode.
  • FIG. 1 is a cross-sectional view schematically showing the laminated structure of a general non-aqueous electrolyte secondary battery 10, including an operating electrode when operating the battery.
  • the nonaqueous electrolyte secondary battery 10 has a laminated structure including a negative electrode current collector 1, a negative electrode active material layer 2, a separator 3, a positive electrode active material layer 4, and a positive electrode current collector 5 in this order when viewed from the negative electrode side. are doing.
  • the space between the negative electrode active material layer and the positive electrode active material layer is filled with a non-aqueous electrolyte (not shown) and separated by a separator 3.
  • the separator 3 has pores, and functions as a positive and negative electrode separation membrane that insulates between the positive and negative electrodes while allowing electrolyte and ions to pass through the pores during normal use of the battery.
  • a positive and negative electrode separation membrane that insulates between the positive and negative electrodes while allowing electrolyte and ions to pass through the pores during normal use of the battery.
  • a light bulb is used as the operating portion 6, and the light bulb is lit by discharge.
  • the negative electrode current collector 1 and the negative electrode active material layer 2 are collectively referred to as a negative electrode
  • the positive electrode active material layer 4 and the positive electrode current collector 5 are collectively referred to as a positive electrode.
  • the secondary battery of the present invention includes an electrolytic solution (aqueous electrolyte).
  • electrolytes such as liquid, non-aqueous electrolytes
  • solid electrolyte materials such as separators.
  • these materials and members those used in ordinary secondary batteries can be used as appropriate.
  • the method for producing the secondary battery of the present invention a normal method is followed except that at least one of the positive electrode active material layer and the negative electrode active material layer is formed using the electrode composition of the present invention. It can be adopted as appropriate.
  • the members and manufacturing methods normally used for these secondary batteries for example, JP2016-201308A, JP2005-108835A, JP2012-185938A, and International Publication No. 2020/067106. etc. can be referred to as appropriate.
  • a preferred form of the non-aqueous electrolyte will be explained in more detail.
  • the electrolyte used in the nonaqueous electrolyte is preferably a salt of a metal ion belonging to Group 1 or Group 2 of the periodic table.
  • the metal ion salt used is appropriately selected depending on the intended use of the non-aqueous electrolyte. Examples include lithium salts, potassium salts, sodium salts, calcium salts, magnesium salts, etc. When used in secondary batteries etc., lithium salts are preferred from the viewpoint of output.
  • a non-aqueous electrolyte is used as an electrolyte for a lithium ion secondary battery, a lithium salt may be selected as the metal ion salt.
  • the lithium salt lithium salts commonly used in electrolytes of electrolytes for lithium ion secondary batteries are preferable, and examples thereof include the following lithium salts.
  • Inorganic lithium salt Inorganic fluoride salts such as LiPF 6 , LiBF 4 , LiAsF 6 , LiSbF 6 , perhalogenates such as LiClO 4 , LiBrO 4 , LiIO 4 , inorganic chloride salts such as LiAlCl 4 etc
  • Oxalatoborate salt lithium bis(oxalato)borate, lithium difluorooxalatoborate, etc.
  • LiPF 6 , LiBF 4 , LiAsF 6 , LiSbF 6 , LiClO 4 , Li(R f1 SO 3 ), LiN(R f1 SO 2 ) 2 , LiN(FSO 2 ) 2 , or LiN(R f1 SO 2 ) (R f2 SO 2 ) is preferred, and LiPF 6 , LiBF 4 , LiN(R f1 SO 2 ) 2 , LiN(FSO 2 ) 2 or LiN(R f1 SO 2 )(R f2 SO 2 ) is more preferred.
  • R f1 and R f2 each represent a perfluoroalkyl group, and preferably have 1 to 6 carbon atoms. Note that the electrolytes used in the non-aqueous electrolyte may be used alone or in any combination of two or more.
  • the salt concentration of the electrolyte (preferably ions of metals belonging to Group 1 or Group 2 of the periodic table or metal salts thereof) in the non-aqueous electrolyte is selected as appropriate depending on the purpose of use of the non-aqueous electrolyte, but generally is 10 to 50% by mass, preferably 15 to 30% by mass, based on the total mass of the nonaqueous electrolyte.
  • the molar concentration is preferably 0.5 to 1.5M. Note that when evaluating the concentration of ions, it may be calculated in terms of metal salts that are suitably applied.
  • Non-aqueous solvent The non-aqueous electrolyte contains a non-aqueous solvent.
  • aprotic organic solvents are preferred, and aprotic organic solvents having 2 to 10 carbon atoms are particularly preferred.
  • Such nonaqueous solvents include chain or cyclic carbonate compounds, lactone compounds, chain or cyclic ether compounds, ester compounds, nitrile compounds, amide compounds, oxazolidinone compounds, nitro compounds, chain or cyclic sulfones, or Examples include sulfoxide compounds and phosphate ester compounds. Note that compounds having an ether bond, a carbonyl bond, an ester bond, or a carbonate bond are preferred. These compounds may have a substituent, and examples of the substituent that may be included include substituents selected from the above-mentioned substituent group T.
  • nonaqueous solvent examples include ethylene carbonate, fluorinated ethylene carbonate, vinylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, methylpropyl carbonate, ⁇ -butyrolactone, ⁇ -valerolactone, 1, 2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,3-dioxane, 1,4-dioxane, methyl acetate, ethyl acetate, propion Methyl acid, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethyl acetate, ethyl trimethyl acetate, acetonitrile, glutaronitrile, adiponitrile, me
  • ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, and ⁇ -butyrolactone is preferable, and high viscosity (high dielectric constant) solvents such as ethylene carbonate or propylene carbonate (for example, A combination of a dielectric constant ⁇ 30) and a low viscosity solvent (for example, viscosity ⁇ 1 mPa ⁇ s) such as dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate is more preferable.
  • high viscosity solvents such as ethylene carbonate or propylene carbonate
  • a low viscosity solvent for example, viscosity ⁇ 1 mPa ⁇ s
  • the dissociation property of the electrolyte salt and the mobility of ions are improved.
  • the nonaqueous solvent used in the present invention is not limited to these.
  • the secondary battery of the present invention can be used, for example, in a notebook computer, a pen input computer, a mobile computer, an e-book player, a mobile phone, a cordless phone, a pager, a handy terminal, a mobile fax machine, a mobile copier, a mobile printer, a headphone stereo, a video It can be installed in electronic devices such as movies, LCD TVs, handy cleaners, portable CDs, mini discs, electric shavers, transceivers, electronic notebooks, calculators, portable tape recorders, radios, backup power sources, and memory cards.
  • electronic devices such as movies, LCD TVs, handy cleaners, portable CDs, mini discs, electric shavers, transceivers, electronic notebooks, calculators, portable tape recorders, radios, backup power sources, and memory cards.
  • Solution I was prepared by stirring and mixing. 337.5 g of distilled water was added to a 1 L three-neck flask equipped with a reflux condenser and a gas introduction cock.
  • Water-soluble polymer (X) used for preparing binder composition 5 Water-soluble polymer (X) used for preparing binder composition 5)
  • PAAm water-soluble polymer
  • acrylamide, N-(2-hydroxyethyl)acrylamide and tert-butylacrylamide were used instead of acrylamide
  • - Butylacrylamide 85:10:5 (mass ratio) was used in the preparation of binder composition 5 described in Table 1 in the same manner as the synthesis of water-soluble polymer (X) (PAAm).
  • An aqueous solution of water-soluble polymer (X) (PAAm-HEAA-TBAAm) to be used was obtained.
  • the solid content concentration was 11.3% by mass, and the weight average molecular weight was 724,269.
  • Water-soluble polymer (X) used for preparing binder composition 6 (Water-soluble polymer (X) used for preparing binder composition 6)
  • PAAm water-soluble polymer
  • PAAm-AN aqueous solution of water-soluble polymer (X) used in the preparation of binder composition 6 shown in Table 1 below was obtained.
  • the solid content concentration was 13.3% by mass, and the weight average molecular weight was 189,373.
  • CLPA-C07 (trade name, crosslinked copolymer binder consisting of acrylic acid and a hydrophobic monomer, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. ) was used. The solid content concentration was adjusted to 10.0% by mass.
  • CLPA-C07 is a polymer that does not have a constituent represented by general formula (B-2).
  • CLPA-W11 (trade name, cross-linked polyacrylic acid binder, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was used as an aqueous solution of a water-soluble polymer used in the preparation of binder composition c7 listed in Table 1 below. The solid content concentration was adjusted to 10.3% by mass.
  • CLPA-W11 is a polymer that does not have a constituent represented by general formula (B-2). For convenience, these water-soluble polymers (CLPA-C07 and CLPA-W11) are shown in the "Water-soluble polymer (X)" column of Table 1 below.
  • Binder Composition 1 shown in Table 1 below was prepared as follows. Specifically, 1.45 g (solid content 0.20 g) of the aqueous solution of the water-soluble polymer (X) (PAAm) obtained above was added with 1.5 g of an aqueous solution of carboxymethyl cellulose (CMC) as the water-soluble compound (Y). 68 g (solid content 0.08 g), polymer particles 1 as polymer particles (Z) (synthesized according to the production example of copolymer latex 1 described in paragraph number 0038 of JP-A-2012-212537) 0.
  • Binder Composition 1 was obtained by adding 41 g (solid content: 0.20 g) and dispersing for 21 minutes at 2000 rpm using Awatori Rentaro (trade name, manufactured by THINKY). The solid content concentration of Binder Composition 1 was 14% by mass.
  • binder compositions 2-6 and c1-c9 In preparing binder composition 1, binder compositions 2 to 6 and c1 to c9 were prepared in the same manner as binder composition 1, except that the components and content ratios (mass ratios) listed in Table 1 below were adopted. Prepared. Although the water glass used in binder composition c9 is not a polymer particle, it is shown in the "Polymer particle (Z)" column in Table 1 below for convenience.
  • the mass ratio of the contents of the above three components is determined as "(X) (Y)” in Table 1 below. (Z) mass ratio” column. The mass ratio was calculated from the solid content of each component.
  • Electrode compositions E1 to E6 and cE1 to cE9 Electrode compositions containing the components of each of the binder compositions described above and carbon-coated silicon oxide as a high-capacity active material were prepared. Each of the obtained electrode compositions contained specific amounts of carbon-coated silicon oxide, graphite, and acetylene black with a specific average particle size and specific surface area, and was tested for ⁇ storage modulus property 1>. This corresponds to the slurry used.
  • electrode compositions E1 to E6 and cE1 to cE9 are electrode compositions containing the components of binder compositions 1 to 6 and c1 to c9, respectively.
  • Electrode composition E1 In a 60 mL ointment container (manufactured by Umano Chemical Co., Ltd.), SiOC (carbon-coated silicon oxide (carbon element content ratio 1.3% by mass)) as an active material, manufactured by Osaka Titanium Technologies, grade: SiO NC 5 ⁇ m, Average particle size: 5 ⁇ m, specific surface area: 2.6 m 2 /g) 1.78 g and graphite (trade name: MAG-D, manufactured by Showa Denko Materials Co., Ltd., average particle size: 21 ⁇ m, specific surface area: 4 m 2 /g) 7.12 g, 0.60 g of acetylene black (trade name: Denka Black, manufactured by Denka Co., Ltd., powder product, average particle size: 35 nm, specific surface area: 68 m 2 /g) as a conductive aid, the water-soluble material obtained above Add 1.45 g (solid content 0.20 g) of an aqueous solution of polymer (X), 1.68
  • This electrode composition E1 contains 100 parts by mass of total solids, 17.8 parts by mass of carbon-coated silicon oxide, 71.2 parts by mass of graphite, 6 parts by mass of acetylene black, and a binder component (water-soluble The slurry contained 5 parts by mass of solids (polymer (X), water-soluble compound (Y), and polymer particles (Z)), and the total solid content in the slurry was 52% by mass. Note that in the electrode composition E1, the water-soluble polymer (X), the water-soluble compound (Y), the polymer molecule, distilled water, etc. are separately added, but the active material is added to the binder composition 1.
  • the binder components water-soluble polymer (X), water-soluble compound (Y), and polymer particles (Z) contained in electrode composition E1 have the same type and mass ratio as the binder component in binder composition 1 above. are similar.
  • Electrode compositions E2 to E6 and cE1 to cE9 were prepared in the same manner as in the preparation of electrode composition E1, except for the following changes.
  • Electrode compositions E7 to E12 and cE10 to cE16 Each electrode composition containing the components of each of the binder compositions described above and containing silicon oxide coated with both carbon and doped with lithium as a high-capacity active material was prepared as follows. In addition, since each of the obtained electrode compositions uses silicon oxide coated with both a carbon coat and a metal element dope (lithium dope), the slurry used for determining ⁇ storage modulus characteristic 1> It is not equivalent.
  • Silicon oxide coated with both carbon coat and lithium dope in the same manner as the method described in Example 1-1 of JP-A-2022-121582 was created. Specifically, it was performed as follows. (i) Preparation of carbon-coated silicon oxide A raw material (vaporization starting material) containing metallic silicon and silicon dioxide is placed in a reaction furnace, vaporized in a vacuum atmosphere of 10 Pa, and deposited on an adsorption plate. After cooling sufficiently, the deposit (silicon oxide) was taken out and ground in a ball mill. After adjusting the particle size, a carbon coat was formed by thermal CVD (thermal chemical vapor deposition).
  • thermal CVD thermal chemical vapor deposition
  • pulverized silicon oxide was placed in a silicon nitride tray, and then placed in a processing furnace capable of maintaining an atmosphere.
  • argon gas was introduced to replace the inside of the processing furnace with argon, and then the temperature was raised at a rate of 300°C/hr while a methane-argon mixed gas was introduced at a rate of 2NL/min until the temperature reached 600 to 1,100°C.
  • thermal CVD was performed by holding the sample for 3 to 10 hours to obtain carbon-coated silicon oxide (SiOC). After the holding was completed, the temperature was started to decrease, and after reaching room temperature, the powder was collected.
  • the temperature of solution A when immersing the carbon-coated silicon oxide was 20° C., and the immersion time was 20 hours. Thereafter, the solid content was collected by filtration.
  • the carbon-coated silicon oxide was doped with lithium.
  • the obtained solid content was heat treated at 600° C. for 24 hours in an argon atmosphere to stabilize the Li compound. In this way, the carbon-coated silicon oxide was modified to obtain silicon oxide (LiSiOC) that was both carbon-coated and lithium-doped.
  • the content ratio of carbon element was 3% by mass, and the average particle size (volume-based median diameter D50) of the LiSiOC particles was 6.7 ⁇ m.
  • Electrode Composition E1 the carbon-coated silicon oxide was changed to the carbon-coated and lithium-doped silicon oxide (LiSiOC), and the binder component (water-soluble Electrode composition E1 except that the compositions of polymer (X), water-soluble compound (Y) and polymer particles (Z) were changed to be the same as the binder composition listed in Table 1 below.
  • Electrode compositions E7 to E12 and cE10 to cE16 were prepared in the same manner as in the preparation. The corresponding binder compositions are shown in the "Corresponding Binder Composition No.” column of Table 2 below.
  • Electrode compositions E13 to E24 and cE17 to cE30 For each electrode containing the components of each of the above binder compositions and containing silicon oxide coated with both carbon coating and nickel doping, or silicon oxide coated with both carbon coating and titanium doping as a high capacity active material. A composition was prepared as follows. In addition, since each of the obtained electrode compositions uses silicon oxide coated with both a carbon coat and a metal element dope (nickel dope or titanium dope), the determination of ⁇ storage modulus characteristic 1> is difficult. It is not equivalent to the slurry used for.
  • the atmosphere during the preparation of the molten alloy and during gas atomization was an argon atmosphere. Furthermore, during gas atomization, high-pressure (4 MPa) argon gas was sprayed onto the molten alloy falling in a rod shape inside the spray chamber. The obtained powder was classified to 25 ⁇ m or less using a sieve and used as a Si alloy in subsequent steps.
  • (ii) Preparation for mechanical milling process Place a metal ball (size: 3/8 inch in diameter, material: SUJ2 (high carbon chromium bearing steel SUJ2 according to JIS (Japanese Industrial Standards) G 4805 (2019)) in a stainless steel pot. ), Si alloy and SiO 2 powder as a metal oxide were added at a mixing ratio shown in Table A below.
  • Carbon coating treatment on a silicon-based material doped with a metal element A carbon coat was formed on a silicon-based material (NiSiO or TiSiO) doped with a metal element by performing thermal CVD.
  • the silicon-based material doped with a metal element after mechanical milling was placed in a silicon nitride tray, and then placed in a processing furnace capable of maintaining an atmosphere.
  • argon gas was introduced to replace the inside of the processing furnace with argon, and then the temperature was raised at a rate of 300°C/hr while a methane-argon mixed gas was introduced at a rate of 2NL/min until the temperature reached 600 to 1,100°C.
  • the carbon film is then thermally CVDed by holding it for 3 to 10 hours to form a silicon-based material coated with carbon and doped with a metal element (silicon oxide coated with both carbon coat and nickel doped (NiSiOC)). ) and both carbon-coated and titanium-doped silicon oxide (TiSiOC)) were obtained. After the holding was completed, the temperature started to decrease, and after reaching room temperature, the powder was collected. Note that the content ratio of carbon element was 3% by mass, and the average particle diameter (volume-based median diameter D50) of both NiSiOC particles and TiSiOC particles was 7 ⁇ m.
  • NiSiO Nickel-doped silicon oxide
  • TiSiO Titanium-doped silicon oxide alloy
  • Composition Total of 100% by mass of Si alloy and SiO 2 powder input when obtaining a silicon-based material (NiSiO or TiSiO) doped with a metal element It shows the proportion of each metal element in the Si alloy, the unit is mass %, and the total alloy composition is 95 mass %.
  • Mixing ratio Indicates the ratio of each component (Si alloy or SiO 2 powder) to the total amount of Si alloy and SiO 2 powder added when obtaining a silicon-based material (NiSiO or TiSiO) doped with a metal element, and the unit is Mass%.
  • electrode composition E1 the carbon-coated silicon oxide was changed to the carbon-coated and nickel-doped silicon oxide (NiSiOC), and the binder component (water-soluble Electrode composition E1 except that the compositions of polymer (X), water-soluble compound (Y), and polymer particles (Z) were changed to be the same as each binder composition listed in Table 1 below.
  • Electrode compositions E13 to E18 and cE17 to cE23 were prepared in the same manner as in the preparation. The corresponding binder compositions are shown in the "Corresponding Binder Composition No.” column in Table 3 below.
  • electrode composition E1 the carbon-coated silicon oxide was changed to silicon oxide (TiSiOC) that was both carbon-coated and titanium-doped, and the binder component (water-soluble polymer (X ), water-soluble compound (Y) and polymer particles (Z)) were changed to be the same as each binder composition listed in Table 1 below. Accordingly, electrode compositions E19 to E24 and cE24 to cE30 were prepared. The corresponding binder compositions are shown in the "Corresponding Binder Composition No.” column in Table 3 below.
  • Adhesive tape (width: 10 mm, height: 50 mm, product name: Nystack Business Pack, manufactured by Nichiban Co., Ltd.) was pasted on the negative electrode active material layer of each of the three test pieces that were cut out, and pulled at a rate of 100 mm/min at a 90° angle. The average stress upon peeling was measured for each test piece. For the measurement, a small desktop tester (FGS-TV (trade name), manufactured by Nidec-Shimpo Corporation) was used. The value (unit: N/m) obtained by dividing the sum of the obtained average stresses by 3 is shown in the "peel strength" column of Tables 2 and 3 below.
  • Nonaqueous electrolyte secondary battery 101 A non-aqueous electrolyte secondary battery 101 was produced.
  • Each electrode composition prepared above was applied onto a 20 ⁇ m thick copper foil (current collector) using an applicator and dried at 90° C. for 1 hour. Thereafter, it was pressurized using a press and then dried at 100° C. in vacuum for 10 hours to obtain a negative electrode sheet (negative electrode active material layer + copper foil) with a negative electrode active material layer having a thickness of 25 ⁇ m.
  • a disk with a diameter of 13.0 mm was cut out from the negative electrode sheet to obtain a disk-shaped negative electrode sheet.
  • Lithium foil (thickness 50 ⁇ m, 14.5 mm ⁇ ) and polypropylene separator (thickness 25 ⁇ m, 16.0 mm ⁇ ) are stacked in this order, and 200 ⁇ L of LiPF 6 ethylene carbonate/ethyl methyl carbonate (volume ratio 1:2) electrolyte (concentration 1M) is added. It soaked into the separator. 200 ⁇ L of the above electrolyte solution was further soaked onto the separator, and a disk-shaped negative electrode sheet was stacked so that the negative electrode active material layer surface was in contact with the separator. Thereafter, the 2032 type coin case was caulked to produce a nonaqueous electrolyte secondary battery 101 (a battery having a laminate consisting of Li foil, separator, negative electrode active material layer, and copper foil).
  • a nonaqueous electrolyte secondary battery 101 a battery having a laminate consisting of Li foil, separator, negative electrode active material layer, and copper foil.
  • Non-aqueous electrolyte secondary batteries 102 to 124 and c101 to c130 In producing the non-aqueous electrolyte secondary battery 101, the non-aqueous electrolyte Secondary batteries 102 to 124 and c101 to c130 were prepared.
  • the cycle characteristics were evaluated by repeating 80 cycles of charging and discharging, with one charging and one discharging being defined as one charging/discharging cycle.
  • discharge capacity at the first cycle after initialization initial discharge capacity
  • discharge capacity retention rate after 80 cycles of charging and discharging 100 x "Discharge capacity after 80 cycles of charging and discharging” / "Initial discharge capacity”
  • results are listed in the "Capacity Retention Rate 80 cyc" column in Tables 2 and 3 below. Note that both charging and discharging were performed at 25°C.
  • PAAm Polyacrylamide
  • CLPA-C07 trade name, crosslinked copolymer binder consisting of acrylic acid and hydrophobic monomer, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.
  • CLPA-W11 trade name, crosslinked polyacrylic acid binder, Fujifilm Wa CMC manufactured by Hikari Pure Chemical Industries: Carboxymethylcellulose (degree of etherification 0.66, trade name: Celogen WS-C, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
  • Selenpia trade name, cellulose nanofiber, manufactured by Nippon Paper Industries Co., Ltd.
  • Polymer particles 1 Synthesized according to the preparation example of copolymer latex 1 described in paragraph number 0038 of JP-A-2012-212537.
  • Polymer particles 2 Synthesized according to the synthesis example of copolymer latex (B-2) described in paragraph number 0044 of JP-A-2011-171181.
  • Binder composition No. corresponding to the combination of binder components (water-soluble polymer (X), water-soluble compound (Y), and polymer particles (Z)) blended into the electrode composition.
  • SiOC carbon-coated silicon oxide (manufactured by Osaka Titanium Technologies, grade: SiO NC 5 ⁇ m, average particle size: 5 ⁇ m, specific surface area: 2.6 m 2 /g, carbon element content ratio 1.3% by mass)
  • LiSiOC Silicon oxide prepared above with both the carbon coat and lithium doping (average particle size: 6.7 ⁇ m, carbon element content ratio 3% by mass)
  • Graphite MAG-D (trade name, manufactured by Showa Denko Materials Co., Ltd., average particle size: 21 ⁇ m, specific surface area: 4 m 2 /g)
  • AB Acetylene black (trade name: Denka Black, manufactured by Denka Corporation, powdered product, average particle size: 35 nm, specific surface area: 68 m 2 /g)
  • Content Indicates the proportion of each component (solid content) in the total of each component (solid content) contained in the electrode composition, and the unit is mass %.
  • G C ' Storage modulus at 0.01% shear
  • Binder composition No. corresponding to the combination of binder components (water-soluble polymer (X), water-soluble compound (Y), and polymer particles (Z)) blended into the electrode composition.
  • NiSiOC Silicon oxide prepared above with both carbon coat and nickel doping (average particle size: 7 ⁇ m, carbon element content ratio 3% by mass)
  • TiSiOC Silicon oxide prepared above with both the carbon coat and titanium doping (average particle size: 7 ⁇ m, carbon element content ratio 3% by mass)
  • Graphite MAG-D (trade name, manufactured by Showa Denko Materials Co., Ltd., average particle size: 21 ⁇ m, specific surface area: 4 m 2 /g)
  • AB Acetylene black (trade name: Denka Black, manufactured by Denka Corporation, powdered product, average particle size: 35 nm, specific surface area: 68 m 2 /g)
  • Content Indicates the proportion of each component (solid content) in the total of each component (solid content) contained in the electrode composition, and the unit is mass %.
  • G C ' Storage modulus at 0.01% shear strain
  • G D ' Storage modulus at 10% shear strain
  • Binder compositions c1 to c9 contain a water-soluble polymer (X) containing a component represented by general formula (B-2), a water-soluble compound (Y), polymer particles, and water;
  • the tensile modulus is 1500 to 9800 MPa, and the difference between the storage modulus G A ' at a shear strain of 0.01% and the storage modulus G B ' at a shear strain of 10% (G A '-G B ') is 100
  • This is a binder composition that does not satisfy at least one of the following conditions: Binder compositions c1 to c9 were coated with both carbon and doped with a metal element even when used in electrode compositions cE1 to cE9 that employed carbon-coated silicon oxide as a high-capacity active material.
  • Binder compositions 1 to 6 contain a water-soluble polymer (X) containing a component represented by general formula (B-2), a water-soluble compound (Y), polymer particles, and water, and The difference between the storage elastic modulus G A ' at a shear strain of 0.01% and the storage elastic modulus G B ' at a shear strain of 10% of the binder composition when the elastic modulus is 1500 to 9800 MPa (G A '-G B ') is 100 to 1000 Pa (satisfying ⁇ storage modulus property 1>). Binder compositions 1 to 6 were coated with both carbon and doped with a metal element even when used in electrode compositions E1 to E6, which employed carbon-coated silicon oxide as a high-capacity active material.
  • the electrode composition of the present invention suppresses destruction of the conductive network structure because it has excellent cycle characteristics. It can be seen that the electrode composition of the present invention can sufficiently improve the adhesion of the obtained negative electrode sheet and improve the cycle characteristics of the obtained secondary battery. It can be seen that the binder composition of the present invention can be used to obtain the electrode composition of the present invention. Furthermore, it can be seen that the electrode sheet and secondary battery using the electrode composition of the present invention have high adhesion and excellent cycle characteristics.
  • Nonaqueous electrolyte secondary battery 1 Negative electrode current collector 2 Negative electrode active material layer 3 Separator 4 Positive electrode active material layer 5 Positive electrode current collector 6 Operating part (light bulb)

Abstract

A binder composition for a secondary battery, said binder composition including water-soluble macromolecules (X), a water-soluble compound (Y), and polymer particles, wherein the water-soluble macromolecules (X) are a polymer that includes a constituent component having a prescribed structure, and the binder composition satisfies properties in which the tensile elastic modulus of the binder composition is 1500-9800 MPa, and as measured according to specific parameters, the difference in the storage elastic modulus at shear strains of 0.01% and 10% is 100-1000 Pa. Additionally, an electrode sheet, a secondary battery, a manufacturing method for said electrode sheet, and a manufacturing method for said secondary battery.

Description

二次電池用バインダー組成物、電極用組成物、電極シート及び二次電池、並びに、これら電極シート及び二次電池の製造方法Binder composition for secondary batteries, composition for electrodes, electrode sheets and secondary batteries, and methods for producing these electrode sheets and secondary batteries
　本発明は、二次電池用バインダー組成物、電極用組成物、電極シート及び二次電池、並びに、これら電極シート及び二次電池の製造方法に関する。 The present invention relates to a binder composition for secondary batteries, a composition for electrodes, an electrode sheet, and a secondary battery, and a method for manufacturing these electrode sheets and secondary batteries.
　リチウムイオン二次電池に代表される二次電池は、パソコン、ビデオカメラ、携帯電話等のポータブル電子機器の動力源として用いられている。最近では、二酸化炭素排出量削減という地球規模の環境課題を背景に、自動車等の輸送機器の動力電源として、また、夜間電力、自然エネルギー発電による電力等の蓄電用途としても普及してきている。 Secondary batteries, typified by lithium ion secondary batteries, are used as a power source for portable electronic devices such as personal computers, video cameras, and mobile phones. Recently, against the backdrop of the global environmental challenge of reducing carbon dioxide emissions, they have become popular as a power source for transportation equipment such as automobiles, and as a storage device for nighttime electricity, electricity generated from natural energy, etc.
　リチウムイオン二次電池の電極（正極及び負極）は一般的には電極活物質層（正極活物質層及び負極活物質層）を有し、この電極活物質層は、充放電時にリチウムイオンを吸蔵ないし放出可能な電極活物質粒子を含み、また、必要により導電助剤等を含む。電極活物質、導電助剤等はいわゆる固体粒子であり、リチウムイオン二次電池の充放電（リチウムイオンの吸蔵放出）に伴う電極活物質粒子の膨張収縮により、固体粒子間の導通状態は損なわれやすい。導通状態が損なわれれば電池の内部抵抗が増大して電池容量が低下する。リチウムイオン二次電池のサイクル特性を向上させる（サイクル寿命を長期化する）には、充放電を繰り返しても固体粒子間の密着状態を維持できることが重要であり、電極活物質層は通常、バインダーを含む。
　例えば、特許文献１には、粒子状重合体及び水溶性重合体を含むリチウムイオン二次電池電極用バインダー組成物が記載されている。特許文献１には、この組成物を構成する水溶性重合体が、エチレン性不飽和カルボン酸単量体単位と、（メタ）アクリルアミド、Ｎ－２－ジメチルアミノエチル（メタ）アクリルアミド、Ｎ－３－ジメチルアミノプロピル（メタ）アクリルアミドから選ばれる一種以上のカルボン酸アミド単量体単位と、上記カルボン酸アミド単量体単位以外の架橋性単量体単位とを、それぞれ特定の割合で含むこと；この組成物と、電極活物質と、カルボキシメチルセルロース塩とを組み合わせて、リチウムイオン二次電池の電極形成に適用することによって、得られるリチウムイオン二次電池中においてガスの発生を抑制し、リチウムイオン二次電池のサイクル特性が向上することが記載されている。 The electrodes (positive electrode and negative electrode) of a lithium ion secondary battery generally have an electrode active material layer (positive electrode active material layer and negative electrode active material layer), and this electrode active material layer occludes lithium ions during charging and discharging. The electrode active material particles may include releasable electrode active material particles, and may also contain a conductive additive, etc., if necessary. Electrode active materials, conductive aids, etc. are so-called solid particles, and due to expansion and contraction of electrode active material particles associated with charging and discharging (intercalation and release of lithium ions) of a lithium ion secondary battery, the conductivity between solid particles is impaired. Cheap. If the conduction state is impaired, the internal resistance of the battery increases and the battery capacity decreases. In order to improve the cycle characteristics of lithium-ion secondary batteries (lengthen the cycle life), it is important to be able to maintain the adhesion state between solid particles even after repeated charging and discharging, and the electrode active material layer is usually made of a binder. including.
For example, Patent Document 1 describes a binder composition for a lithium ion secondary battery electrode that includes a particulate polymer and a water-soluble polymer. Patent Document 1 discloses that the water-soluble polymer constituting this composition contains an ethylenically unsaturated carboxylic acid monomer unit, (meth)acrylamide, N-2-dimethylaminoethyl (meth)acrylamide, N-3 - Containing one or more carboxylic acid amide monomer units selected from dimethylaminopropyl (meth)acrylamide and crosslinkable monomer units other than the above-mentioned carboxylic acid amide monomer units in specific proportions; By combining this composition, an electrode active material, and a carboxymethylcellulose salt and applying it to the electrode formation of a lithium ion secondary battery, gas generation is suppressed in the resulting lithium ion secondary battery, and lithium ion It is described that the cycle characteristics of secondary batteries are improved.
特許第６３６１６５５号Patent No. 6361655
　近年、二次電池の用途の拡大に伴い、二次電池には高エネルギー密度化及びサイクル特性の更なる向上が求められている。リチウムイオン二次電池の更なる高容量化を実現するために、負極活物質としてケイ素系活物質を用いる検討が盛んに行われている。負極にケイ素系活物質を用いると高エネルギー密度化が可能となる。しかし、ケイ素系活物質は充電時にリチウムイオンを多量に吸蔵して大きく膨張するため、その分、放電時におけるケイ素系活物質の収縮幅も大きくなる。したがって、負極活物質としてケイ素系活物質を用いたリチウムイオン二次電池は、充放電時の負極活物質の体積変化が大きく、固体粒子（電極活物質、導電助剤等）間の導通状態（密着状態）が損なわれやすい。充放電の繰り返しにより導通状態が損なわれると、電池の内部抵抗が増大して電池性能が低下しやすい。つまり、サイクル特性の向上には制約がある。
　本発明者らは、かかるケイ素系活物質を負極活物質として用いた二次電池において、上記特許文献１に記載されたバインダーなどの従来の電極用バインダーがサイクル特性に与える影響について検討した。その結果、従来の電極用バインダーでは、充放電に伴うケイ素系活物質のダイナミックな体積変化に十分に対応することができず、電極シートの密着性及び二次電池のサイクル特性を両立して目的の高いレベルへと導くことが難しいことが明らかとなってきた。 In recent years, as the uses of secondary batteries have expanded, secondary batteries are required to have higher energy density and further improved cycle characteristics. In order to further increase the capacity of lithium ion secondary batteries, studies are actively underway to use silicon-based active materials as negative electrode active materials. When a silicon-based active material is used for the negative electrode, it becomes possible to increase the energy density. However, since the silicon-based active material absorbs a large amount of lithium ions and expands greatly during charging, the width of contraction of the silicon-based active material during discharging increases accordingly. Therefore, in a lithium ion secondary battery using a silicon-based active material as the negative electrode active material, the volume of the negative electrode active material changes greatly during charging and discharging, and the conduction state between solid particles (electrode active material, conductive agent, etc.) adhesion) is likely to be impaired. If the conduction state is impaired due to repeated charging and discharging, the internal resistance of the battery increases and battery performance tends to deteriorate. In other words, there are restrictions on improving cycle characteristics.
The present inventors investigated the influence of conventional electrode binders, such as the binder described in Patent Document 1, on cycle characteristics in a secondary battery using such a silicon-based active material as a negative electrode active material. As a result, conventional binders for electrodes are unable to adequately respond to the dynamic volume changes of silicon-based active materials that occur during charging and discharging. It has become clear that it is difficult to lead students to a high level.
　本発明は、充放電時の体積変化の大きな電極活物質を用いた場合でも、得られる電極シートの密着性（負極活物質層－集電体間の密着性）を十分に高め、かつ、得られる二次電池のサイクル特性を十分に高める（サイクル寿命を十分に長期化する）ことができる二次電池用バインダー組成物及び電極用組成物を提供することを課題とする。
　更に、本発明は、上記二次電池用バインダー組成物又は電極用組成物を用いた電極シート及び二次電池を提供することを課題とする。更に、本発明は、上記電極シート及び二次電池の製造方法を提供することを課題とする。 The present invention is capable of sufficiently increasing the adhesion of the resulting electrode sheet (adhesion between the negative electrode active material layer and the current collector) even when using an electrode active material that exhibits large volume changes during charging and discharging. An object of the present invention is to provide a binder composition for a secondary battery and a composition for an electrode that can sufficiently improve the cycle characteristics (sufficiently extend the cycle life) of a secondary battery.
Furthermore, an object of the present invention is to provide an electrode sheet and a secondary battery using the binder composition for a secondary battery or the composition for an electrode. Furthermore, it is an object of the present invention to provide a method for manufacturing the above-mentioned electrode sheet and secondary battery.
　本発明者らは上記課題に鑑み、バインダーを構成するポリマーの化学構造、バインダーの物性ないし形状について種々の検討を重ねた。その結果、特定の構造を有する水溶性高分子（Ｘ）と、水溶性化合物（Ｙ）と、重合体粒子と、水とを組み合わせてなるバインダー組成物であって、特定の引張弾性率を示し、かつ、電極活物質及び導電助剤を共存させた電極用組成物とした場合に、せん断ひずみの程度と貯蔵弾性率との関係が特定の関係になるように制御したバインダー組成物が、二次電池の層内又は層間の優れた結着性に効果的に寄与して、電極シートの密着性を高め、かつ、二次電池のサイクル寿命を十分に長期化できることを見出した。本発明はこれらの知見に基づき更に検討を重ね、完成されるに至ったものである。 In view of the above problems, the present inventors have conducted various studies on the chemical structure of the polymer constituting the binder, and the physical properties and shape of the binder. As a result, a binder composition consisting of a combination of a water-soluble polymer (X) having a specific structure, a water-soluble compound (Y), polymer particles, and water, which exhibits a specific tensile modulus, was obtained. , and when an electrode composition is prepared in which an electrode active material and a conductive additive coexist, the binder composition is controlled so that the relationship between the degree of shear strain and the storage modulus is a specific relationship. It has been found that the present invention can effectively contribute to excellent adhesion within or between layers of a secondary battery, enhance the adhesion of the electrode sheet, and sufficiently extend the cycle life of the secondary battery. The present invention was completed after further studies based on these findings.
　すなわち、本発明の上記課題は以下の手段により解決された。
＜１＞
　水溶性高分子（Ｘ）、水溶性化合物（Ｙ）、重合体粒子及び水を含む二次電池用バインダー組成物であって、
　上記水溶性高分子（Ｘ）は、下記一般式（Ｂ－２）で表される構成成分を含む重合体であり、
　上記バインダー組成物の引張弾性率が１５００～９８００ＭＰａであり、且つ、
　下記＜貯蔵弾性率特性１＞を満たす、二次電池用バインダー組成物。
＜貯蔵弾性率特性１＞
　平均粒径が１～１０μｍかつ比表面積１～１０ｍ２／ｇの粉末状であるカーボンコートされた酸化ケイ素と、平均粒径が１５～２５μｍかつ比表面積１～１０ｍ２／ｇの粉末状である黒鉛と、平均粒径が３０～４０ｎｍかつ比表面積６５～７５ｍ２／ｇの粉末状であるアセチレンブラックと、上記二次電池用バインダー組成物とを下記量比となるよう調製したスラリーにおいて、該スラリーのせん断ひずみ０．０１％における貯蔵弾性率ＧＡ’とせん断ひずみ１０％における貯蔵弾性率ＧＢ’との差が１００～１０００Ｐａとなる特性。
－量比－
　スラリー中の全固形分１００質量部に対して、上記カーボンコートされた酸化ケイ素の含有量を１７．８質量部、上記黒鉛の含有量を７１．２質量部、上記アセチレンブラックの含有量を６質量部、上記二次電池用バインダー組成物中の固形分の含有量を５質量部とし、かつスラリー中の全固形分量を５２質量％とする。
Figure JPOXMLDOC01-appb-I000002
　一般式（Ｂ－２）中、Ｒ２１～Ｒ２３は水素原子、シアノ基又は炭素数１～６のアルキル基を示し、Ｒ２４は水素原子、アシル基、ヒドロキシ基、フェニル基又はカルボキシ基を示し、Ｌ２１は単結合、炭素数１～１６のアルキレン基、炭素数６～１２のアリーレン基、酸素原子、硫黄原子、カルボニル基若しくはイミノ基、又はこれらを組み合わせた連結基を示す。＊は上記水溶性高分子（Ｘ）の主鎖中に組み込まれるための結合部位を示す。
＜２＞
　上記水溶性高分子（Ｘ）中、上記一般式（Ｂ－２）で表される構成成分の含有量が８０質量％以上である、＜１＞に記載の二次電池用バインダー組成物。
＜３＞
　上記一般式（Ｂ－２）で表される構成成分が（メタ）アクリルアミド成分を含む、＜１＞又は＜２＞に記載の二次電池用バインダー組成物。
＜４＞
　上記水溶性高分子（Ｘ）が、アクリロニトリル成分、Ｎ－ビニル－２－ピロリドン成分及びスチレン成分の少なくとも１種を、更に含む重合体である、＜１＞～＜３＞のいずれか１項に記載の二次電池用バインダー組成物。
＜５＞
　上記水溶性化合物（Ｙ）が多糖類を含む、＜１＞～＜４＞のいずれか１項に記載の二次電池用バインダー組成物。
＜６＞
　上記水溶性化合物（Ｙ）が、カルボキシメチルセルロース、セルロースナノファイバー、ヒドロキシエチルセルロース、ヒドロキシプロピルセルロース及びキサンタンガムの少なくとも１種を含む、＜１＞～＜５＞のいずれか１項に記載の二次電池用バインダー組成物。
＜７＞
　上記水溶性高分子（Ｘ）の分子量分布が５．０以下である、＜１＞～＜６＞のいずれか１項に記載の二次電池用バインダー組成物。
＜８＞
　上記水溶性高分子（Ｘ）の引張弾性率が４０００ＭＰａ以上である、＜１＞～＜７＞のいずれか１項に記載の二次電池用バインダー組成物。
＜９＞
　上記重合体粒子を構成する重合体が、共役ジエン成分、エチレン性不飽和カルボン酸成分、シアノ基含有エチレン性モノマー成分及び芳香族ビニルモノマー成分の少なくとも１種を含む重合体である、＜１＞～＜８＞のいずれか１項に記載の二次電池用バインダー組成物。
＜１０＞
　上記重合体粒子のガラス転移温度が－５０～１５０℃である、＜１＞～＜９＞のいずれか１項に記載の二次電池用バインダー組成物。
＜１１＞
　＜１＞～＜１０＞のいずれか１項に記載の二次電池用バインダー組成物と、周期律表第１族又は第２族に属する金属のイオンの挿入放出が可能な活物質と、導電助剤とを含有する、電極用組成物。
＜１２＞
　上記活物質がケイ素系活物質を含む、＜１１＞に記載の電極用組成物。
＜１３＞
　＜１１＞又は＜１２＞に記載の電極用組成物を用いて形成された層を有する電極シート。
＜１４＞
　正極活物質層及び負極活物質層の少なくとも１つの層が、＜１１＞又は＜１２＞に記載の電極用組成物を用いて形成された層である、二次電池。
＜１５＞
　＜１１＞又は＜１２＞に記載の電極用組成物を用いて電極活物質層を形成することを含む、電極シートの製造方法。
＜１６＞
　＜１５＞に記載の製造方法により得られた電極シートを二次電池の電極として組み込むことを含む、二次電池の製造方法。 That is, the above-mentioned problems of the present invention were solved by the following means.
<1>
A binder composition for a secondary battery comprising a water-soluble polymer (X), a water-soluble compound (Y), polymer particles, and water,
The water-soluble polymer (X) is a polymer containing a component represented by the following general formula (B-2),
The binder composition has a tensile modulus of 1500 to 9800 MPa, and
A binder composition for secondary batteries that satisfies the following <Storage Modulus Characteristics 1>.
<Storage modulus characteristics 1>
Carbon-coated silicon oxide in powder form with an average particle size of 1 to 10 μm and a specific surface area of 1 to 10 m 2 /g; and powdered silicon oxide with an average particle size of 15 to 25 μm and a specific surface area of 1 to 10 m 2 /g. In a slurry prepared by mixing graphite, acetylene black in powder form with an average particle size of 30 to 40 nm and a specific surface area of 65 to 75 m 2 /g, and the above binder composition for secondary batteries in the following quantitative ratio, Characteristics such that the difference between the storage elastic modulus G A ' at a shear strain of 0.01% and the storage elastic modulus G B ' at a shear strain of 10% of the slurry is 100 to 1000 Pa.
-Quantity ratio-
With respect to 100 parts by mass of the total solid content in the slurry, the content of the carbon-coated silicon oxide is 17.8 parts by mass, the content of the graphite is 71.2 parts by mass, and the content of the acetylene black is 6 parts by mass. The solid content in the binder composition for secondary batteries is 5 parts by mass, and the total solid content in the slurry is 52% by mass.
Figure JPOXMLDOC01-appb-I000002
In the general formula (B-2), R 21 to R 23 represent a hydrogen atom, a cyano group, or an alkyl group having 1 to 6 carbon atoms, and R 24 represents a hydrogen atom, an acyl group, a hydroxy group, a phenyl group, or a carboxy group. and L 21 represents a single bond, an alkylene group having 1 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom, a sulfur atom, a carbonyl group, an imino group, or a linking group combining these. * indicates a binding site for incorporation into the main chain of the water-soluble polymer (X).
<2>
The binder composition for a secondary battery according to <1>, wherein the content of the component represented by the general formula (B-2) in the water-soluble polymer (X) is 80% by mass or more.
<3>
The binder composition for a secondary battery according to <1> or <2>, wherein the component represented by the general formula (B-2) includes a (meth)acrylamide component.
<4>
In any one of <1> to <3>, wherein the water-soluble polymer (X) is a polymer further containing at least one of an acrylonitrile component, an N-vinyl-2-pyrrolidone component, and a styrene component. The binder composition for secondary batteries described above.
<5>
The binder composition for a secondary battery according to any one of <1> to <4>, wherein the water-soluble compound (Y) contains a polysaccharide.
<6>
For the secondary battery according to any one of <1> to <5>, wherein the water-soluble compound (Y) contains at least one of carboxymethyl cellulose, cellulose nanofiber, hydroxyethyl cellulose, hydroxypropyl cellulose, and xanthan gum. Binder composition.
<7>
The binder composition for a secondary battery according to any one of <1> to <6>, wherein the water-soluble polymer (X) has a molecular weight distribution of 5.0 or less.
<8>
The binder composition for a secondary battery according to any one of <1> to <7>, wherein the water-soluble polymer (X) has a tensile modulus of 4000 MPa or more.
<9>
<1> The polymer constituting the polymer particles is a polymer containing at least one of a conjugated diene component, an ethylenically unsaturated carboxylic acid component, a cyano group-containing ethylenic monomer component, and an aromatic vinyl monomer component. ~ The binder composition for secondary batteries according to any one of <8>.
<10>
The binder composition for a secondary battery according to any one of <1> to <9>, wherein the polymer particles have a glass transition temperature of -50 to 150°C.
<11>
The binder composition for a secondary battery according to any one of <1> to <10>, an active material capable of inserting and releasing metal ions belonging to Group 1 or Group 2 of the periodic table, and a conductive material. An electrode composition containing an auxiliary agent.
<12>
The electrode composition according to <11>, wherein the active material includes a silicon-based active material.
<13>
An electrode sheet having a layer formed using the electrode composition according to <11> or <12>.
<14>
A secondary battery, wherein at least one of the positive electrode active material layer and the negative electrode active material layer is a layer formed using the electrode composition described in <11> or <12>.
<15>
A method for producing an electrode sheet, the method comprising forming an electrode active material layer using the electrode composition according to <11> or <12>.
<16>
A method for manufacturing a secondary battery, comprising incorporating an electrode sheet obtained by the manufacturing method according to <15> as an electrode of the secondary battery.
　本発明において、「水溶性高分子」とは、２０℃において水に対する溶解度が１０ｇ／Ｌ－Ｈ２Ｏ以上であるポリマー、すなわち、２０℃において水１リットルに対して１０ｇ以上溶解するポリマーを意味する。「水溶性高分子」の上記溶解度は１００ｇ／Ｌ－Ｈ２Ｏ以上であることが好ましい。
　本発明において、「水溶性化合物」とは、２０℃において水に対する溶解度が１０ｇ／Ｌ－Ｈ２Ｏ以上である化合物、すなわち、２０℃において水１リットルに対して１０ｇ以上溶解する化合物を意味する。「水溶性化合物」の上記溶解度は１００ｇ／Ｌ－Ｈ２Ｏ以上であることが好ましい。
　本発明において、「～」を用いて表される数値範囲は、「～」の前後に記載される数値を下限値及び上限値として含む範囲を意味する。
　本発明において化合物、構成成分又は置換基の表示については、本発明の効果を奏する範囲で、構造の一部を変化させたものを含む意味である。更に、本発明において置換又は無置換を明記していない化合物又は構成成分については、本発明の効果を奏する範囲で、任意の置換基を有していてもよい意味である。このことは、置換基（例えば、「アルキル基」、「メチル基」、「メチル」等のように表現される基）及び連結基（例えば、「アルキレン基」、「メチレン基」、「メチレン」等のように表現される基）についても同様である。このような任意の置換基のうち、本発明において好ましい置換基は、後述の置換基群Ｔから選択される置換基である。
　本発明において、特定の符号又は式で示された置換基若しくは連結基等（以下、置換基等という）が複数あるとき、又は複数の置換基等を同時に規定するときには、特段の断りがない限り、それぞれの置換基等は互いに同一でも異なっていてもよい。このことは、ポリマーの構成成分についても同様である。
　本発明において、各成分は１種含有されていてもよく、２種以上含有されていてもよい。
　本発明において、（メタ）アクリルとは、アクリル及びメタアクリルの一方又は両方を意味する。（メタ）アクリレートについても同様である。
　本発明において「二次電池」とは、充放電により電解質を介して正負極間をイオンが通過し、正負極においてエネルギーを貯蔵、放出するデバイス全般を意味する。すなわち、本発明において二次電池という場合、電池とキャパシタ（例えば、リチウムイオンキャパシタ）の両方を包含する意味である。エネルギー貯蔵量の観点から、本発明の二次電池は電池用途に用いること（キャパシタでないこと）が好ましい。
　二次電池は、用いる電解質に応じて水系二次電池と非水系二次電池とに大別でき、本発明においては、非水系二次電池が好ましい。本発明において「水系二次電池」とは、電解質として水系電解液を用いた二次電池を意味する。本発明において「非水系二次電池」とは、非水電解液二次電池と全固体二次電池とを含む意味である。本発明において「非水電解液二次電池」とは、電解質として非水電解液を用いた二次電池を意味する。本発明において「非水電解液」とは、水を実質的に含まない電解液を意味する。水を実質的に含まない電解液とは、「非水電解液」が本発明の効果を妨げない範囲で微量の水を含んでいてもよいことを意味する。本発明において「非水電解液」は、水の濃度が２００ｐｐｍ（質量基準）以下であり、１００ｐｐｍ以下が好ましく２０ｐｐｍ以下がより好ましい。なお、非水電解液を完全に無水とすることは現実的に困難であり、通常は水が１ｐｐｍ以上含まれる。本発明において「全固体二次電池」とは、電解質として液を用いず、無機固体電解質、固体状ポリマー電解質等の固体電解質を用いた二次電池を意味する。
　本発明において、ある基の炭素数を規定する場合、この炭素数は、本発明ないし本明細書において特段の断りのない限りは、基そのものの炭素数を意味する。つまり、この基が更に置換基を有する形態である場合、この置換基の炭素数は含まずに数えた場合の炭素数を意味する。
　本発明において、含有量又は含有割合を記載する場合に使用する「固形分」とは、後述する水及び液媒体以外の成分を意味する。
　本発明において、「平均粒径」とは、体積基準のメジアン径Ｄ５０を意味する。 In the present invention, "water-soluble polymer" means a polymer whose solubility in water is 10 g/L-H 2 O or more at 20°C, that is, a polymer that dissolves 10 g or more in 1 liter of water at 20°C. do. The solubility of the "water-soluble polymer" is preferably 100 g/L-H 2 O or more.
In the present invention, the term "water-soluble compound" refers to a compound that has a solubility in water of 10 g/L-H 2 O or more at 20°C, that is, a compound that dissolves 10 g or more in 1 liter of water at 20°C. . The solubility of the "water-soluble compound" is preferably 100 g/L-H 2 O or more.
In the present invention, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as lower and upper limits.
In the present invention, the expression of a compound, a constituent component, or a substituent is meant to include those whose structures are partially changed within the range that exhibits the effects of the present invention. Further, in the present invention, compounds or constituent components that are not specified as being substituted or unsubstituted may have any substituent as long as the effects of the present invention are achieved. This applies to substituents (e.g., groups expressed as "alkyl group,""methylgroup,""methyl," etc.) and linking groups (e.g., "alkylene group,""methylenegroup,""methylenegroup," etc.) The same applies to groups expressed as such. Among such arbitrary substituents, preferred substituents in the present invention are substituents selected from substituent group T described below.
In the present invention, when there are multiple substituents or linking groups, etc. (hereinafter referred to as substituents, etc.) indicated by a specific symbol or formula, or when multiple substituents, etc. are specified at the same time, unless otherwise specified, , each substituent, etc. may be the same or different from each other. This also applies to the constituent components of the polymer.
In the present invention, one type of each component may be contained, or two or more types of each component may be contained.
In the present invention, (meth)acrylic means one or both of acrylic and methacrylic. The same applies to (meth)acrylate.
In the present invention, the term "secondary battery" refers to any device in which ions pass between positive and negative electrodes via an electrolyte during charging and discharging, and energy is stored and released at the positive and negative electrodes. That is, in the present invention, the term "secondary battery" includes both a battery and a capacitor (for example, a lithium ion capacitor). From the viewpoint of energy storage capacity, the secondary battery of the present invention is preferably used for battery applications (not as a capacitor).
Secondary batteries can be roughly classified into aqueous secondary batteries and non-aqueous secondary batteries depending on the electrolyte used, and in the present invention, non-aqueous secondary batteries are preferred. In the present invention, the term "aqueous secondary battery" refers to a secondary battery using an aqueous electrolyte as an electrolyte. In the present invention, the term "non-aqueous secondary battery" includes non-aqueous electrolyte secondary batteries and all-solid-state secondary batteries. In the present invention, a "non-aqueous electrolyte secondary battery" means a secondary battery using a non-aqueous electrolyte as an electrolyte. In the present invention, the term "non-aqueous electrolyte" means an electrolyte that does not substantially contain water. An electrolytic solution that does not substantially contain water means that the "non-aqueous electrolytic solution" may contain a trace amount of water as long as the effects of the present invention are not impaired. In the present invention, the "nonaqueous electrolyte" has a water concentration of 200 ppm or less (based on mass), preferably 100 ppm or less, and more preferably 20 ppm or less. Note that it is practically difficult to make the nonaqueous electrolyte completely anhydrous, and it usually contains 1 ppm or more of water. In the present invention, the term "all-solid secondary battery" refers to a secondary battery that uses a solid electrolyte such as an inorganic solid electrolyte or a solid polymer electrolyte without using a liquid as an electrolyte.
In the present invention, when specifying the number of carbon atoms in a certain group, this number of carbon atoms means the number of carbon atoms in the group itself unless otherwise specified in the present invention or this specification. In other words, when this group further has a substituent, the number of carbon atoms is counted without including the number of carbon atoms of this substituent.
In the present invention, the "solid content" used when describing the content or content ratio means components other than water and the liquid medium described below.
In the present invention, the "average particle size" means the volume-based median diameter D50.
　本発明の二次電池用バインダー組成物、電極用組成物及び電極シートは、充放電時の体積変化の大きな電極活物質を用いた場合でも、得られる二次電池のサイクル寿命を十分に長期化することができる。また、本発明の電極シートは、密着性に優れる。
　本発明の二次電池は、充放電時の体積変化の大きな電極活物質を用いた場合にも、十分に長いサイクル寿命を実現できる。
　本発明の電極シートの製造方法によれば、本発明の上記電極シートを得ることができる。また、本発明の二次電池の製造方法によれば、本発明の上記二次電池を得ることができる。 The binder composition for secondary batteries, the composition for electrodes, and the electrode sheet of the present invention sufficiently extend the cycle life of the resulting secondary batteries even when using electrode active materials that exhibit large volume changes during charging and discharging. can do. Moreover, the electrode sheet of the present invention has excellent adhesiveness.
The secondary battery of the present invention can achieve a sufficiently long cycle life even when using an electrode active material that exhibits a large volume change during charging and discharging.
According to the method for manufacturing an electrode sheet of the present invention, the above electrode sheet of the present invention can be obtained. Moreover, according to the method for manufacturing a secondary battery of the present invention, the above-mentioned secondary battery of the present invention can be obtained.
図１は、本発明に係る二次電池の一実施形態について、基本的な積層構成を模式化して示す縦断面図である。FIG. 1 is a vertical cross-sectional view schematically showing the basic stacked structure of an embodiment of a secondary battery according to the present invention.
［二次電池用バインダー組成物］
　本発明の二次電池用バインダー組成物（以降、「本発明のバインダー組成物」とも称す。）は、水溶性高分子（Ｘ）と、水溶性化合物（Ｙ）と、重合体粒子と、水とを含有する。本発明のバインダー組成物は、好ましくは非水系二次電池、より好ましくは非水電解液二次電池を構成する部材ないし構成層の形成に用いるのに好適である。本発明のバインダー組成物に含まれる水は、液媒体として機能する。典型的には、本発明のバインダー組成物は、本発明のバインダー組成物と電極活物質（正極活物質又は負極活物質、これらを合わせて、単に「活物質」とも称す。）と導電助剤とを含有する電極用組成物として、二次電池の電極（正極又は負極）における電極活物質層（正極活物質層又は負極活物質層）の形成に好適に用いることができる。 [Binder composition for secondary batteries]
The binder composition for secondary batteries of the present invention (hereinafter also referred to as "the binder composition of the present invention") comprises a water-soluble polymer (X), a water-soluble compound (Y), polymer particles, and water. Contains. The binder composition of the present invention is preferably used for forming members or constituent layers constituting a non-aqueous secondary battery, more preferably a non-aqueous electrolyte secondary battery. The water contained in the binder composition of the present invention functions as a liquid medium. Typically, the binder composition of the present invention includes the binder composition of the present invention, an electrode active material (a positive electrode active material or a negative electrode active material, together also simply referred to as "active material"), and a conductive additive. As an electrode composition containing the above, it can be suitably used for forming an electrode active material layer (positive electrode active material layer or negative electrode active material layer) in an electrode (positive electrode or negative electrode) of a secondary battery.
　本発明のバインダー組成物が含有する水溶性高分子（Ｘ）及び重合体粒子は、例えば、本発明のバインダー組成物と固体粒子（電極活物質、導電助剤等）とを混合して形成した層中において、主として、これらの固体粒子同士を結着させる結着剤（バインダー）として機能すると考えられる。また、集電体と固体粒子とを結着させる結着剤としても機能し得る。水溶性高分子（Ｘ）及び重合体粒子の固体粒子及び集電体に対する吸着は、物理的吸着だけでなく、化学的吸着（化学結合形成による吸着、電子の授受による吸着等）も含む。
　一方、本発明のバインダー組成物が含有する水溶性化合物（Ｙ）は、主として、本発明のバインダー組成物中で増粘剤（分散剤）として機能するものと考えられる。 The water-soluble polymer (X) and polymer particles contained in the binder composition of the present invention are, for example, formed by mixing the binder composition of the present invention and solid particles (electrode active material, conductive aid, etc.). It is thought that in the layer, it mainly functions as a binding agent (binder) that binds these solid particles together. It can also function as a binder that binds the current collector and solid particles. The adsorption of water-soluble polymer (X) and polymer particles to solid particles and current collectors includes not only physical adsorption but also chemical adsorption (adsorption due to chemical bond formation, adsorption due to transfer of electrons, etc.).
On the other hand, the water-soluble compound (Y) contained in the binder composition of the present invention is considered to mainly function as a thickener (dispersant) in the binder composition of the present invention.
　本発明のバインダー組成物の引張弾性率は１５００～９８００ＭＰａである。集電体との密着性を高め、かつ電極活物質層の体積変化を効果的に抑制してサイクル特性を向上させる観点から、バインダー組成物の引張弾性率は、１６００～８０００ＭＰａであることが好ましく、１７００～７０００ＭＰａがより好ましく、１８００～６０００ＭＰａが更に好ましい。
　本発明において、上記引張弾性率は後述する実施例に記載の方法により得られる値とする。後述する実施例に示されるように、上記引張弾性率は、本発明のバインダー組成物を膜厚０．１０ｍｍの塗布膜として測定される。
　本発明のバインダー組成物の引張弾性率は、水溶性高分子（Ｘ）、水溶性化合物（Ｙ）、及び重合体粒子の種類、含有量等を調整することにより上記範囲内とすることができる。 The tensile modulus of the binder composition of the present invention is 1500 to 9800 MPa. From the viewpoint of increasing the adhesion with the current collector and effectively suppressing the volume change of the electrode active material layer to improve the cycle characteristics, the tensile modulus of the binder composition is preferably 1600 to 8000 MPa. , 1700 to 7000 MPa is more preferable, and 1800 to 6000 MPa is still more preferable.
In the present invention, the above-mentioned tensile modulus is a value obtained by a method described in Examples described later. As shown in the Examples described later, the above tensile modulus is measured using the binder composition of the present invention as a coating film having a thickness of 0.10 mm.
The tensile modulus of the binder composition of the present invention can be controlled within the above range by adjusting the type, content, etc. of the water-soluble polymer (X), the water-soluble compound (Y), and the polymer particles. .
　本発明のバインダー組成物は、下記＜貯蔵弾性率特性１＞を満たす。
＜貯蔵弾性率特性１＞
　平均粒径が１～１０μｍかつ比表面積１～１０ｍ２／ｇの粉末状であるカーボンコートされた酸化ケイ素と、平均粒径が１５～２５μｍかつ比表面積１～１０ｍ２／ｇの粉末状である黒鉛と、平均粒径が３０～４０ｎｍかつ比表面積６５～７５ｍ２／ｇの粉末状であるアセチレンブラックと、上記二次電池用バインダー組成物とを下記量比となるよう調製したスラリーにおいて、該スラリーのせん断ひずみ０．０１％における貯蔵弾性率ＧＡ’とせん断ひずみ１０％における貯蔵弾性率ＧＢ’との差が１００～１０００Ｐａとなる特性。
－量比－
　スラリー中の全固形分１００質量部に対して、上記カーボンコートされた酸化ケイ素の含有量を１７．８質量部、上記黒鉛の含有量を７１．２質量部、上記アセチレンブラックの含有量を６質量部、上記二次電池用バインダー組成物の固形分の含有量を５質量部とし、かつスラリー中の全固形分量を５２質量％とする。
　本発明において「スラリー」とは、実施例の混合方法のように、各成分を十分に均一混合して得られる分散液組成物である。本発明において、「スラリー中の全固形分量を５２質量％とする」とは、全固形分量が５２質量％よりも濃い状態から５２質量％へと調整する場合は水で希釈することとし、全固形分量が５２質量％よりも薄い状態から５２質量％へと調整する場合は溶媒を蒸発させる等して濃縮することとする。溶媒の蒸発は、例えば真空乾燥、減圧などにより行うことができる。
　本発明において「せん断ひずみ０．０１％における貯蔵弾性率ＧＡ’とせん断ひずみ１０％における貯蔵弾性率ＧＢ’との差」とは、せん断ひずみ０．０１％における貯蔵弾性率ＧＡ’からせん断ひずみ１０％における貯蔵弾性率ＧＢ’を引いた値（ＧＡ’－ＧＢ’）を意味する。
　その他、上記＜貯蔵弾性率特性１＞の充足性の判断は、レオメータを用いたひずみ分散測定により行うことができる。詳細な測定条件は後述する実施例に記載の通りである。
　なお、上記＜貯蔵弾性率特性１＞で用いるカーボンコートされた酸化ケイ素、黒鉛、及びアセチレンブラックそれぞれの平均粒径（体積基準のメジアン径Ｄ５０）は、カーボンコートされた酸化ケイ素では１～１０μｍ（好ましくは２～７μｍ）、黒鉛では１５～２５μｍ（好ましくは１７～２２μｍ）、アセチレンブラックでは３０～４０ｎｍ（好ましくは３２～３７ｎｍ）の範囲にある。
　また、上記＜貯蔵弾性率特性１＞で用いるカーボンコートされた酸化ケイ素、黒鉛、及びアセチレンブラックそれぞれの比表面積は、カーボンコートされた酸化ケイ素では１～１０ｍ２／ｇ（好ましくは２～７ｍ２／ｇ）、黒鉛では１～１０ｍ２／ｇ（好ましくは２～７ｍ２／ｇ）、アセチレンブラックでは６５～７５ｍ２／ｇ（好ましくは６６～７０ｍ２／ｇ）の範囲にある。
　これらの平均粒径及び比表面積の範囲内であれば、得られる貯蔵弾性率の値は実質的に同じである。
　また、上記＜貯蔵弾性率特性１＞で用いるカーボンコートされた酸化ケイ素、黒鉛、及びアセチレンブラックにおける「粉末状」とは、粉末（一次粒子、及び／又は一次粒子が凝集した凝集体（二次粒子）を含む粉）の形状であることを表し、例えば、粉末をプレスしたものや顆粒状のもの等は含まない。
　なお、上記＜貯蔵弾性率特性１＞で用いるカーボンコートされた酸化ケイ素とは、酸化ケイ素（ＳｉＯｘ（０＜ｘ≦１．５））の表面に炭素系材料が担持されたものを表し、カーボンコートされた酸化ケイ素中に占める炭素元素の含有量の割合は０．５～５質量％（好ましくは１～３質量％）の範囲にある。なお、上記＜貯蔵弾性率特性１＞で用いるカーボンコートされた酸化ケイ素は、金属元素をドープされていない（例えば、カーボンコートと金属元素のドープとの両方が施された酸化ケイ素ではない）ものとする。
　カーボンコートされた酸化ケイ素の市販品として、例えば、大阪チタニウムテクノロジー社製のカーボンコートされた酸化ケイ素粉末（グレード：ＳｉＯ　ＮＣ、平均粒径：５μｍ、比表面積：２．６ｍ２／ｇ）、黒鉛の市販品として、例えば、昭和電工マテリアルズ社製の塊状人造黒鉛粉末（商品名：ＭＡＧ－Ｄ、平均粒径：２１μｍ、比表面積：４ｍ２／ｇ）、アセチレンブラックの市販品として、例えば、デンカ社製のアセチレンブラック（商品名：デンカブラック、グレード：粉状品、平均粒径：３５ｎｍ、比表面積：６８ｍ２／ｇ）を用いることができる。 The binder composition of the present invention satisfies the following <Storage modulus characteristic 1>.
<Storage modulus characteristics 1>
Carbon-coated silicon oxide in powder form with an average particle size of 1 to 10 μm and a specific surface area of 1 to 10 m 2 /g; and powdered silicon oxide with an average particle size of 15 to 25 μm and a specific surface area of 1 to 10 m 2 /g. In a slurry prepared by mixing graphite, acetylene black in powder form with an average particle size of 30 to 40 nm and a specific surface area of 65 to 75 m 2 /g, and the above binder composition for secondary batteries in the following quantitative ratio, Characteristics such that the difference between the storage elastic modulus G A ' at a shear strain of 0.01% and the storage elastic modulus G B ' at a shear strain of 10% of the slurry is 100 to 1000 Pa.
-Quantity ratio-
With respect to 100 parts by mass of the total solid content in the slurry, the content of the carbon-coated silicon oxide is 17.8 parts by mass, the content of the graphite is 71.2 parts by mass, and the content of the acetylene black is 6 parts by mass. The solid content of the binder composition for secondary batteries is 5 parts by mass, and the total solid content in the slurry is 52% by mass.
In the present invention, "slurry" refers to a dispersion composition obtained by thoroughly and uniformly mixing each component as in the mixing method of the Examples. In the present invention, "total solid content in the slurry is 52% by mass" means that when adjusting the total solid content from a state thicker than 52% by mass to 52% by mass, dilution with water is required. When adjusting the solid content from a state where the solid content is thinner than 52% by mass to 52% by mass, the solid content is concentrated by evaporating the solvent or the like. The solvent can be evaporated by, for example, vacuum drying or reduced pressure.
In the present invention, "the difference between the storage modulus GA' at a shear strain of 0.01% and the storage modulus GB ' at a shear strain of 10 % " means the difference between the storage modulus GA ' at a shear strain of 0.01% It means the value obtained by subtracting the storage modulus G B ' at a shear strain of 10% (G A '-G B ').
In addition, the sufficiency of the above <Storage Modulus Characteristics 1> can be determined by strain dispersion measurement using a rheometer. Detailed measurement conditions are as described in Examples described later.
The average particle size (volume-based median diameter D50) of carbon-coated silicon oxide, graphite, and acetylene black used in <Storage modulus characteristics 1> above is 1 to 10 μm (volume-based median diameter D50). The range is preferably 2 to 7 μm), 15 to 25 μm (preferably 17 to 22 μm) for graphite, and 30 to 40 nm (preferably 32 to 37 nm) for acetylene black.
Further, the specific surface area of each of carbon-coated silicon oxide, graphite, and acetylene black used in <Storage modulus characteristics 1> is 1 to 10 m 2 /g (preferably 2 to 7 m 2 ) for carbon-coated silicon oxide. /g), 1 to 10 m 2 /g (preferably 2 to 7 m 2 /g) for graphite, and 65 to 75 m 2 /g (preferably 66 to 70 m 2 /g) for acetylene black.
Within these average particle diameter and specific surface area ranges, the obtained storage modulus values are substantially the same.
In addition, "powder" in carbon-coated silicon oxide, graphite, and acetylene black used in <Storage Modulus Characteristics 1> above refers to powder (primary particles) and/or aggregates of primary particles (secondary particles). For example, it does not include pressed powder or granules.
The carbon-coated silicon oxide used in <Storage Modulus Characteristics 1> above refers to silicon oxide (SiO x (0<x≦1.5)) with a carbon-based material supported on its surface. The content of carbon element in the carbon-coated silicon oxide is in the range of 0.5 to 5% by mass (preferably 1 to 3% by mass). Note that the carbon-coated silicon oxide used in <Storage Modulus Characteristics 1> above is not doped with a metal element (for example, it is not silicon oxide coated with both a carbon coat and a metal element dope). shall be.
Commercial products of carbon-coated silicon oxide include, for example, carbon-coated silicon oxide powder (grade: SiO NC, average particle size: 5 μm, specific surface area: 2.6 m 2 /g) manufactured by Osaka Titanium Technology Co., Ltd., and graphite. Commercially available products include, for example, massive artificial graphite powder (trade name: MAG-D, average particle size: 21 μm, specific surface area: 4 m 2 /g) manufactured by Showa Denko Materials, and commercially available acetylene black products, such as: Acetylene black manufactured by Denka Corporation (trade name: Denka Black, grade: powder, average particle size: 35 nm, specific surface area: 68 m 2 /g) can be used.
　上記せん断ひずみ０．０１％における貯蔵弾性率ＧＡ’とせん断ひずみ１０％における貯蔵弾性率ＧＢ’との差（ＧＡ’－ＧＢ’）は、１００～８００Ｐａであることが好ましく、１００～６００Ｐａであることがより好ましく、１１０～４００Ｐａであることが更に好ましく、１２０～３００Ｐａであることが特に好ましい。
　本発明のバインダー組成物の貯蔵弾性率の差（ＧＡ’－ＧＢ’）は、水溶性高分子（Ｘ）、水溶性化合物（Ｙ）、及び重合体粒子の種類、含有量等を調整することにより上記範囲内とすることができる。固体粒子の分散性を高める観点からは、上記貯蔵弾性率の差は大きい方が好ましい。 The difference between the storage elastic modulus G A ′ at a shear strain of 0.01% and the storage elastic modulus G B ′ at a shear strain of 10% (G A ′-G B ′) is preferably 100 to 800 Pa, and 100 It is more preferably from 110 to 400 Pa, even more preferably from 120 to 300 Pa.
The difference in storage modulus ( GA' - GB ') of the binder composition of the present invention can be determined by adjusting the types, contents, etc. of the water-soluble polymer (X), water-soluble compound (Y), and polymer particles. By doing so, it can be kept within the above range. From the viewpoint of improving the dispersibility of solid particles, it is preferable that the difference in storage modulus is large.
　本発明のバインダー組成物の、せん断ひずみ０．０１％における貯蔵弾性率ＧＡ’は、上記差（ＧＡ’－ＧＢ’）が１００～１０００Ｐａとなれば特に限定されず、１０１～１５００Ｐａであることが好ましく、１０５～１３００Ｐａであることがより好ましく、１１０～１２００Ｐａであることが更に好ましい。
　本発明のバインダー組成物の、せん断ひずみ１０％における貯蔵弾性率ＧＢ’は、上記差（ＧＡ’－ＧＢ’）が１００～１０００Ｐａとなれば特に限定されず、１～５００Ｐａであることが好ましく、５～３００Ｐａであることがより好ましく、１０～２００Ｐａであることが更に好ましい。 The storage modulus G A ′ of the binder composition of the present invention at a shear strain of 0.01% is not particularly limited as long as the above difference (G A ′-G B ′) is 100 to 1000 Pa, and is 101 to 1500 Pa. It is preferably 105 to 1300 Pa, more preferably 110 to 1200 Pa.
The storage modulus GB' at a shear strain of 10% of the binder composition of the present invention is not particularly limited as long as the above difference (G A' -G B ') is 100 to 1000 Pa , and should be 1 to 500 Pa. The pressure is preferably 5 to 300 Pa, more preferably 10 to 200 Pa.
　本発明のバインダー組成物は、例えば、活物質及び導電助剤を含む電極用組成物とした上で電極シートを作成して、これを二次電池の電極に適用することで、電極シートの密着性を高め、かつ、二次電池のサイクル特性を向上させることができる。この理由は定かではないが、以下のように考えられる。
　本発明のバインダー組成物を活物質及び導電助剤と混合した際のせん断ひずみの程度と貯蔵弾性率とが特定の関係に制御されることにより、本発明のバインダー組成物を電極用組成物に用いた場合に活物質及び導電助剤等の固体粒子をより高い均一性で分散でき、これら固体粒子による導電ネットワーク構造の形成に効果的に寄与する（導電ネットワーク構造の局在化を抑制する）ことが、サイクル特性向上の一因と考えられる。また、固体分子等が均一分散していることにより、集電体に対する剥離強度も高めることができると考えられる。更に、水溶性高分子（Ｘ）がその特定の構造に起因して固体粒子等と相互作用し、かつバインダー組成物全体として所定の引張弾性率を有し、これらが電極活物質層の体積変化に抑制的に作用し、重合体粒子の固体粒子等に対する追従性と結着性を無理なく十分に引き出すことができることも、サイクル特性向上の一因と考えられる。 For example, the binder composition of the present invention can be made into an electrode composition containing an active material and a conductive additive, and then an electrode sheet can be created, and this can be applied to an electrode of a secondary battery, so that the electrode sheet can be tightly bonded. It is possible to improve the cycle characteristics of the secondary battery. Although the reason for this is not certain, it is thought to be as follows.
By controlling the degree of shear strain and storage modulus to have a specific relationship when the binder composition of the present invention is mixed with an active material and a conductive additive, the binder composition of the present invention can be used as an electrode composition. When used, solid particles such as active materials and conductive additives can be dispersed with higher uniformity, and these solid particles effectively contribute to the formation of a conductive network structure (suppressing localization of the conductive network structure). This is considered to be one of the reasons for the improvement in cycle characteristics. Furthermore, it is thought that the uniform dispersion of solid molecules and the like makes it possible to increase the peel strength against the current collector. Furthermore, due to its specific structure, the water-soluble polymer (X) interacts with solid particles, etc., and the binder composition as a whole has a predetermined tensile modulus, which causes a change in the volume of the electrode active material layer. It is also thought that one of the reasons for the improvement in cycle characteristics is that the polymer particles have a suppressive effect on solid particles and the like, and can easily and sufficiently bring out the conformability and binding ability of the polymer particles to solid particles.
　以下に本発明のバインダー組成物が含む成分について説明する。 The components contained in the binder composition of the present invention will be explained below.
（水溶性高分子（Ｘ））
　水溶性高分子（Ｘ）は、下記一般式（Ｂ－２）で表される構成成分を含む重合体である。 (Water-soluble polymer (X))
The water-soluble polymer (X) is a polymer containing a component represented by the following general formula (B-2).
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000003
　一般式（Ｂ－２）中、Ｒ２１～Ｒ２３は水素原子、シアノ基又は炭素数１～６のアルキル基を示す。この炭素数１～６のアルキル基は直鎖でも分岐を有してもよい。この炭素数１～６のアルキル基は、炭素数１～４のアルキル基が好ましく、メチル又はエチルがより好ましく、メチルが更に好ましい。
　Ｒ２１及びＲ２２としては、水素原子が好ましい。
　Ｒ２３としては、水素原子又はメチルが好ましく、水素原子がより好ましい。
　Ｒ２４は水素原子、アシル基（アルキルカルボニル基）、ヒドロキシ基、フェニル基又はカルボキシ基を示す。アシル基中のアルキル基としては、例えば、後述の置換基群Ｔにおけるアルキル基が挙げられ、直鎖でも分岐を有してもよく、好ましくはＲ２１～Ｒ２３として採り得る炭素数１～６のアルキル基を採用することができる。
　Ｒ２４としては、水素原子又はヒドロキシ基が好ましく、水素原子がより好ましい。
　Ｌ２１は単結合、炭素数１～１６のアルキレン基、炭素数６～１２のアリーレン基、酸素原子（－Ｏ－）、硫黄原子（－Ｓ－）、カルボニル基（＞Ｃ＝Ｏ）若しくはイミノ基（＞ＮＲＮ）、又はこれらを組み合わせた連結基を示す。また、Ｌ２１は後述の置換基群Ｔから選ばれる置換基を有していてもよく、この置換基としては、ヒドロキシ基が好ましい。
　上記ＲＮは、水素原子、アルキル基を示す。
　Ｌ２１が単結合以外の連結基を示す場合、Ｌ２１の化学式量は１４～２０００が好ましく、１４～５００がより好ましく、２８～２００が更に好ましい。Ｌ２１が有しうる炭素数１～１６のアルキレン基は直鎖でも分岐を有してもよい。このアルキレン基の炭素数は１～１２が好ましく、１～１０がより好ましく、１～６が更に好ましく、１～４が特に好ましい。
　Ｌ２１としては、単結合、メチレン、エチレン、プロピレン、２－ヒドロキシプロピレン又はブチレンが好ましく、単結合又はエチレンがより好ましく、単結合が更に好ましい。
　＊は上記ポリマー（水溶性高分子（Ｘ））主鎖中に組み込まれるための結合部位を示す。 In general formula (B-2), R 21 to R 23 represent a hydrogen atom, a cyano group, or an alkyl group having 1 to 6 carbon atoms. This alkyl group having 1 to 6 carbon atoms may be linear or branched. The alkyl group having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 4 carbon atoms, more preferably methyl or ethyl, and even more preferably methyl.
A hydrogen atom is preferable as R 21 and R 22 .
R23 is preferably a hydrogen atom or methyl, more preferably a hydrogen atom.
R24 represents a hydrogen atom, an acyl group (alkylcarbonyl group), a hydroxy group, a phenyl group, or a carboxy group. Examples of the alkyl group in the acyl group include the alkyl group in substituent group T described below, which may be linear or branched, and preferably has 1 to 6 carbon atoms, which can be taken as R 21 to R 23 . An alkyl group of can be employed.
R24 is preferably a hydrogen atom or a hydroxy group, more preferably a hydrogen atom.
L21 is a single bond, an alkylene group having 1 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom (-O-), a sulfur atom (-S-), a carbonyl group (>C=O), or an imino group. Indicates a group (>NR N ) or a linking group that is a combination of these. Further, L 21 may have a substituent selected from substituent group T described below, and this substituent is preferably a hydroxy group.
The above R N represents a hydrogen atom or an alkyl group.
When L 21 represents a linking group other than a single bond, the chemical formula weight of L 21 is preferably from 14 to 2,000, more preferably from 14 to 500, even more preferably from 28 to 200. The alkylene group having 1 to 16 carbon atoms that L 21 may have may be linear or branched. The alkylene group preferably has 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, even more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms.
L 21 is preferably a single bond, methylene, ethylene, propylene, 2-hydroxypropylene or butylene, more preferably a single bond or ethylene, and even more preferably a single bond.
* indicates a bonding site for incorporation into the main chain of the above polymer (water-soluble polymer (X)).
　上記一般式（Ｂ－２）で表される構成成分の具体例としては、（メタ）アクリルアミド成分；Ｎ－（２－ヒドロキシエチル）（メタ）アクリルアミド成分等のＮ－（ヒドロキシアルキル）（メタ）アクリルアミド成分が挙げられ、（メタ）アクリルアミド成分が好ましく、アクリルアミド成分がより好ましい。
　一般式（Ｂ－２）で表される構成部分は、１種類でもよく、２種類以上であってもよい。 Specific examples of the components represented by the above general formula (B-2) include (meth)acrylamide component; N-(hydroxyalkyl)(meth) such as N-(2-hydroxyethyl)(meth)acrylamide component; Acrylamide components are mentioned, (meth)acrylamide components are preferred, and acrylamide components are more preferred.
The number of constituent parts represented by general formula (B-2) may be one, or two or more.
　水溶性高分子（Ｘ）は、電極活物質層の体積変化を効果的に抑制してサイクル特性を向上させる観点から、（メタ）アクリルアミド成分を含むことが好ましく、アクリルアミド成分を含むことがより好ましい。 The water-soluble polymer (X) preferably contains a (meth)acrylamide component, and more preferably contains an acrylamide component, from the viewpoint of effectively suppressing the volume change of the electrode active material layer and improving cycle characteristics. .
　本発明に用いられる水溶性高分子（Ｘ）は、本発明の効果を損なわない範囲内で、上記一般式（Ｂ－２）で表される構成成分以外の構成成分（以下、「その他の構成成分」と称す。）を更に含んでもよく、このような構成成分として、下記一般式（Ｂ－１）で表される構成成分、アクリロニトリル成分、Ｎ－ビニル－２－ピロリドン成分及びスチレン成分が挙げられる。
　その他の構成成分としては、アクリロニトリル成分、Ｎ－ビニル－２－ピロリドン成分及びスチレン成分のうちの少なくとも１種を含むことが好ましく、アクリロニトリル成分を含むことがより好ましい。 The water-soluble polymer (X) used in the present invention may contain constituent components other than those represented by the above general formula (B-2) (hereinafter referred to as "other constituents") within a range that does not impair the effects of the present invention. The composition may further include a component represented by the following general formula (B-1), an acrylonitrile component, an N-vinyl-2-pyrrolidone component, and a styrene component. It will be done.
The other components preferably include at least one of an acrylonitrile component, an N-vinyl-2-pyrrolidone component, and a styrene component, and more preferably an acrylonitrile component.
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
　一般式（Ｂ－１）中、Ｒ１１～Ｒ１３は水素原子、シアノ基又は炭素数１～６のアルキル基を示す。この炭素数１～６のアルキル基は直鎖でも分岐を有してもよい。この炭素数１～６のアルキル基は、炭素数１～４のアルキル基が好ましく、メチル又はエチルがより好ましく、メチルが更に好ましい。
　Ｒ１１及びＲ１２としては、水素原子が好ましい。
　Ｒ１３としては、水素原子又はメチルが好ましく、水素原子がより好ましい。
　Ｒ１４は水素原子、ヒドロキシ基、炭素数１～６のアルコキシ基（アルキルオキシ基）、シアノ基、フェニル基、カルボキシ基、スルホ基（－Ｓ（＝Ｏ）２（ＯＨ））、リン酸基（－ＯＰ（＝Ｏ）（ＯＨ）２）又はホスホン酸基（－Ｐ（＝Ｏ）（ＯＨ）２）を示す。上記の炭素数１～６のアルコキシ基中のアルキル基は直鎖でも分岐を有してもよい。この炭素数１～６のアルコキシ基は、炭素数１～４のアルコキシ基が好ましく、メトキシ又はエトキシがより好ましい。
　Ｒ１４としては、水素原子、ヒドロキシ基、メトキシ又はエトキシが好ましく、水素原子がより好ましい。
　Ｌ１１は単結合、炭素数１～１６のアルキレン基、炭素数６～１２のアリーレン基、酸素原子（－Ｏ－）、硫黄原子（－Ｓ－）、カルボニル基（＞Ｃ＝Ｏ）若しくはイミノ基（＞ＮＲＮ’）、又はこれらを組み合わせた連結基を示す。また、Ｌ１１は後述の置換基群Ｔから選ばれる置換基を有していてもよく、この置換基としては、ヒドロキシ基が好ましい。
　上記ＲＮ’は、水素原子、アルキル基を示す。
　Ｌ１１が単結合以外の連結基を示す場合、Ｌ１１の化学式量は１４～２０００が好ましく、１４～５００がより好ましく、２８～２００が更に好ましい。Ｌ１１が有しうる炭素数１～１６のアルキレン基は直鎖でも分岐を有してもよい。このアルキレン基の炭素数は１～１２が好ましく、１～１０がより好ましく、１～６が更に好ましく、１～４が特に好ましい。
　Ｌ１１としては、単結合、メチレン、エチレン、プロピレン、２－ヒドロキシプロピレン及びブチレンが好ましく、単結合、エチレン又はブチレンがより好ましい。
　＊は上記ポリマー（水溶性高分子（Ｘ））主鎖中に組み込まれるための結合部位を示す。 In general formula (B-1), R 11 to R 13 represent a hydrogen atom, a cyano group, or an alkyl group having 1 to 6 carbon atoms. This alkyl group having 1 to 6 carbon atoms may be linear or branched. The alkyl group having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 4 carbon atoms, more preferably methyl or ethyl, and even more preferably methyl.
A hydrogen atom is preferable as R 11 and R 12 .
R 13 is preferably a hydrogen atom or methyl, and more preferably a hydrogen atom.
R14 is a hydrogen atom, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms (alkyloxy group), a cyano group, a phenyl group, a carboxy group, a sulfo group (-S(=O) 2 (OH)), a phosphoric acid group (-OP(=O)(OH) 2 ) or a phosphonic acid group (-P(=O)(OH) 2 ). The alkyl group in the above alkoxy group having 1 to 6 carbon atoms may be linear or branched. The alkoxy group having 1 to 6 carbon atoms is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably methoxy or ethoxy.
R 14 is preferably a hydrogen atom, a hydroxy group, methoxy or ethoxy, and more preferably a hydrogen atom.
L 11 is a single bond, an alkylene group having 1 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom (-O-), a sulfur atom (-S-), a carbonyl group (>C=O), or an imino group. Indicates a group (>NR N ') or a linking group that is a combination of these. Further, L 11 may have a substituent selected from substituent group T described below, and this substituent is preferably a hydroxy group.
The above R N ' represents a hydrogen atom or an alkyl group.
When L 11 represents a linking group other than a single bond, the chemical formula weight of L 11 is preferably from 14 to 2,000, more preferably from 14 to 500, even more preferably from 28 to 200. The alkylene group having 1 to 16 carbon atoms that L 11 may have may be linear or branched. The alkylene group preferably has 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, even more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms.
L 11 is preferably a single bond, methylene, ethylene, propylene, 2-hydroxypropylene, and butylene, and more preferably a single bond, ethylene, or butylene.
* indicates a bonding site for incorporation into the main chain of the above polymer (water-soluble polymer (X)).
　上記一般式（Ｂ－１）で表される構成成分の具体例としては、（メタ）アクリル酸成分；（メタ）アクリル酸メチル成分、（メタ）アクリル酸エチル成分、（メタ）アクリル酸プロピル成分及び（メタ）アクリル酸ブチル成分等の（メタ）アクリル酸アルキル成分；２－ヒドロキシエチル（メタ）アクリレート成分、４－ヒドロキシブチル（メタ）アクリレート成分、２，３－ジヒドロキシプロピル（メタ）アクリレート成分等のヒドロキシアルキル（メタ）アクリレート成分；メトキシエチル（メタ）アクリレート成分、エトキシエチル（メタ）アクリレート成分等のアルコキシアルキル（メタ）アクリレート成分が挙げられ、（メタ）アクリル酸成分、又はヒドロキシアルキル（メタ）アクリレート成分が好ましい。 Specific examples of the components represented by the above general formula (B-1) include (meth)acrylic acid component; methyl (meth)acrylate component, ethyl (meth)acrylate component, and propyl (meth)acrylate component. and alkyl (meth)acrylate components such as butyl (meth)acrylate components; 2-hydroxyethyl (meth)acrylate component, 4-hydroxybutyl (meth)acrylate component, 2,3-dihydroxypropyl (meth)acrylate component, etc. hydroxyalkyl (meth)acrylate component; examples include alkoxyalkyl (meth)acrylate components such as methoxyethyl (meth)acrylate component and ethoxyethyl (meth)acrylate component; Acrylate components are preferred.
　なお、水溶性高分子（Ｘ）に含まれる構成成分の種類の数は特に制限されず、１～１０種が好ましく、１～５種がより好ましく、１～３種が更に好ましく、１種又は２種が特に好ましい。後述する水溶性高分子（Ｘ）の具体例では、構成成分の種類の数が１種、２種又は３種の重合体を記載している。この具体例において、構成成分の種類の数が１種の重合体はポリアクリルアミドである。 The number of constituent components contained in the water-soluble polymer (X) is not particularly limited, and is preferably 1 to 10, more preferably 1 to 5, even more preferably 1 to 3, and one or more. Two types are particularly preferred. In the specific examples of the water-soluble polymer (X) described below, polymers having one, two, or three types of constituent components are described. In this specific example, the polymer having one type of component is polyacrylamide.
　水溶性高分子（Ｘ）中、上記一般式（Ｂ－２）で表される構成成分の含有量は、６０質量％以上が好ましく、７０質量％以上がより好ましく、８０質量％以上がより好ましく、８５質量％以上が更に好ましく、１００質量％であってもよい。
　なお、水溶性高分子（Ｘ）がその他の構成成分を含む場合には、上記一般式（Ｂ－２）で表される構成成分の含有量は、６５質量％以上であることも好ましく、７５質量％以上がより好ましい。
　水溶性高分子（Ｘ）中、水溶性高分子（Ｘ）がその他の構成成分を含む場合において、上記一般式（Ｂ－２）で表される構成成分の含有量を好ましい範囲として示すと、６０～９５質量％が好ましく、６５～９０質量％がより好ましく、７０～９０質量％がより好ましく、７５～９０質量％がより好ましく、８０～９０質量％がより好ましく、８５～９０質量％がより好ましい。
　水溶性高分子（Ｘ）中、水溶性高分子（Ｘ）がその他の構成成分を含む場合には、その他の構成成分の含有量は合計で、５～４０質量％が好ましく、１０～３５質量％がより好ましく、１０～３０質量％がより好ましく、１０～２５質量％がより好ましく、１０～２０質量％がより好ましく、１０～１５質量％がより好ましい。
　水溶性高分子（Ｘ）中、上記一般式（Ｂ－１）で表される構成成分、アクリロニトリル成分、Ｎ－ビニル－２－ピロリドン成分及びスチレン成分の含有量は、合計で、４０質量％以下が好ましく、３０質量％以下がより好ましく、２０質量％以下が更に好ましい。 In the water-soluble polymer (X), the content of the component represented by the above general formula (B-2) is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. , more preferably 85% by mass or more, and may be 100% by mass.
In addition, when the water-soluble polymer (X) contains other components, the content of the components represented by the above general formula (B-2) is preferably 65% by mass or more, and 75% by mass or more. More preferably, the amount is % by mass or more.
In the water-soluble polymer (X), when the water-soluble polymer (X) contains other components, the content of the component represented by the above general formula (B-2) is shown as a preferable range: Preferably 60 to 95% by mass, more preferably 65 to 90% by mass, more preferably 70 to 90% by mass, more preferably 75 to 90% by mass, more preferably 80 to 90% by mass, and more preferably 85 to 90% by mass. More preferred.
In the water-soluble polymer (X), when the water-soluble polymer (X) contains other constituent components, the total content of the other constituent components is preferably 5 to 40% by mass, and 10 to 35% by mass. %, more preferably 10 to 30% by weight, more preferably 10 to 25% by weight, more preferably 10 to 20% by weight, and even more preferably 10 to 15% by weight.
In the water-soluble polymer (X), the total content of the component represented by the above general formula (B-1), acrylonitrile component, N-vinyl-2-pyrrolidone component, and styrene component is 40% by mass or less is preferable, 30% by mass or less is more preferable, and even more preferably 20% by weight or less.
　本発明に用いられる水溶性高分子（Ｘ）の重量平均分子量（Ｍｗ）は特に制限されず、サイクル特性向上の観点から、１０００００～９０００００が好ましく、２０００００～５０００００がより好ましい。
　水溶性高分子（Ｘ）は架橋構造を有しないこと、すなわち、鎖状高分子であることが好ましい。 The weight average molecular weight (Mw) of the water-soluble polymer (X) used in the present invention is not particularly limited, and from the viewpoint of improving cycle characteristics, it is preferably 100,000 to 900,000, more preferably 200,000 to 500,000.
It is preferable that the water-soluble polymer (X) does not have a crosslinked structure, that is, it is a chain polymer.
　また、サイクル特性向上の観点から、水溶性高分子（Ｘ）の分子量分布は、５.０以下が好ましく、３.０以下がより好ましい。一方、分子量分布は１．０以上が実際的である。
　水溶性高分子（Ｘ）の分子量分布は分散度とも称され、［重量平均分子量（Ｍｗ）］／［数平均分子量（Ｍｎ）］により算出される。 Moreover, from the viewpoint of improving cycle characteristics, the molecular weight distribution of the water-soluble polymer (X) is preferably 5.0 or less, more preferably 3.0 or less. On the other hand, it is practical for the molecular weight distribution to be 1.0 or more.
The molecular weight distribution of the water-soluble polymer (X) is also called the degree of dispersion, and is calculated by [weight average molecular weight (Mw)]/[number average molecular weight (Mn)].
－重量平均分子量及び数平均分子量の測定－
　本発明において、ポリマーの重量平均分子量及び数平均分子量については、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）によって測定する。これら重量平均分子量及び数平均分子量における「分子量」は、ポリエチレンオキシド換算の分子量をいう。その測定法としては、基本として下記測定条件１の方法により測定した値とする。ただし、ポリマーの種類によっては適宜適切な溶離液を選定して用いればよい。
（測定条件１）
　　測定器：ＨＬＣ－８２２０ＧＰＣ（商品名、東ソー社製）
　　カラム：ＴＯＳＯＨ　ＴＳＫｇｅｌ　５０００ＰＷＸＬ（商品名、東ソー社製）、ＴＯＳＯＨ　ＴＳＫｇｅｌ　Ｇ４０００ＰＷＸＬ（商品名、東ソー社製）、ＴＯＳＯＨ　ＴＳＫｇｅｌ　Ｇ２５００ＰＷＸＬ（商品名、東ソー社製）をつなげる。
　　キャリア：２００ｍＭ　硝酸ナトリウム水溶液
　　測定温度：４０℃
　　キャリア流量：１．０ｍｌ／ｍｉｎ
　　試料濃度：０．２質量％
　　検出器：ＲＩ（屈折率）検出器
架橋がかかっている場合など、上記測定条件１で分子量が測れない場合は下記測定条件２で静的光散乱により、分子量を測定する。
（測定条件２）
　　測定器：ＤＬＳ－８０００（商品名、大塚電子社製）
　　測定濃度：０．２５、０．５０、０．７５、１．００ｍｇ／ｍＬ
　　希釈液：０．１Ｍ　ＮａＣｌ水溶液
　　レーザー波長：６３３ｎｍ
　　ピンホール：ＰＨ１＝Ｏｐｅｎ、ＰＨ２＝Ｓｌｉｔ
　　測定角度：６０、７０、８０、９０、１００、１１０、１２０、１３０度
　　解析法：Ｚｉｍｍ平方根プロットより、分子量を測定する。解析に必要なｄｎ／ｄｃはＡｂｂｅ屈折率計で実測する。 -Measurement of weight average molecular weight and number average molecular weight-
In the present invention, the weight average molecular weight and number average molecular weight of the polymer are measured by gel permeation chromatography (GPC). The "molecular weight" in these weight average molecular weight and number average molecular weight refers to the molecular weight in terms of polyethylene oxide. As for the measurement method, the values are basically measured according to the method of measurement condition 1 below. However, depending on the type of polymer, an appropriate eluent may be selected and used.
(Measurement conditions 1)
Measuring instrument: HLC-8220GPC (product name, manufactured by Tosoh Corporation)
Column: TOSOH TSKgel 5000PWXL (trade name, manufactured by Tosoh Corporation), TOSOH TSKgel G4000PWXL (trade name, manufactured by Tosoh Corporation), and TOSOH TSKgel G2500PWXL (trade name, manufactured by Tosoh Corporation) are connected.
Carrier: 200mM sodium nitrate aqueous solution Measurement temperature: 40°C
Carrier flow rate: 1.0ml/min
Sample concentration: 0.2% by mass
Detector: RI (refractive index) detector If the molecular weight cannot be measured under measurement condition 1 above, such as when crosslinking occurs, the molecular weight is measured by static light scattering under measurement condition 2 below.
(Measurement conditions 2)
Measuring instrument: DLS-8000 (product name, manufactured by Otsuka Electronics)
Measured concentration: 0.25, 0.50, 0.75, 1.00mg/mL
Diluent: 0.1M NaCl aqueous solution Laser wavelength: 633nm
Pinhole: PH1=Open, PH2=Slit
Measurement angle: 60, 70, 80, 90, 100, 110, 120, 130 degrees Analysis method: Measure molecular weight from Zimm square root plot. The dn/dc required for analysis is actually measured using an Abbe refractometer.
　本発明に用いられる水溶性高分子（Ｘ）は、電極活物質層の体積変化を効果的に抑制してサイクル特性を向上させる観点から、引張弾性率が３５００ＭＰａ以上であることが好ましく、４０００ＭＰａ以上がより好ましく、５０００ＭＰａ以上が更に好ましく、６０００ＭＰａ以上が特に好ましい。一方、引張弾性率は１５０００ＭＰａ以下が実際的である。水溶性高分子（Ｘ）の引張弾性率は、３５００～１５０００ＭＰａであることが好ましく、４０００～１５０００ＭＰａであることがより好ましく、５０００～１５０００ＭＰａであることがより好ましく、６０００～１５０００ＭＰａであることがより好ましい。
　本発明において、上記引張弾性率は、後述する実施例に記載の本発明のバインダー組成物の引張弾性率試験において、本発明のバインダー組成物に代えて水溶性高分子（Ｘ）の水溶液を用いること以外は、上記本発明のバインダー組成物の引張弾性率試験と同様の方法により得られる値とする。 The water-soluble polymer (X) used in the present invention preferably has a tensile modulus of 3500 MPa or more, preferably 4000 MPa or more, from the viewpoint of effectively suppressing the volume change of the electrode active material layer and improving cycle characteristics. is more preferable, 5000 MPa or more is still more preferable, and 6000 MPa or more is particularly preferable. On the other hand, it is practical for the tensile modulus to be 15,000 MPa or less. The tensile modulus of the water-soluble polymer (X) is preferably 3,500 to 15,000 MPa, more preferably 4,000 to 15,000 MPa, more preferably 5,000 to 15,000 MPa, and more preferably 6,000 to 15,000 MPa. preferable.
In the present invention, the above tensile modulus is determined by using an aqueous solution of water-soluble polymer (X) in place of the binder composition of the present invention in a tensile modulus test of the binder composition of the present invention described in the Examples described below. Other than this, the value is obtained by the same method as the tensile modulus test of the binder composition of the present invention described above.
　上記水溶性高分子（Ｘ）は、上述した各構造ないし部分構造において更に置換基を有していてもよく、この置換基としては、下記置換基群Ｔから選ばれる置換基が挙げられる。 The water-soluble polymer (X) may further have a substituent in each structure or partial structure described above, and examples of the substituent include substituents selected from the substituent group T below.
－　置換基群Ｔ　－
　アルキル基（好ましくは炭素数が１～２０であるアルキル基、例えばメチル、エチル、イソプロピル、ｔ－ブチル、ペンチル、ヘプチル、１－エチルペンチル、ベンジル、２－エトキシエチル、１－カルボキシメチル等）、アルケニル基（好ましくは炭素数が２～２０であるアルケニル基、例えば、ビニル、アリル、オレイル等）、アルキニル基（好ましくは炭素数が２～２０であるアルキニル基、例えば、エチニル、ブタジイニル、フェニルエチニル等）、シクロアルキル基（好ましくは炭素数が３～２０であるシクロアルキル基、例えば、シクロプロピル、シクロペンチル、シクロヘキシル、４－メチルシクロヘキシル等）、アリール基（好ましくは炭素数が６～２６であるアリール基、例えば、フェニル、１－ナフチル、４－メトキシフェニル、２－クロロフェニル、３－メチルフェニル等）、ヘテロ環基（好ましくは炭素数が２～２０であるヘテロ環基で、より好ましくは、酸素原子、硫黄原子及び窒素原子の少なくとも１種を環構成原子として有する５又は６員のヘテロ環基である。ヘテロ環基は芳香族ヘテロ環基及び脂肪族ヘテロ環基を含む。例えば、テトラヒドロピラン環基、テトラヒドロフラン環基、２－ピリジル、４－ピリジル、２－イミダゾリル、２－ベンゾイミダゾリル、２－チアゾリル、２－オキサゾリル等）、アルコキシ基（好ましくは炭素数が１～２０であるアルコキシ基、例えば、メトキシ、エトキシ、イソプロピルオキシ、ベンジルオキシ等）、アリールオキシ基（好ましくは炭素数が６～２６であるアリールオキシ基、例えば、フェノキシ、１－ナフチルオキシ、３－メチルフェノキシ、４－メトキシフェノキシ等）、ヘテロ環オキシ基（上記ヘテロ環基に－Ｏ－基が結合した基）、アルコキシカルボニル基（好ましくは炭素数が２～２０であるアルコキシカルボニル基、例えば、エトキシカルボニル、２－エチルヘキシルオキシカルボニル等）、アリールオキシカルボニル基（好ましくは炭素数が７～２６であるアリールオキシカルボニル基、例えば、フェノキシカルボニル、１－ナフチルオキシカルボニル、３－メチルフェノキシカルボニル、４－メトキシフェノキシカルボニル等）、アミノ基（好ましくは炭素数が０～２０であるアミノ基であり、アルキル基及びアリール基から選択される基で置換されたアミノ基を含む。例えば、アミノ（－ＮＨ２）、Ｎ，Ｎ－ジメチルアミノ、Ｎ，Ｎ－ジエチルアミノ、Ｎ－エチルアミノ、アニリノ等）、スルファモイル基（好ましくは炭素数が０～２０であるスルファモイル基であり、アルキル基及びアリール基から選択される基で置換されたスルファモイル基を含む。例えば、スルファモイル（－ＳＯ２ＮＨ２）、Ｎ，Ｎ－ジメチルスルファモイル、Ｎ－フェニルスルファモイル等）、アシル基（アルキルカルボニル基、アルケニルカルボニル基、アルキニルカルボニル基、アリールカルボニル基及びヘテロ環カルボニル基を含み、好ましくは炭素数が１～２０であるアシル基、例えば、ホルミル、アセチル、プロピオニル、ブチリル、オクタノイル、ヘキサデカノイル、アクリロイル、メタクリロイル、クロトノイル、ベンゾイル、ナフトイル、ニコチノイル等）、アシルオキシ基（アルキルカルボニルオキシ基、アルケニルカルボニルオキシ基、アルキニルカルボニルオキシ基、アリールカルボニルオキシ基及びヘテロ環カルボニルオキシ基を含み、好ましくは炭素数が１～２０であるアシルオキシ基、例えば、ホルミルオキシ、アセチルオキシ、プロピオニルオキシ、ブチリルオキシ、オクタノイルオキシ、ヘキサデカノイルオキシ、アクリロイルオキシ、メタクリロイルオキシ、クロトノイルオキシ、ベンゾイルオキシ、ナフトイルオキシ、ニコチノイルオキシ等）、カルバモイル基（好ましくは炭素数が１～２０であるカルバモイル基であり、アルキル基及びアリール基から選択される基で置換されたカルバモイル基を含む。例えば、Ｎ，Ｎ－ジメチルカルバモイル、Ｎ－フェニルカルバモイル等）、アシルアミノ基（好ましくは炭素数が１～２０であるアシルアミノ基であり、アシルアミノ基におけるアシル基としては、上記アシル基が好ましく挙げられる。例えば、アセチルアミノ、ベンゾイルアミノ等）、アルキルチオ基（好ましくは炭素数が１～２０であるアルキルチオ基、例えば、メチルチオ、エチルチオ、イソプロピルチオ、ベンジルチオ等）、アリールチオ基（好ましくは炭素数が６～２６であるアリールチオ基、例えば、フェニルチオ、１－ナフチルチオ、３－メチルフェニルチオ、４－メトキシフェニルチオ等）、アリールシリル基（好ましくは炭素数が６～４２であるアリールシリル基、例えば、トリフェニルシリル等）、ヘテロ環チオ基（上記ヘテロ環基に－Ｓ－基が結合した基）、アルキルスルホニル基（好ましくは炭素数が１～２０であるアルキルスルホニル基、例えば、メチルスルホニル、エチルスルホニル等）、アリールスルホニル基（好ましくは炭素数が６～２２であるアリールスルホニル基、例えば、ベンゼンスルホニル等）、アルキルシリル基（好ましくは炭素数が１～２０であるアルキルシリル基、例えば、モノメチルシリル、ジメチルシリル、トリメチルシリル、トリエチルシリル等）、亜リン酸基（好ましくは炭素数が０～２０である亜リン酸基、例えば、－ＯＰ（＝Ｏ）（－ＯＨ）（ＲＰ））、次亜リン酸基（好ましくは炭素数が０～２０である次亜リン酸基、例えば、－ＯＰ（＝Ｏ）（ＲＰ）２）、ホスホリル基（好ましくは炭素数が０～２０であるホスホリル基、例えば、－Ｐ（＝Ｏ）（ＲＰ）２）、ホスフィニル基（好ましくは炭素数が０～２０であるホスフィニル基、例えば、－Ｐ（ＲＰ）２）、スルホ基、リン酸基、ホスホン酸基、カルボキシ基、ヒドロキシ基、スルファニル基、シアノ基、ハロゲン原子（例えばフッ素原子、塩素原子、臭素原子、ヨウ素原子）が挙げられる。ＲＰは、水素原子又は置換基（好ましくは置換基群Ｔから選択される基）である。
　また、これらの置換基群Ｔで挙げた各基は、上記置換基群Ｔで挙げた各基を更に置換基として有していてもよい。 - Substituent group T -
Alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, such as methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), Alkenyl group (preferably an alkenyl group having 2 to 20 carbon atoms, such as vinyl, allyl, oleyl, etc.), alkynyl group (preferably an alkynyl group having 2 to 20 carbon atoms, such as ethynyl, butadiynyl, phenylethynyl) etc.), cycloalkyl groups (preferably cycloalkyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.), aryl groups (preferably having 6 to 26 carbon atoms) Aryl groups (for example, phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, etc.), heterocyclic groups (preferably heterocyclic groups having 2 to 20 carbon atoms, more preferably, A 5- or 6-membered heterocyclic group having at least one of an oxygen atom, a sulfur atom, and a nitrogen atom as a ring constituent atom.Heterocyclic groups include aromatic heterocyclic groups and aliphatic heterocyclic groups.For example, tetrahydro pyran ring group, tetrahydrofuran ring group, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, etc.), alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, For example, methoxy, ethoxy, isopropyloxy, benzyloxy, etc.), aryloxy groups (preferably aryloxy groups having 6 to 26 carbon atoms, such as phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy) etc.), heterocyclic oxy groups (groups in which -O- group is bonded to the above heterocyclic group), alkoxycarbonyl groups (preferably alkoxycarbonyl groups having 2 to 20 carbon atoms, such as ethoxycarbonyl, 2-ethylhexyloxy carbonyl, etc.), aryloxycarbonyl group (preferably an aryloxycarbonyl group having 7 to 26 carbon atoms, such as phenoxycarbonyl, 1-naphthyloxycarbonyl, 3-methylphenoxycarbonyl, 4-methoxyphenoxycarbonyl, etc.), amino group (preferably an amino group having 0 to 20 carbon atoms, including an amino group substituted with a group selected from an alkyl group and an aryl group. For example, amino (-NH 2 ), N,N-dimethyl amino, N,N-diethylamino, N-ethylamino, anilino, etc.), sulfamoyl group (preferably a sulfamoyl group having 0 to 20 carbon atoms, substituted with a group selected from alkyl groups and aryl groups) Contains groups. For example, sulfamoyl (-SO 2 NH 2 ), N,N-dimethylsulfamoyl, N-phenylsulfamoyl, etc.), acyl groups (alkylcarbonyl group, alkenylcarbonyl group, alkynylcarbonyl group, arylcarbonyl group, and heterocycle) Acyl group containing a carbonyl group and preferably having 1 to 20 carbon atoms, such as formyl, acetyl, propionyl, butyryl, octanoyl, hexadecanoyl, acryloyl, methacryloyl, crotonoyl, benzoyl, naphthoyl, nicotinoyl, etc.), acyloxy group (Including alkylcarbonyloxy groups, alkenylcarbonyloxy groups, alkynylcarbonyloxy groups, arylcarbonyloxy groups and heterocyclic carbonyloxy groups, preferably acyloxy groups having 1 to 20 carbon atoms, such as formyloxy, acetyloxy, propionyloxy, butyryloxy, octanoyloxy, hexadecanoyloxy, acryloyloxy, methacryloyloxy, crotonoyloxy, benzoyloxy, naphthoyloxy, nicotinoyloxy, etc.), carbamoyl group (preferably has 1 to 20 carbon atoms) It is a carbamoyl group, and includes a carbamoyl group substituted with a group selected from an alkyl group and an aryl group.For example, N,N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.), an acylamino group (preferably having 1 to 1 carbon atoms), and a carbamoyl group substituted with a group selected from alkyl groups and aryl groups. 20, and the acyl group in the acylamino group is preferably the above-mentioned acyl group.For example, acetylamino, benzoylamino, etc.), an alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms, For example, methylthio, ethylthio, isopropylthio, benzylthio, etc.), arylthio group (preferably an arylthio group having 6 to 26 carbon atoms, such as phenylthio, 1-naphthylthio, 3-methylphenylthio, 4-methoxyphenylthio, etc.) , an arylsilyl group (preferably an arylsilyl group having 6 to 42 carbon atoms, such as triphenylsilyl), a heterocyclic thio group (a group in which an -S- group is bonded to the above heterocyclic group), an alkylsulfonyl group (preferably an alkylsulfonyl group having 1 to 20 carbon atoms, such as methylsulfonyl, ethylsulfonyl, etc.), an arylsulfonyl group (preferably an arylsulfonyl group having 6 to 22 carbon atoms, such as benzenesulfonyl), Alkylsilyl group (preferably alkylsilyl group having 1 to 20 carbon atoms, such as monomethylsilyl, dimethylsilyl, trimethylsilyl, triethylsilyl, etc.), phosphorous group (preferably phosphorous group having 0 to 20 carbon atoms) Acid groups, such as -OP(=O)(-OH)(R P )), hypophosphorous acid groups (preferably hypophosphorous acid groups having 0 to 20 carbon atoms, such as -OP(=O )(R P ) 2 ), phosphoryl group (preferably a phosphoryl group having 0 to 20 carbon atoms, such as -P(=O)(R P ) 2 ), phosphinyl group (preferably having 0 to 20 carbon atoms) A phosphinyl group, such as -P(R P ) 2 ), a sulfo group, a phosphoric acid group, a phosphonic acid group, a carboxy group, a hydroxy group, a sulfanyl group, a cyano group, a halogen atom (such as a fluorine atom, a chlorine atom, a bromine atom) atoms, iodine atoms). R P is a hydrogen atom or a substituent (preferably a group selected from substituent group T).
Moreover, each group listed in these substituent group T may further have each group listed in the above-mentioned substituent group T as a substituent.
　本発明に用いられる水溶性高分子（Ｘ）は、通常のポリマーの合成方法により得ることができる。本発明に用いられる水溶性高分子（Ｘ）の合成において、連鎖重合等の方法及び条件は、特に限定されず、通常の方法及び条件を、目的に応じて適宜に適用することができる。
　なお、水溶性高分子（Ｘ）の「水溶性」は、例えば、構成成分の種類及びその含有量によって制御することができる。 The water-soluble polymer (X) used in the present invention can be obtained by a conventional polymer synthesis method. In the synthesis of the water-soluble polymer (X) used in the present invention, the methods and conditions for chain polymerization etc. are not particularly limited, and conventional methods and conditions can be appropriately applied depending on the purpose.
Note that the "water solubility" of the water-soluble polymer (X) can be controlled, for example, by the types of constituent components and their contents.
　本発明に用いる水溶性高分子（Ｘ）の好ましい具体例を以下に示すが、本発明はこれらに限定して解釈されるものではない。下記具体例において、ａ、ｂ及びｃは各構成成分の割合（質量％）を示す。ａ＝９９～６０であり、ｂ＝１～４０であり、ｃ＝１～４０である。ただし、ａ＋ｂ＋ｃ＝１００であり、ｂ＋ｃ＝１～４０である。 Preferred specific examples of the water-soluble polymer (X) used in the present invention are shown below, but the present invention is not to be interpreted as being limited to these. In the specific examples below, a, b, and c indicate the proportions (% by mass) of each component. a=99-60, b=1-40, and c=1-40. However, a+b+c=100, and b+c=1 to 40.
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000005
　本発明において、水溶性高分子（Ｘ）は１種単独で用いてもよく、２種以上を組み合わせて用いてもよい。 In the present invention, the water-soluble polymer (X) may be used alone or in combination of two or more.
（水溶性化合物（Ｙ））
　本発明において、水溶性化合物（Ｙ）は、上述の水溶性高分子（Ｘ）とは構造の異なる水溶性の化合物（単量体または高分子体）であり、二次電池の電極活物質層形成用スラリーの増粘剤として機能するものを広く用いることができる。上記増粘剤として例えば、セルロース化合物及び天然多糖類等の多糖類が挙げられる。
　セルロース化合物としては、例えばメチルセルロース、エチルセルロース、ベンジルセルロース、トリエチルセルロース、シアノエチルセルロース、ニトロセルロース、ヒドロキシメチルセルロース、ヒドロキシエチルセルロース（ＨＥＣ）、ヒドロキシプロピルセルロース（ＨＰＣ）、ヒドロキシプロピルメチルセルロース（ＨＰＭＣ）、ヒドロキシブチルメチルセルロース、カルボキシメチルセルロース（ＣＭＣ）、アミノメチルヒドロキシプロピルセルロース、アミノエチルヒドロキシプロピルセルロース、セルロースナノファイバー（ＣＮＦ）、セルロースナノクリスタル（ＣＮＣ）等が挙げられる。また、セルロース化合物は、アンモニウム塩、ナトリウム塩、リチウム塩等の塩の態様であってもよい。
　天然多糖類としては、例えばカラギナン、キサンタンガム、グァーガム、タマリンドガム（タマリンドシードガム）、ダイユータンガム、ウェランガム、ジェランガム、ローカストビーンガム、タラガム等が挙げられる。
　これらの中でも、水溶性化合物（Ｙ）は、カルボキシメチルセルロース、セルロースナノファイバー、ヒドロキシエチルセルロース、ヒドロキシプロピルセルロース及びキサンタンガムの少なくとも１種を含むことが好ましい。
　本発明において、水溶性化合物（Ｙ）は１種単独で用いてもよく、２種以上を組み合わせて用いてもよい。 (Water-soluble compound (Y))
In the present invention, the water-soluble compound (Y) is a water-soluble compound (monomer or polymer) having a different structure from the water-soluble polymer (X) described above, and is A wide variety of agents that function as thickeners for forming slurries can be used. Examples of the thickener include cellulose compounds and polysaccharides such as natural polysaccharides.
Examples of cellulose compounds include methylcellulose, ethylcellulose, benzylcellulose, triethylcellulose, cyanoethylcellulose, nitrocellulose, hydroxymethylcellulose, hydroxyethylcellulose (HEC), hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC), hydroxybutylmethylcellulose, carboxy Examples include methylcellulose (CMC), aminomethylhydroxypropylcellulose, aminoethylhydroxypropylcellulose, cellulose nanofiber (CNF), and cellulose nanocrystal (CNC). Further, the cellulose compound may be in the form of a salt such as an ammonium salt, a sodium salt, or a lithium salt.
Examples of natural polysaccharides include carrageenan, xanthan gum, guar gum, tamarind gum (tamarind seed gum), diutan gum, welan gum, gellan gum, locust bean gum, and tara gum.
Among these, the water-soluble compound (Y) preferably contains at least one of carboxymethyl cellulose, cellulose nanofibers, hydroxyethyl cellulose, hydroxypropyl cellulose, and xanthan gum.
In the present invention, the water-soluble compound (Y) may be used alone or in combination of two or more.
（重合体粒子）
　本発明に用いられる重合体粒子は粒子状のポリマーであり、「粒子状」は、偏平状、無定形等であってもよく、球状若しくは顆粒状が好ましい。
　なお、重合体粒子は非水溶性高分子である。すなわち、重合体粒子は２０℃において水に対する溶解度が１０ｇ／Ｌ－Ｈ２Ｏ未満である（水１リットルに対して１０ｇ以上溶解しない）ポリマーである。 (polymer particles)
The polymer particles used in the present invention are particulate polymers, and "particulate" may be flat, amorphous, etc., and preferably spherical or granular.
Note that the polymer particles are water-insoluble polymers. That is, the polymer particles are polymers whose solubility in water at 20° C. is less than 10 g/L-H 2 O (not more than 10 g per 1 liter of water).
　重合体粒子の引張弾性率は、特に制限されず、固体粒子同士又は集電体と固体粒子との密着性を高めて電極シートの密着性及びサイクル特性を向上させる観点から、１００～３０００ＭＰａが好ましく、１００～１０００ＭＰａがより好ましい。本発明において、上記引張弾性率は、後述する実施例に記載の本発明のバインダー組成物の引張弾性率試験において、本発明のバインダー組成物に代えて重合体粒子（ラテックスポリマー）を用いること以外は、上記本発明のバインダー組成物の引張弾性率試験と同様の方法により得られる値とする。 The tensile modulus of the polymer particles is not particularly limited, and is preferably 100 to 3000 MPa from the viewpoint of improving the adhesion between solid particles or between a current collector and solid particles to improve the adhesion and cycle characteristics of the electrode sheet. , 100 to 1000 MPa is more preferable. In the present invention, the above-mentioned tensile modulus is determined by using polymer particles (latex polymer) in place of the binder composition of the present invention in the tensile modulus test of the binder composition of the present invention described in the Examples described below. is a value obtained by the same method as the tensile modulus test of the binder composition of the present invention described above.
　重合体粒子のガラス転移温度は特に制限されず、電極シートの密着性及びサイクル特性向上の観点から、－５０～１５０℃が好ましく、－３０～１００℃がより好ましい。
　なお、重合体粒子がガラス転移温度を２点以上有する場合には、その全てが上記好ましい範囲内に入ることが好ましい。 The glass transition temperature of the polymer particles is not particularly limited, and from the viewpoint of improving the adhesion and cycle characteristics of the electrode sheet, it is preferably -50 to 150°C, more preferably -30 to 100°C.
In addition, when a polymer particle has two or more glass transition temperatures, it is preferable that all of them fall within the above-mentioned preferable range.
―ガラス転移温度―
　市販品の重合体粒子を用いる場合、重合体粒子のガラス転移温度は製造元のカタログ記載の値を採用する。
　製造元のガラス転移温度の情報が入手できない場合又は合成した重合体粒子を用いる場合は、文献ＰＯＬＹＭＥＲ　ＨＡＮＤＢＯＯＫ　４ｔｈ、３６章の表のガラス転移温度を採用する。上記文献にガラス転移温度が記載されていない場合は下記測定条件で測定して得られるガラス転移温度を採用する。 -Glass-transition temperature-
When using commercially available polymer particles, the glass transition temperature of the polymer particles is the value listed in the manufacturer's catalog.
When information on the glass transition temperature of the manufacturer is not available or when synthesized polymer particles are used, the glass transition temperature in the table in Chapter 36 of the literature POLYMER HANDBOOK 4th is adopted. If the glass transition temperature is not described in the above literature, the glass transition temperature obtained by measurement under the following measurement conditions is employed.
　ガラス転移温度（Ｔｇ）は、重合体粒子の乾燥試料を用いて、示差走査熱量計：Ｘ－ＤＳＣ７０００（商品名、ＳＩＩ・ナノテクノロジー社製）を用いて下記測定条件で測定のうえ算出する。測定は同一の試料で二回実施し、二回目の測定結果を採用する。
（測定条件）
　　測定室内の雰囲気：窒素ガス（５０ｍＬ／ｍｉｎ）
　　昇温速度：５℃／ｍｉｎ
　　測定開始温度：－８０℃
　　測定終了温度：２５０℃
　　試料パン：アルミニウム製パン
　　測定試料の質量：５ｍｇ
　　Ｔｇの算出：ＤＳＣ（示差走査熱量測定）チャートの下降開始点と下降終了点の中間温度の小数点以下を四捨五入することでＴｇを算出する。 The glass transition temperature (Tg) is calculated by measuring a dry sample of polymer particles using a differential scanning calorimeter: X-DSC7000 (trade name, manufactured by SII Nano Technology Co., Ltd.) under the following measurement conditions. Measurements are performed twice on the same sample, and the results of the second measurement are used.
(Measurement condition)
Atmosphere in the measurement chamber: Nitrogen gas (50mL/min)
Temperature increase rate: 5℃/min
Measurement start temperature: -80℃
Measurement end temperature: 250℃
Sample pan: Aluminum pan Mass of measurement sample: 5 mg
Calculation of Tg: Tg is calculated by rounding off the decimal point of the intermediate temperature between the start point and end point of the drop on the DSC (differential scanning calorimetry) chart.
　重合体粒子の平均粒径（平均一次粒子径）は、特に制限されず、５０～３００ｎｍが好ましく、５０～２５０ｎｍがより好ましく、５０～２００ｎｍが更に好ましい。
　市販品の重合体粒子を用いる場合、重合体粒子の平均粒径は製造元のカタログ記載の値を採用する。
　製造元の平均粒径の情報が入手できない場合又は合成した重合体粒子を用いる場合は、重合体粒子の平均粒径は、後述する負極活物質の平均粒径（水中での体積基準のメジアン径Ｄ５０）の測定方法を適用して得られた値を採用すればよい。 The average particle size (average primary particle size) of the polymer particles is not particularly limited, and is preferably from 50 to 300 nm, more preferably from 50 to 250 nm, even more preferably from 50 to 200 nm.
When using commercially available polymer particles, the average particle diameter of the polymer particles is the value listed in the manufacturer's catalog.
When information on the average particle size from the manufacturer is not available or when using synthesized polymer particles, the average particle size of the polymer particles is the average particle size of the negative electrode active material (volume-based median diameter D50 in water) of the negative electrode active material described below. ) may be used.
　重合体粒子は逐次重合ポリマー粒子及び連鎖重合ポリマー粒子のいずれでもよく、連鎖重合ポリマー粒子が好ましい。連鎖重合ポリマー粒子は、ホモポリマーでもよく、コポリマーでもよい。コポリマーの重合形態はランダム及びブロックのいずれでもよい。
　重合体粒子（連鎖重合ポリマー）の構成成分としては、例えば、共役ジエン成分、芳香族ビニルモノマー成分、エチレン性不飽和カルボン酸成分、シアノ基含有エチレン性モノマー成分、エチレン性不飽和カルボン酸エステル成分及びフッ化ビニルモノマー成分が挙げられ、共役ジエン成分、エチレン性不飽和カルボン酸成分、シアノ基含有エチレン性モノマー成分及び芳香族ビニルモノマー成分の少なくとも１種を含むことが好ましい。重合体粒子は、上記構成成分の中でも共役ジエン成分及び芳香族ビニルモノマー成分を有することが好ましい。
　上記において、芳香族ビニルモノマー成分とは、炭素－炭素二重結合（好ましくは１つ又は２つ、より好ましくは１つ）とアリール基（好ましくは１つ）とを有するモノマー由来の成分を意味し、エチレン性不飽和カルボン酸成分とは、炭素－炭素二重結合（好ましくは１つ）とカルボキシ基（好ましくは１つ又は２つ）とを有するモノマー由来の成分を意味し、シアノ基含有エチレン性モノマー成分とは、炭素－炭素二重結合（好ましくは１つ）とシアノ基（好ましくは１つ又は２つ、より好ましくは１つ）とを有するモノマー由来の成分を意味し、エチレン性不飽和カルボン酸エステル成分とは、炭素－炭素二重結合（好ましくは１つ）とカルボン酸エステル部位（エステル化されたカルボキシ基）（好ましくは１つ）とを有するモノマー由来の成分を意味し、フッ化ビニルモノマー成分とは、１～４個（好ましくは２個）のフッ素原子を有するエチレン由来の成分を意味する。
　なお、上記「炭素－炭素二重結合」には、芳香族環の炭素－炭素二重結合は含まれない。 The polymer particles may be either sequential polymer particles or chain polymer particles, and chain polymer particles are preferred. The chain polymer particles may be homopolymers or copolymers. The polymerization form of the copolymer may be either random or block.
Constituent components of the polymer particles (chain polymerization polymer) include, for example, a conjugated diene component, an aromatic vinyl monomer component, an ethylenically unsaturated carboxylic acid component, a cyano group-containing ethylenic monomer component, and an ethylenically unsaturated carboxylic acid ester component. and a fluorinated vinyl monomer component, and preferably contains at least one of a conjugated diene component, an ethylenically unsaturated carboxylic acid component, a cyano group-containing ethylenic monomer component, and an aromatic vinyl monomer component. It is preferable that the polymer particles have a conjugated diene component and an aromatic vinyl monomer component among the above components.
In the above, the aromatic vinyl monomer component means a component derived from a monomer having a carbon-carbon double bond (preferably one or two, more preferably one) and an aryl group (preferably one). However, the ethylenically unsaturated carboxylic acid component means a component derived from a monomer having a carbon-carbon double bond (preferably one) and a carboxy group (preferably one or two), and contains a cyano group. The ethylenic monomer component means a component derived from a monomer having a carbon-carbon double bond (preferably one) and a cyano group (preferably one or two, more preferably one); The unsaturated carboxylic acid ester component means a component derived from a monomer having a carbon-carbon double bond (preferably one) and a carboxylic acid ester moiety (esterified carboxy group) (preferably one). The fluorinated vinyl monomer component means an ethylene-derived component having 1 to 4 (preferably 2) fluorine atoms.
Note that the above-mentioned "carbon-carbon double bond" does not include the carbon-carbon double bond of an aromatic ring.
　共役ジエン成分を導く共役ジエンとしては、例えば、１，３－ブタジエン、２－メチル－１，３－ブタジエン（イソプレン）、２，３－ジメチル－１，３－ブタジエン及び２－クロロ－１，３－ブタジエン等の脂肪族共役ジエンが挙げられる。
　芳香族ビニルモノマー成分を導く芳香族ビニルモノマーとしては、例えば、スチレン、α－メチルスチレン、４－ｔｅｒｔ－ブチルスチレン、４－ｔｅｒｔ－ブトキシスチレン、ビニルトルエン（３－ビニルトルエン、４－ビニルトルエン）及びジビニルベンゼン（ｍ－ジビニルベンゼン、ｐ－ジビニルベンゼン）が挙げられる。
　エチレン性不飽和カルボン酸成分を導くエチレン性不飽和カルボン酸としては、例えば、（メタ）アクリル酸、マレイン酸、イタコン酸及びフマル酸が挙げられる。
　シアノ基含有エチレン性モノマー成分を導くシアノ基含有エチレン性モノマーとしては、例えば、（メタ）アクリロニトリル、α－クロロアクリロニトリル、α－エチルアクリロニトリル及びシアン化ビニリデンが挙げられる。
　エチレン性不飽和カルボン酸エステル成分を導くエチレン性不飽和カルボン酸エステルとしては、例えば、（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸プロピル、（メタ）アクリル酸ブチル、（メタ）アクリル酸ヘキシル、（メタ）アクリル酸オクチル及び２－エチルヘキシル（メタ）アクリレート等の（メタ）アクリル酸アルキルエステルが挙げられる。
　フッ化ビニルモノマー成分を導くフッ化ビニルモノマーとしては、例えば、フッ化ビニリデンが挙げられる。 Examples of the conjugated diene leading to the conjugated diene component include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, and 2-chloro-1,3 - Aliphatic conjugated dienes such as butadiene.
Examples of the aromatic vinyl monomer leading to the aromatic vinyl monomer component include styrene, α-methylstyrene, 4-tert-butylstyrene, 4-tert-butoxystyrene, and vinyltoluene (3-vinyltoluene, 4-vinyltoluene). and divinylbenzene (m-divinylbenzene, p-divinylbenzene).
Examples of the ethylenically unsaturated carboxylic acid leading to the ethylenically unsaturated carboxylic acid component include (meth)acrylic acid, maleic acid, itaconic acid, and fumaric acid.
Examples of the cyano group-containing ethylenic monomer leading to the cyano group-containing ethylenic monomer component include (meth)acrylonitrile, α-chloroacrylonitrile, α-ethyl acrylonitrile, and vinylidene cyanide.
Examples of the ethylenically unsaturated carboxylic ester that leads to the ethylenically unsaturated carboxylic ester component include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, Examples include alkyl (meth)acrylates such as hexyl (meth)acrylate, octyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.
Examples of the vinyl fluoride monomer leading to the vinyl fluoride monomer component include vinylidene fluoride.
　本発明に用いられる重合体粒子は、通常のポリマーの合成方法により得ることができる。本発明に用いられる重合体粒子の合成において、連鎖重合等の方法及び条件は、特に限定されず、通常の方法及び条件を、目的に応じて適宜に適用することができる。
　また、重合体粒子は、上述の逐次重合ポリマー粒子及び連鎖重合ポリマー粒子について、カルボキシ変性等の変性処理を行った粒子でもよい。変性処理の方法及び条件は、特に限定されず、常法により行うことができる。
　重合体粒子の水に対する溶解度、引張弾性率、ガラス転移温度及び平均粒径は、例えば、ポリマー中の構成成分の種類及び含有量により調整できる。 The polymer particles used in the present invention can be obtained by conventional polymer synthesis methods. In the synthesis of the polymer particles used in the present invention, the methods and conditions for chain polymerization etc. are not particularly limited, and conventional methods and conditions can be appropriately applied depending on the purpose.
Further, the polymer particles may be particles obtained by performing a modification treatment such as carboxy modification on the above-mentioned sequential polymer particles and chain polymer particles. The method and conditions for the modification treatment are not particularly limited, and can be carried out by conventional methods.
The water solubility, tensile modulus, glass transition temperature, and average particle size of the polymer particles can be adjusted, for example, by adjusting the types and contents of the constituent components in the polymer.
　重合体粒子の具体例としては、スチレン／ブタジエンコポリマー、アクリルポリマー及びポリ（フッ化ビニリデン）が挙げられ、スチレン／ブタジエンコポリマーが好ましい。
　スチレン／ブタジエンコポリマーとは、上記芳香族ビニルモノマー成分及び上記共役ジエン成分を有する共重合体を意味し、カルボキシ変性等の変性共重合体であってもよい。
　本発明において、重合体粒子は１種単独で用いてもよく、２種以上を組み合わせて用いてもよい。 Specific examples of polymer particles include styrene/butadiene copolymers, acrylic polymers, and poly(vinylidene fluoride), with styrene/butadiene copolymers being preferred.
The styrene/butadiene copolymer means a copolymer having the above-mentioned aromatic vinyl monomer component and the above-mentioned conjugated diene component, and may be a modified copolymer such as a carboxy-modified copolymer.
In the present invention, one type of polymer particles may be used alone, or two or more types may be used in combination.
　本発明のバインダー組成物は、水溶性高分子（Ｘ）、水溶性化合物（Ｙ）及び重合体粒子以外に、電池用のバインダーとして常用されるその他のポリマーを含有していてもよい。
　本発明のバインダー組成物に含有される全ての固形分に占める水溶性高分子（Ｘ）、水溶性化合物（Ｙ）及び重合体粒子の割合は、合計で８０質量％以上が好ましく、９０質量％以上がより好ましく、９５質量％以上が更に好ましく、９９質量％以上が特に好ましい。また、本発明のバインダー組成物に含有される固形分の全てが水溶性高分子（Ｘ）、水溶性化合物（Ｙ）及び重合体粒子であることが最も好ましい。
　本発明のバインダー組成物中、水溶性高分子（Ｘ）と、水溶性化合物（Ｙ）と、重合体粒子との質量比（水溶性高分子（Ｘ）の質量：水溶性化合物（Ｙ）の質量：重合体粒子の質量）は特に制限されず、１０～８０：３～８０：１０～７７が好ましく、２０～７０：３～５０：２０～６０がより好ましい。 In addition to the water-soluble polymer (X), the water-soluble compound (Y), and the polymer particles, the binder composition of the present invention may contain other polymers commonly used as binders for batteries.
The total proportion of the water-soluble polymer (X), the water-soluble compound (Y), and the polymer particles in all the solid content contained in the binder composition of the present invention is preferably 80% by mass or more, and 90% by mass. The content is more preferably 95% by mass or more, even more preferably 99% by mass or more. Moreover, it is most preferable that all solid components contained in the binder composition of the present invention are water-soluble polymer (X), water-soluble compound (Y), and polymer particles.
In the binder composition of the present invention, the mass ratio of the water-soluble polymer (X), the water-soluble compound (Y), and the polymer particles (mass of the water-soluble polymer (X): of the water-soluble compound (Y)) Mass: mass of polymer particles) is not particularly limited, and is preferably 10-80:3-80:10-77, more preferably 20-70:3-50:20-60.
　本発明のバインダー組成物は、液媒体として水を含有する。
　本発明のバインダー組成物中の水の含有量は、特に制限されず、例えば、１０質量％以上とすることができ、好ましくは２０質量％以上、より好ましくは３０質量％以上、更に好ましくは４０質量％以上、特に好ましくは５０質量％以上とすることができる。本発明のバインダー組成物は、水を６０質量％以上含有してもよく、７０質量％以上含有してもよく、８０質量％以上含有してもよい。一方、本発明のバインダー組成物中の水の含有量は、９９．５質量％以下であることが実際的である。本発明のバインダー組成物中の水の含有量は、９９質量％以下ともでき、９５質量％以下ともでき、９０質量％以下ともできる。
　本発明のバインダー組成物中の水の含有量は、例えば、１０～９９．５質量％とすることができ、好ましくは２０～９９質量％、より好ましくは３０～９９質量％、より好ましくは、４０～９９質量％、より好ましくは５０～９９質量％、より好ましくは６０～９９質量％、より好ましくは７０～９５質量％、より好ましくは８０～９０質量％である。
　本発明のバインダー組成物は、水以外の液媒体を含有していてもよい。水以外の液媒体としては、例えば、水と混合したときに相分離せずに混じり合う有機溶媒（以下、水溶性有機溶媒と称す。）が挙げられ、Ｎ－メチルピロリドン、メタノール、エタノール、アセトン、テトラヒドロフラン等が好ましく挙げられる。 The binder composition of the present invention contains water as a liquid medium.
The content of water in the binder composition of the present invention is not particularly limited, and can be, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more. It can be at least 50% by mass, particularly preferably at least 50% by mass. The binder composition of the present invention may contain water in an amount of 60% by mass or more, 70% by mass or more, or 80% by mass or more. On the other hand, it is practical for the content of water in the binder composition of the present invention to be 99.5% by mass or less. The content of water in the binder composition of the present invention can be 99% by mass or less, 95% by mass or less, and 90% by mass or less.
The content of water in the binder composition of the present invention can be, for example, 10 to 99.5% by mass, preferably 20 to 99% by mass, more preferably 30 to 99% by mass, and more preferably, The content is 40 to 99% by weight, more preferably 50 to 99% by weight, more preferably 60 to 99% by weight, more preferably 70 to 95% by weight, and more preferably 80 to 90% by weight.
The binder composition of the present invention may contain a liquid medium other than water. Examples of liquid media other than water include organic solvents that mix with water without phase separation (hereinafter referred to as water-soluble organic solvents), such as N-methylpyrrolidone, methanol, ethanol, and acetone. , tetrahydrofuran, etc. are preferably mentioned.
　本発明のバインダー組成物中、水溶性高分子（Ｘ）、水溶性化合物（Ｙ）及び重合体粒子の含有量は目的に応じて適宜に設定すればよい。例えば、バインダー組成物中の水溶性高分子（Ｘ）、水溶性化合物（Ｙ）及び重合体粒子の含有量を合計で０．５～５０質量％とすることができ、好ましくは５～３０質量％、より好ましくは１０～２０質量％とすることができる。
　本発明のバインダー組成物は、水溶性高分子（Ｘ）、水溶性化合物（Ｙ）、重合体粒子、水、水以外の液媒体の他にも、目的に応じて他の成分を含有することができる。他の成分としては、例えば、多価アルコール（ヒドロキシ基を２つ以上有するアルコール）が挙げられる。
　また、本発明のバインダー組成物は、水溶性高分子（Ｘ）、水溶性化合物（Ｙ）及び重合体粒子の合成液を希釈する等により調製することもできる。そのため、本発明のバインダー組成物中には、水溶性高分子（Ｘ）、水溶性化合物（Ｙ）及び重合体粒子の合成に使用した化合物又はその反応後の副生成物が含まれていてもよい。 In the binder composition of the present invention, the contents of the water-soluble polymer (X), the water-soluble compound (Y), and the polymer particles may be appropriately set depending on the purpose. For example, the total content of the water-soluble polymer (X), water-soluble compound (Y), and polymer particles in the binder composition can be 0.5 to 50% by mass, preferably 5 to 30% by mass. %, more preferably 10 to 20% by mass.
The binder composition of the present invention may contain other components depending on the purpose in addition to the water-soluble polymer (X), the water-soluble compound (Y), the polymer particles, water, and a liquid medium other than water. Can be done. Examples of other components include polyhydric alcohols (alcohols having two or more hydroxy groups).
The binder composition of the present invention can also be prepared by diluting a synthetic solution of the water-soluble polymer (X), the water-soluble compound (Y), and the polymer particles. Therefore, even if the binder composition of the present invention contains the water-soluble polymer (X), the water-soluble compound (Y), the compound used in the synthesis of the polymer particles, or the by-product after the reaction, good.
　上記本発明のバインダー組成物は正極又は負極どちらの電極用組成物にも適用できるが、負極に用いることが好ましく、特にケイ素系活物質を有する負極の電極用組成物に用いることが好ましい。 Although the binder composition of the present invention can be applied to either a positive electrode or a negative electrode composition, it is preferably used for a negative electrode, and particularly preferably used for a negative electrode composition containing a silicon-based active material.
［電極用組成物］
　本発明の電極用組成物は、本発明のバインダー組成物と、周期律表第１族又は第２族に属する金属のイオンの挿入放出が可能な活物質（以降、単に「活物質」ともいう）と、導電助剤とを含有する。すなわち、本発明の電極用組成物は、水溶性高分子（Ｘ）、水溶性化合物（Ｙ）、重合体粒子、水、活物質、及び導電助剤を含有する組成物である。
　本発明の電極用組成物から上記活物質と上記導電助剤とを除いた残部の引張弾性率は１５００～９８００ＭＰａであることが好ましい。「本発明の電極用組成物から上記活物質と上記導電助剤とを除いた残部」は、「本発明のバインダー組成物」に相当し、その組成は本発明のバインダー組成物と同様である。「本発明の電極用組成物から上記活物質と上記導電助剤とを除いた残部の引張弾性率」は、「本発明のバインダー組成物の引張弾性率」に相当し、その試験方法及びその好ましい範囲は、本発明のバインダー組成物の引張弾性率と同様である。 [Composition for electrode]
The electrode composition of the present invention comprises the binder composition of the present invention and an active material (hereinafter also simply referred to as "active material") capable of inserting and releasing ions of metals belonging to Group 1 or Group 2 of the periodic table. ) and a conductive aid. That is, the electrode composition of the present invention is a composition containing a water-soluble polymer (X), a water-soluble compound (Y), polymer particles, water, an active material, and a conductive aid.
It is preferable that the tensile modulus of the remainder of the electrode composition of the present invention after removing the above-mentioned active material and the above-mentioned conductive support agent is 1500 to 9800 MPa. "The remainder after removing the active material and the conductive aid from the electrode composition of the present invention" corresponds to the "binder composition of the present invention," and its composition is the same as that of the binder composition of the present invention. . "The tensile modulus of the remainder of the electrode composition of the present invention after removing the active material and the conductive aid" corresponds to the "tensile modulus of the binder composition of the present invention," and the test method and its The preferred range is similar to the tensile modulus of the binder composition of the present invention.
　活物質は正極活物質でもよく、負極活物質でもよい。本発明の電極用組成物が正極活物質を含む場合、本発明の電極用組成物を、二次電池の正極活物質層形成用スラリーとして用いることができる。また、本発明の電極用組成物が負極活物質を含む場合、本発明の電極用組成物を負極活物質層形成用スラリーとして用いることができる。
　上記本発明の電極用組成物は正極又は負極どちらの電極用組成物にも適用できるが、負極の電極用組成物として用いることが好ましく、特にケイ素系活物質を含有する負極の電極用組成物として用いることが好ましい。
　本発明の電極用組成物は、必要に応じて更に他の添加剤を含むことができる。
　上記活物質、導電助剤、他の添加剤としては、特に限定されるものではなく、二次電池に常用されるものから目的に応じて適宜選択して用いればよい。 The active material may be a positive electrode active material or a negative electrode active material. When the electrode composition of the present invention contains a positive electrode active material, the electrode composition of the present invention can be used as a slurry for forming a positive electrode active material layer of a secondary battery. Moreover, when the electrode composition of the present invention contains a negative electrode active material, the electrode composition of the present invention can be used as a slurry for forming a negative electrode active material layer.
The above-mentioned electrode composition of the present invention can be applied to either a positive electrode or a negative electrode composition, but it is preferably used as a negative electrode composition, and especially a negative electrode composition containing a silicon-based active material. It is preferable to use it as
The electrode composition of the present invention can further contain other additives as necessary.
The active material, conductive aid, and other additives are not particularly limited, and may be appropriately selected from those commonly used in secondary batteries depending on the purpose.
　水溶性高分子（Ｘ）、水溶性化合物（Ｙ）及び重合体粒子の、本発明の電極用組成物中の含有量は特に制限されず、全固形分量に対して、合計で０．５～３０質量％が好ましく、１．０～２０質量％がより好ましく、１．５～１５質量％が更に好ましく、２．５～１０質量％が特に好ましい。
　本発明の電極用組成物中、水溶性高分子（Ｘ）と、水溶性化合物（Ｙ）と、重合体粒子との質量比（水溶性高分子（Ｘ）の質量：水溶性化合物（Ｙ）の質量：重合体粒子の質量）は、本発明のバインダー組成物中のこれらの質量比と同じである。
　本発明の電極用組成物中、水の含有量は、３０～７０質量％が好ましく、４０～６０質量％がより好ましく、４５～５５質量％が更に好ましい。本発明の電極用組成物が本発明のバインダー組成物を含む場合、本発明の電極用組成物は、本発明のバインダー組成物に由来する水を含み、更に、電極用組成物の調製時に加えられた水を含有していてもよい。
　本発明の電極用組成物中、固形分量は、３０～７０質量％が好ましく、４０～６０質量％がより好ましく、４５～５５質量％が更に好ましい。
　本発明の電極用組成物に含有される全ての固形分に占める、水溶性高分子（Ｘ）、水溶性化合物（Ｙ）、重合体粒子、活物質、及び導電助剤の割合は、合計で、７０質量％以上が好ましく、８０質量％以上がより好ましく、９０質量％以上が更に好ましく、９５質量％以上が特に好ましい。また、本発明の電極用組成物に含有される固形分の全てが水溶性高分子（Ｘ）、水溶性化合物（Ｙ）、重合体粒子、活物質、及び導電助剤であることが最も好ましい。 The content of the water-soluble polymer (X), the water-soluble compound (Y), and the polymer particles in the electrode composition of the present invention is not particularly limited, and the total content is from 0.5 to 0.5 based on the total solid content. It is preferably 30% by weight, more preferably 1.0 to 20% by weight, even more preferably 1.5 to 15% by weight, and particularly preferably 2.5 to 10% by weight.
In the electrode composition of the present invention, the mass ratio of the water-soluble polymer (X), the water-soluble compound (Y), and the polymer particles (mass of the water-soluble polymer (X): water-soluble compound (Y) mass of polymer particles) is the same as their mass ratio in the binder composition of the present invention.
In the electrode composition of the present invention, the water content is preferably 30 to 70% by mass, more preferably 40 to 60% by mass, and even more preferably 45 to 55% by mass. When the electrode composition of the present invention contains the binder composition of the present invention, the electrode composition of the present invention contains water derived from the binder composition of the present invention, and further contains water added at the time of preparing the electrode composition. may contain water.
In the electrode composition of the present invention, the solid content is preferably 30 to 70% by mass, more preferably 40 to 60% by mass, and even more preferably 45 to 55% by mass.
The total proportion of the water-soluble polymer (X), water-soluble compound (Y), polymer particles, active material, and conductive aid in all the solid content contained in the electrode composition of the present invention is , is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more. Moreover, it is most preferable that all of the solid components contained in the electrode composition of the present invention are the water-soluble polymer (X), the water-soluble compound (Y), the polymer particles, the active material, and the conductive additive. .
　本発明の電極用組成物は、二次電池の電極の形成に用いるに際して、せん断ひずみ０．０１％における貯蔵弾性率ＧＣ’とせん断ひずみ１０％における貯蔵弾性率ＧＤ’との差（ＧＣ’－ＧＤ’）が１００～１０００Ｐａの間にあることが好ましい。これにより、本発明のバインダー組成物による固体粒子等の均一分散性、固体粒子等に対する追従性及び結着性等の向上効果を電極用組成物においてもより享受しやすくなる。結果、本発明の電極用組成物を用いて得られる電極シートの密着性をより高め、二次電池のサイクル特性をより高めることが可能となる。
　上記せん断ひずみ０．０１％における貯蔵弾性率ＧＣ’とせん断ひずみ１０％における貯蔵弾性率ＧＤ’とは、レオメータを用いて測定することができる。具体的には、上記＜貯蔵弾性率特性１＞の充足性判断のための測定において、測定用スラリーに代えて本発明の電極用組成物を用いる以外は、同じ測定条件で測定することができる。
　本発明の電極用組成物における「せん断ひずみ０．０１％における貯蔵弾性率ＧＣ’」、「せん断ひずみ１０％における貯蔵弾性率ＧＤ’」、「せん断ひずみ０．０１％における貯蔵弾性率ＧＣ’とせん断ひずみ１０％における貯蔵弾性率ＧＤ’との差（ＧＣ’－ＧＤ’）」は、それぞれ、上述の「せん断ひずみ０．０１％における貯蔵弾性率ＧＡ’」、「せん断ひずみ１０％における貯蔵弾性率ＧＢ’」、「せん断ひずみ０．０１％における貯蔵弾性率ＧＡ’とせん断ひずみ１０％における貯蔵弾性率ＧＢ’との差（ＧＡ’－ＧＢ’）」についての好ましい範囲を適用することができる。 When the electrode composition of the present invention is used to form an electrode for a secondary battery, the difference ( G C' -G D ') is preferably between 100 and 1000 Pa. This makes it easier for the electrode composition to enjoy the effects of improving the uniform dispersibility of solid particles, followability to solid particles, binding properties, etc., by the binder composition of the present invention. As a result, it becomes possible to further improve the adhesion of the electrode sheet obtained using the electrode composition of the present invention, and to further improve the cycle characteristics of the secondary battery.
The storage elastic modulus GC ' at a shear strain of 0.01% and the storage elastic modulus GD ' at a shear strain of 10% can be measured using a rheometer. Specifically, in the measurement for determining the sufficiency of the above <storage modulus property 1>, the measurement can be performed under the same measurement conditions except that the electrode composition of the present invention is used in place of the measurement slurry. .
"Storage modulus GC ' at 0.01% shear strain", "Storage modulus GD ' at 10% shear strain", "Storage modulus G at 0.01% shear strain" in the electrode composition of the present invention Difference between C ' and storage modulus G D ' at 10% shear strain (G C '-G D ')'' are the above-mentioned 'storage modulus G A ' at shear strain 0.01%' and '"Storage modulus G B ' at 10% shear strain", "difference between storage modulus G A' at shear strain 0.01% and storage modulus G B ' at 10% shear strain (G A '-G B ' )” can be applied.
（活物質）
　本発明の電極用組成物は、周期律表第１族又は第２族に属する金属のイオンの挿入放出が可能な活物質を含有する。 (active material)
The electrode composition of the present invention contains an active material capable of intercalating and ejecting metal ions belonging to Group 1 or Group 2 of the periodic table.
－正極活物質－
　正極活物質は、周期律表第１族又は第２族に属する金属のイオンの挿入放出が可能な活物質であり、中でも可逆的にリチウムイオンを挿入及び放出できるものが好ましい。その材料は、上記特性を有するものであれば、特に制限はなく、１）遷移金属酸化物、２）有機物、３）硫黄等のＬｉと複合化できる元素、４）硫黄と金属との複合物等でもよい。
　中でも、正極活物質としては、遷移金属酸化物を用いることが好ましく、遷移金属元素Ｍａ（Ｃｏ、Ｎｉ、Ｆｅ、Ｍｎ、Ｃｕ及びＶから選択される１種以上の元素）を有する遷移金属酸化物がより好ましい。また、この遷移金属酸化物に元素Ｍｂ（リチウム以外の周期律表の第１（Ｉａ）族の金属元素、第２（ＩＩａ）族の元素、Ａｌ、Ｇａ、Ｉｎ、Ｇｅ、Ｓｎ、Ｐｂ、Ｓｂ、Ｂｉ、Ｓｉ、Ｐ又はＢ等の元素）を混合してもよい。元素Ｍｂの混合量としては、遷移金属元素Ｍａの量１００モル％に対して０～３０モル％が好ましい。遷移金属元素Ｍａに対するＬｉのモル比（Ｌｉ／Ｍａ）が０．３～２．２になるように混合して合成されたものが、より好ましい。
　遷移金属酸化物の具体例としては、（ＭＡ）層状岩塩型構造を有する遷移金属酸化物、（ＭＢ）スピネル型構造を有する遷移金属酸化物、（ＭＣ）リチウム含有遷移金属リン酸化合物、（ＭＤ）リチウム含有遷移金属ハロゲン化リン酸化合物及び（ＭＥ）リチウム含有遷移金属ケイ酸化合物等が挙げられる。 -Cathode active material-
The positive electrode active material is an active material capable of inserting and extracting ions of metals belonging to Group 1 or Group 2 of the periodic table, and among them, a material that can reversibly insert and release lithium ions is preferable. The material is not particularly limited as long as it has the above characteristics; 1) transition metal oxides, 2) organic substances, 3) elements that can be complexed with Li such as sulfur, 4) composites of sulfur and metals. etc. may be used.
Among these, it is preferable to use a transition metal oxide as the positive electrode active material, and a transition metal oxide containing a transition metal element M a (one or more elements selected from Co, Ni, Fe, Mn, Cu, and V) is preferable. more preferable. In addition, this transition metal oxide contains elements M b (metal elements of group 1 (Ia) of the periodic table other than lithium, elements of group 2 (IIa) of the periodic table, Al, Ga, In, Ge, Sn, Pb, Elements such as Sb, Bi, Si, P, or B may be mixed. The mixing amount of element M b is preferably 0 to 30 mol % with respect to 100 mol % of transition metal element M a . It is more preferable to synthesize Li by mixing the transition metal element M a with a molar ratio (Li/M a ) of 0.3 to 2.2.
Specific examples of transition metal oxides include (MA) transition metal oxides having a layered rock salt structure, (MB) transition metal oxides having a spinel structure, (MC) lithium-containing transition metal phosphate compounds, (MD ) Lithium-containing transition metal halide phosphoric acid compounds and (ME) lithium-containing transition metal silicate compounds.
　（ＭＡ）層状岩塩型構造を有する遷移金属酸化物の具体例として、ＬｉＣｏＯ２（コバルト酸リチウム［ＬＣＯ］）、ＬｉＮｉ２Ｏ２（ニッケル酸リチウム）、ＬｉＮｉ０．８５Ｃｏ０．１０Ａｌ０．０５Ｏ２（ニッケルコバルトアルミニウム酸リチウム［ＮＣＡ］）、ＬｉＮｉ１／３Ｃｏ１／３Ｍｎ１／３Ｏ２（ニッケルマンガンコバルト酸リチウム［ＮＭＣ］）及びＬｉＮｉ０．５Ｍｎ０．５Ｏ２（マンガンニッケル酸リチウム）が挙げられる。
　（ＭＢ）スピネル型構造を有する遷移金属酸化物の具体例として、ＬｉＭｎ２Ｏ４（ＬＭＯ）、ＬｉＣｏＭｎＯ４、Ｌｉ２ＦｅＭｎ３Ｏ８、Ｌｉ２ＣｕＭｎ３Ｏ８、Ｌｉ２ＣｒＭｎ３Ｏ８及びＬｉ２ＮｉＭｎ３Ｏ８が挙げられる。
　（ＭＣ）リチウム含有遷移金属リン酸化合物としては、例えば、ＬｉＦｅＰＯ４及びＬｉ３Ｆｅ２（ＰＯ４）３等のオリビン型リン酸鉄塩、ＬｉＦｅＰ２Ｏ７等のピロリン酸鉄塩、ＬｉＣｏＰＯ４等のリン酸コバルト塩並びにＬｉ３Ｖ２（ＰＯ４）３（リン酸バナジウムリチウム）等の単斜晶ナシコン型リン酸バナジウム塩が挙げられる。
　（ＭＤ）リチウム含有遷移金属ハロゲン化リン酸化合物としては、例えば、Ｌｉ２ＦｅＰＯ４Ｆ等のフッ化リン酸鉄塩、Ｌｉ２ＭｎＰＯ４Ｆ等のフッ化リン酸マンガン塩及びＬｉ２ＣｏＰＯ４Ｆ等のフッ化リン酸コバルト塩が挙げられる。
　（ＭＥ）リチウム含有遷移金属ケイ酸化合物としては、例えば、Ｌｉ２ＦｅＳｉＯ４、Ｌｉ２ＭｎＳｉＯ４及びＬｉ２ＣｏＳｉＯ４等が挙げられる。
　本発明では、（ＭＡ）層状岩塩型構造を有する遷移金属酸化物が好ましく、ＬＣＯ又はＮＭＣがより好ましい。 (MA) Specific examples of transition metal oxides having a layered rock salt type structure include LiCoO 2 (lithium cobalt oxide [LCO]), LiNi 2 O 2 (lithium nickel oxide), LiNi 0.85 Co 0.10 Al 0. 05 O 2 (nickel cobalt lithium aluminate [NCA]), LiNi 1/3 Co 1/3 Mn 1/3 O 2 (nickel manganese cobalt lithium [NMC]), and LiNi 0.5 Mn 0.5 O 2 ( lithium manganese nickelate).
(MB) Specific examples of transition metal oxides having a spinel structure include LiMn 2 O 4 (LMO), LiCoMnO 4 , Li 2 FeMn 3 O 8 , Li 2 CuMn 3 O 8 , Li 2 CrMn 3 O 8 and Li 2NiMn3O8 is mentioned .
(MC) Examples of lithium-containing transition metal phosphate compounds include olivine-type iron phosphates such as LiFePO 4 and Li 3 Fe 2 (PO 4 ) 3 , iron pyrophosphates such as LiFeP 2 O 7 , LiCoPO 4 , etc. cobalt phosphate salts and monoclinic nasicon type vanadium phosphate salts such as Li 3 V 2 (PO 4 ) 3 (lithium vanadium phosphate).
(MD) Examples of lithium-containing transition metal halide phosphate compounds include iron fluorophosphates such as Li 2 FePO 4 F, manganese fluorophosphates such as Li 2 MnPO 4 F, and Li 2 CoPO 4 F. Examples include cobalt fluorophosphate salts such as.
(ME) Examples of the lithium-containing transition metal silicate compound include Li 2 FeSiO 4 , Li 2 MnSiO 4 and Li 2 CoSiO 4 .
In the present invention, (MA) transition metal oxides having a layered rock salt type structure are preferred, and LCO or NMC is more preferred.
　正極活物質の形状は特に制限されず、粒子状が好ましい。正極活物質の平均粒径（体積基準のメジアン径Ｄ５０）は特に制限されない。例えば、０．１～５０μｍとすることができる。正極活物質を所定の粒子径にするには、粉砕機又は分級機を用い常法により調製すればよい。後述する負極活物質の所定の粒子径への調製方法も適用することができる。焼成法によって得られた正極活物質は、水、酸性水溶液、アルカリ性水溶液又は有機溶剤等にて洗浄した後使用してもよい。
　市販品の正極活物質を用いる場合、正極活物質の平均粒径は製造元のカタログ記載の値を採用し、製造元の平均粒径の情報が入手できない場合又は合成した正極活物質を用いる場合は、後述の負極活物質に記載の方法により測定、算出された値を採用する。 The shape of the positive electrode active material is not particularly limited, and a particulate shape is preferable. The average particle diameter (volume-based median diameter D50) of the positive electrode active material is not particularly limited. For example, it can be 0.1 to 50 μm. In order to make the positive electrode active material into a predetermined particle size, it may be prepared by a conventional method using a pulverizer or a classifier. A method for preparing a negative electrode active material to a predetermined particle size, which will be described later, can also be applied. The positive electrode active material obtained by the calcination method may be used after being washed with water, an acidic aqueous solution, an alkaline aqueous solution, an organic solvent, or the like.
When using a commercially available cathode active material, the average particle size of the cathode active material should be the value listed in the manufacturer's catalog. If information on the manufacturer's average particle size is not available or when using a synthesized cathode active material, The value measured and calculated by the method described in the negative electrode active material described below is adopted.
　上記焼成法により得られた化合物の化学式は、測定方法として誘導結合プラズマ（ＩＣＰ）発光分光分析法、簡便法として、焼成前後の粉体の質量差から算出できる。 The chemical formula of the compound obtained by the above firing method can be calculated using inductively coupled plasma (ICP) emission spectrometry as a measurement method, or from the difference in mass of the powder before and after firing as a simple method.
　正極活物質の表面は別の金属酸化物等の酸化物、炭素系材料等で表面被覆されていてもよい。表面被覆材としては、後述する負極活物質の表面被覆に用いうる表面被覆材を用いることができる。 The surface of the positive electrode active material may be coated with another oxide such as a metal oxide, a carbon-based material, or the like. As the surface coating material, a surface coating material that can be used for surface coating of a negative electrode active material, which will be described later, can be used.
　また、正極活物質の表面は硫黄又はリンで表面処理されていてもよい。
　更に、正極活物質の粒子表面は、上記表面被覆の前後において活性光線又は活性気体（プラズマ等）により表面処理を施されていてもよい。 Further, the surface of the positive electrode active material may be surface-treated with sulfur or phosphorus.
Furthermore, the particle surface of the positive electrode active material may be surface-treated with active light or active gas (plasma, etc.) before and after the surface coating.
　上記正極活物質は、１種を単独で用いても、２種以上を組み合わせて用いてもよい。
　正極活物質層を形成する場合、正極活物質層の単位面積（ｃｍ２）当たりの正極活物質の質量（ｍｇ）（目付量）は特に限定されるものではない。設計された電池容量に応じて、適宜に決めることができる。 The above positive electrode active materials may be used alone or in combination of two or more.
When forming a positive electrode active material layer, the mass (mg) (basis weight) of the positive electrode active material per unit area (cm 2 ) of the positive electrode active material layer is not particularly limited. It can be determined as appropriate depending on the designed battery capacity.
　本発明の電極用組成物中における正極活物質の含有量は、特に限定されず、全固形分量に対して、１０～９９質量％が好ましく、３０～９８質量％がより好ましく、５０～９７質量％が更に好ましく、５５～９５質量％が特に好ましい。 The content of the positive electrode active material in the electrode composition of the present invention is not particularly limited, and is preferably 10 to 99% by mass, more preferably 30 to 98% by mass, and 50 to 97% by mass based on the total solid content. % is more preferable, and 55 to 95% by weight is particularly preferable.
－負極活物質－
　負極活物質は、周期律表第１族又は第２族に属する金属のイオンの挿入放出が可能な活物質であり、中でも可逆的にリチウムイオンを挿入（吸蔵）及び放出できるものが好ましい。その材料は、上記特性を有するものであれば、特に制限はなく、炭素質材料、ケイ素系材料（ケイ素元素を含有する材料を意味する。）、スズ系材料（スズ元素を含有する材料を意味する。）、金属酸化物、金属複合酸化物、リチウム単体、リチウム合金等が挙げられる。中でも、炭素質材料又はケイ素系材料が信頼性の点から好ましく用いられる。 -Negative electrode active material-
The negative electrode active material is an active material capable of intercalating and deintercalating ions of metals belonging to Group 1 or Group 2 of the periodic table, and among them, a material capable of reversibly intercalating (occluding) and deintercalating lithium ions is preferable. The material is not particularly limited as long as it has the above characteristics, such as carbonaceous materials, silicon-based materials (meaning materials containing the silicon element), tin-based materials (meaning the materials containing the tin element). ), metal oxides, metal composite oxides, simple lithium, lithium alloys, etc. Among these, carbonaceous materials or silicon-based materials are preferably used from the viewpoint of reliability.
　負極活物質として用いられる炭素質材料とは、実質的に炭素からなる材料である。例えば、石油ピッチ、アセチレンブラック等のカーボンブラック、黒鉛（鱗片状黒鉛、塊状黒鉛等の天然黒鉛、気相成長黒鉛、繊維状黒鉛等の人造黒鉛、鱗片状黒鉛を特殊加工してなる膨張黒鉛等）、活性炭、カーボンファイバー、コークス、ソフトカーボン、ハードカーボン、及びＰＡＮ（ポリアクリロニトリル）系の樹脂若しくはフルフリルアルコール樹脂等の各種の合成樹脂を焼成した炭素質材料を挙げることができる。更に、ＰＡＮ系炭素繊維、セルロース系炭素繊維、ピッチ系炭素繊維、気相成長炭素繊維、脱水ＰＶＡ（ポリビニルアルコール）系炭素繊維、リグニン炭素繊維、ガラス状炭素繊維及び活性炭素繊維等の各種炭素繊維類、メソフェーズ微小球体、グラファイトウィスカー並びに平板状の黒鉛等を挙げることもできる。 The carbonaceous material used as the negative electrode active material is a material consisting essentially of carbon. Examples include petroleum pitch, carbon black such as acetylene black, graphite (natural graphite such as flaky graphite and lumpy graphite, artificial graphite such as vapor-grown graphite and fibrous graphite, expanded graphite made by specially processing flaky graphite, etc.) ), activated carbon, carbon fiber, coke, soft carbon, hard carbon, and carbonaceous materials obtained by firing various synthetic resins such as PAN (polyacrylonitrile) resin or furfuryl alcohol resin. Furthermore, various carbon fibers such as PAN carbon fiber, cellulose carbon fiber, pitch carbon fiber, vapor grown carbon fiber, dehydrated PVA (polyvinyl alcohol) carbon fiber, lignin carbon fiber, glassy carbon fiber, and activated carbon fiber. Mention may also be made of mesophase microspheres, graphite whiskers, and tabular graphite.
　負極活物質として用いられるスズ系材料（スズ系活物質）としては、例えば、Ｓｎ、ＳｎＯ、ＳｎＯ２、ＳｎＳ、ＳｎＳ２等が挙げられる。 Examples of the tin-based material (tin-based active material) used as the negative electrode active material include Sn, SnO, SnO 2 , SnS, and SnS 2 .
　負極活物質として適用される金属酸化物及び金属複合酸化物としては、周期律表第１族又は第２族に属する金属のイオン（好ましくはリチウムイオン）の挿入放出（好ましくは吸蔵及び放出）が可能な酸化物であれば特に制限されず、金属酸化物としては金属元素の酸化物（金属酸化物）及び、半金属元素の酸化物（半金属酸化物）が挙げられ、金属複合酸化物としては、金属元素の複合酸化物、金属元素と半金属元素との複合酸化物、及び、半金属元素の複合酸化物が挙げられる。
　これらの金属酸化物及び金属複合酸化物としては、非晶質酸化物が好ましく、更に金属元素と周期律表第１６族の元素との反応生成物であるカルコゲナイトも好ましく挙げられる。ここでいう非晶質とは、ＣｕＫα線を用いたＸ線回折法で、２θ値で２０°～４０°の領域に頂点を有するブロードな散乱帯を有するものを意味し、結晶性の回折線を有してもよい。
　上記非晶質酸化物及びカルコゲナイドからなる化合物群の中でも、半金属元素の非晶質酸化物、又は、上記カルコゲナイドがより好ましく、周期律表第１３（ＩＩＩＢ）族～１５（ＶＢ）族の元素（例えば、Ａｌ、Ｇａ、Ｓｉ、Ｓｎ、Ｇｅ、Ｐｂ、Ｓｂ及びＢｉ）のうちの１種単独若しくはそれらの２種以上の組み合わせからなる酸化物もしくは複合酸化物、又はカルコゲナイドが特に好ましい。非晶質酸化物及びカルコゲナイドの具体例としては、例えば、Ｇａ２Ｏ３、ＧｅＯ、ＰｂＯ、ＰｂＯ２、Ｐｂ２Ｏ３、Ｐｂ２Ｏ４、Ｐｂ３Ｏ４、Ｓｂ２Ｏ３、Ｓｂ２Ｏ４、Ｓｂ２Ｏ８Ｂｉ２Ｏ３、Ｓｂ２Ｏ８Ｓｉ２Ｏ３、Ｓｂ２Ｏ５、Ｂｉ２Ｏ３、Ｂｉ２Ｏ４、ＧｅＳ、ＰｂＳ、ＰｂＳ２、Ｓｂ２Ｓ３及びＳｂ２Ｓ５が好ましく挙げられる。 The metal oxides and metal composite oxides used as negative electrode active materials are those that can intercalate and deintercalate (preferably intercalate and deintercalate) metal ions (preferably lithium ions) belonging to Group 1 or Group 2 of the periodic table. There is no particular restriction as long as it is a possible oxide, and metal oxides include oxides of metal elements (metal oxides) and oxides of metalloid elements (metalloid oxides), and metal composite oxides include Examples include composite oxides of metal elements, composite oxides of metal elements and metalloid elements, and composite oxides of metalloid elements.
As these metal oxides and metal composite oxides, amorphous oxides are preferable, and chalcogenite, which is a reaction product of a metal element and an element of Group 16 of the periodic table, is also preferably mentioned. The term "amorphous" as used herein means that it has a broad scattering band with a peak in the 2θ value range of 20° to 40°, as determined by X-ray diffraction using CuKα rays, and the crystalline diffraction line It may have.
Among the compound group consisting of the above-mentioned amorphous oxides and chalcogenides, the amorphous oxides of metalloid elements or the above-mentioned chalcogenides are more preferable, and elements of groups 13 (IIIB) to 15 (VB) of the periodic table are preferred. Particularly preferred are oxides or composite oxides, or chalcogenides consisting of one of the following (for example, Al, Ga, Si, Sn, Ge, Pb, Sb, and Bi) or a combination of two or more thereof. Specific examples of amorphous oxides and chalcogenides include, for example, Ga 2 O 3 , GeO, PbO, PbO 2 , Pb 2 O 3 , Pb 2 O 4 , Pb 3 O 4 , Sb 2 O 3 , Sb 2 O 4 , Sb2O8Bi2O3 , Sb2O8Si2O3 , Sb2O5 , Bi2O3 , Bi2O4 , GeS , PbS , PbS2 , Sb2S3 and Sb2S 5 is preferred.
　金属（複合）酸化物及び上記カルコゲナイドは、構成成分として、チタン及びリチウムの少なくとも一方を含有していることが、高電流密度充放電特性の観点で好ましい。リチウムを含有する金属複合酸化物（リチウム複合金属酸化物）としては、例えば、酸化リチウムと上記金属（複合）酸化物若しくは上記カルコゲナイドとの複合酸化物、より具体的には、Ｌｉ２ＳｎＯ２が挙げられる。 The metal (composite) oxide and the chalcogenide preferably contain at least one of titanium and lithium as a constituent from the viewpoint of high current density charge/discharge characteristics. The metal composite oxide containing lithium (lithium composite metal oxide) is, for example, a composite oxide of lithium oxide and the above metal (composite) oxide or the above chalcogenide, more specifically, Li 2 SnO 2 Can be mentioned.
　負極活物質はチタン元素を含有することも好ましい。より具体的にはＴｉＮｂ２Ｏ７（チタン酸ニオブ酸化物［ＮＴＯ］）、Ｌｉ４Ｔｉ５Ｏ１２（チタン酸リチウム［ＬＴＯ］）がリチウムイオンの吸蔵放出時の体積変動が小さいことから急速充放電特性に優れ、電極の劣化が抑制され、リチウムイオン二次電池のサイクル特性向上が可能となる点で好ましい。 It is also preferable that the negative electrode active material contains titanium element. More specifically, TiNb 2 O 7 (niobium titanate oxide [NTO]) and Li 4 Ti 5 O 12 (lithium titanate [LTO]) have small volume fluctuations when lithium ions are absorbed and released, so they are suitable for rapid charging. It is preferable because it has excellent discharge characteristics, suppresses electrode deterioration, and makes it possible to improve the cycle characteristics of a lithium ion secondary battery.
　負極活物質としてのリチウム合金としては、二次電池の負極活物質として通常用いられる合金であれば特に制限されず、例えば、リチウムアルミニウム合金が挙げられる。 The lithium alloy as a negative electrode active material is not particularly limited as long as it is an alloy commonly used as a negative electrode active material of secondary batteries, and examples thereof include lithium aluminum alloys.
　ケイ素系材料（ケイ素系活物質）としては、ケイ素元素を含む負極活物質であり、例えば、Ｓｉ、ＳｉＯｘ（０＜ｘ≦１．５）等のケイ素材料、更には、チタン、バナジウム、クロム、マンガン、ニッケル、銅若しくはランタンを含むケイ素含有合金（例えば、ＬａＳｉ２、ＶＳｉ２）、又は組織化した活物質（例えば、ＬａＳｉ２／Ｓｉ）、他にも、上述の金属酸化物及び金属複合酸化物の記載におけるケイ素元素を含む酸化物又は複合酸化物、ＳｎＳｉＯ３、ＳｎＳｉＳ３等のケイ素元素及びスズ元素を含む活物質等が挙げられる。
　ＳｉＯｘは、それ自体を負極活物質（半金属酸化物）として用いることができ、また、電池の稼働によりＳｉを生成するため、リチウムと合金形成可能な活物質（その前駆体物質）として用いることができる。 The silicon-based material (silicon-based active material) is a negative electrode active material containing the silicon element, such as silicon materials such as Si and SiOx (0<x≦1.5), as well as titanium, vanadium, chromium, Silicon-containing alloys containing manganese, nickel, copper or lanthanum (e.g. LaSi 2 , VSi 2 ) or structured active materials (e.g. LaSi 2 /Si), as well as the metal oxides and metal composite oxides mentioned above. Examples include oxides or composite oxides containing silicon elements in the description of products, and active materials containing silicon elements and tin elements such as SnSiO 3 and SnSiS 3 .
SiOx itself can be used as a negative electrode active material (semi-metal oxide), and since Si is generated during battery operation, it can be used as an active material (its precursor material) that can form an alloy with lithium. Can be done.
　上記では負極活物質を成分に着目して説明しているが、特性の観点からは、負極活物質は、リチウムと合金形成可能な負極活物質であることが好ましい。
　リチウムと合金形成可能な負極活物質は、二次電池の負極活物質として通常用いられるものであれば特に制限されない。このような活物質として、上述のケイ素元素及び／又はスズ元素を含む負極活物質、Ａｌ及びＩｎ等の各金属が挙げられる。より高い電池容量を可能とする点でケイ素系活物質が好ましく、ケイ素元素の含有量が全構成元素の４０モル％以上であるケイ素系活物質がより好ましい。
　一般的に、これらのリチウムと合金形成可能な負極活物質を含有する負極（例えば、ケイ素系活物質を含むＳｉ負極、スズ系活物質を含むＳｎ負極）は、炭素質材料のみからなる負極（黒鉛、カーボンブラック等）に比べて、より多くのＬｉイオンを吸蔵できる。すなわち、単位質量あたりのＬｉイオンの吸蔵量が増加する。そのため、電池容量（エネルギー密度）を大きくすることができる。その結果、バッテリー駆動時間を長くすることができるという利点がある。このように、ケイ素元素及び／又はスズ元素を含む負極活物質などのリチウムと合金形成可能な負極活物質は、高容量活物質とも称される。 Although the negative electrode active material has been described above focusing on its components, from the viewpoint of characteristics, the negative electrode active material is preferably a negative electrode active material that can form an alloy with lithium.
The negative electrode active material capable of forming an alloy with lithium is not particularly limited as long as it is commonly used as a negative electrode active material of secondary batteries. Examples of such active materials include negative electrode active materials containing the silicon element and/or tin element described above, and metals such as Al and In. A silicon-based active material is preferable in that it enables higher battery capacity, and a silicon-based active material in which the content of silicon element is 40 mol % or more of all constituent elements is more preferable.
In general, negative electrodes containing negative electrode active materials that can be alloyed with lithium (e.g., Si negative electrodes containing silicon-based active materials, Sn negative electrodes containing tin-based active materials) are different from negative electrodes made only of carbonaceous materials ( It can store more Li ions than graphite, carbon black, etc.). That is, the amount of Li ions stored per unit mass increases. Therefore, battery capacity (energy density) can be increased. As a result, there is an advantage that the battery operating time can be extended. In this way, a negative electrode active material that can form an alloy with lithium, such as a negative electrode active material containing a silicon element and/or a tin element, is also referred to as a high-capacity active material.
　負極活物質の表面は別の金属酸化物等の酸化物、炭素系材料等で表面被覆されていてもよい（以下、炭素系材料で表面被覆されていることを「カーボンコートされた」と記載することがある）。表面被覆材としてはＴｉ、Ｎｂ、Ｔａ、Ｗ、Ｚｒ、Ａｌ、Ｓｉ又はＬｉを含有する金属酸化物等が挙げられる。具体的には、チタン酸スピネル、タンタル系酸化物、ニオブ系酸化物、ニオブ酸リチウム系化合物等が挙げられ、更に具体的には、Ｌｉ４Ｔｉ５Ｏ１２、Ｌｉ２Ｔｉ２Ｏ５、ＬｉＴａＯ３、ＬｉＮｂＯ３、ＬｉＡｌＯ２、Ｌｉ２ＺｒＯ３、Ｌｉ２ＷＯ４、Ｌｉ２ＴｉＯ３、Ｌｉ２Ｂ４Ｏ７、Ｌｉ３ＰＯ４、Ｌｉ２ＭｏＯ４、Ｌｉ３ＢＯ３、ＬｉＢＯ２、Ｌｉ２ＣＯ３、Ｌｉ２ＳｉＯ３、ＳｉＯ２、ＴｉＯ２、ＺｒＯ２、Ａｌ２Ｏ３、Ｂ２Ｏ３等が挙げられる。また、Ｃ、ＳｉＣ、炭素添加シリコン酸化物等の炭素系材料も表面被覆材として用いることができる。 The surface of the negative electrode active material may be coated with an oxide such as another metal oxide, a carbon-based material, etc. (hereinafter, surface coating with a carbon-based material is referred to as "carbon-coated"). ). Examples of the surface coating material include metal oxides containing Ti, Nb, Ta, W, Zr, Al, Si, or Li. Specific examples include spinel titanate, tantalum oxides, niobium oxides, lithium niobate compounds, and more specifically, Li 4 Ti 5 O 12 , Li 2 Ti 2 O 5 , LiTaO 3 , LiNbO3 , LiAlO2 , Li2ZrO3 , Li2WO4 , Li2TiO3 , Li2B4O7 , Li3PO4 , Li2MoO4 , Li3BO3 , LiBO2 , Li2 Examples include CO 3 , Li 2 SiO 3 , SiO 2 , TiO 2 , ZrO 2 , Al 2 O 3 and B 2 O 3 . Further, carbon-based materials such as C, SiC, and carbon-doped silicon oxide can also be used as surface coating materials.
　また、負極活物質の表面は硫黄又はリンで表面処理されていてもよい。
　更に、負極活物質の粒子表面は、上記表面被覆の前後において活性光線又は活性気体（プラズマ等）により表面処理を施されていてもよい。 Further, the surface of the negative electrode active material may be surface-treated with sulfur or phosphorus.
Furthermore, the particle surface of the negative electrode active material may be surface-treated with active light or active gas (plasma, etc.) before and after the surface coating.
　負極活物質は、金属元素をドープされていてもよい。ドープされる金属元素は、Ｌｉ、Ｎｉ、及びＴｉの少なくともいずれか１種であることが好ましく、Ｌｉであることがより好ましい。 The negative electrode active material may be doped with a metal element. The metal element to be doped is preferably at least one of Li, Ni, and Ti, and more preferably Li.
　本発明においては、負極活物質として、ケイ素系活物質を用いることが好ましく、酸化ケイ素（ＳｉＯｘ（０＜ｘ≦１．５））又はカーボンコートされた酸化ケイ素（カーボンコートされたＳｉＯｘ（０＜ｘ≦１．５））を用いることがより好ましく、カーボンコートされた酸化ケイ素を用いることが更に好ましい。カーボンコートされた酸化ケイ素は、さらに金属元素をドープされていてもよい。
　カーボンコートされた酸化ケイ素中に占める炭素元素の含有量の割合は特に制限されず、例えば、０．５～５質量％が好ましく、１～３質量％がより好ましい。
　酸化ケイ素又はカーボンコートされた酸化ケイ素は市販品を用いてもよい。また、カーボンコートされた酸化ケイ素は、例えば特開２０１９－２０４６８６号公報を参照して、酸化ケイ素をカーボンコートすることにより調製することもできる。
　負極活物質中の酸化ケイ素又はカーボンコートされた酸化ケイ素の含有量は特に制限されず、例えば１０～９０質量％とすることができ、１０～５０質量％が好ましく、１５～４０質量％がより好ましい。
　負極活物質が酸化ケイ素又はカーボンコートされた酸化ケイ素である場合、平均粒径は５～２０μｍが好ましい。
　本発明においては、負極活物質として、金属元素をドープされたケイ素系材料を用いることも好ましく、Ｌｉ、Ｎｉ、及びＴｉの少なくともいずれか１種をドープされたケイ素系材料がより好ましく、Ｌｉをドープされたケイ素系材料がさらに好ましい。金属元素のドープに付されるケイ素系材料としては、酸化ケイ素又はカーボンコートされた酸化ケイ素が好ましい。
　金属元素をドープされた酸化ケイ素、並びに、カーボンコート及び金属元素のドープの両方が施された酸化ケイ素としては、市販品を用いてもよい。また、例えば特開２０２２－１２１５８２号公報、国際公開第１４／１８８８５１号及び特開２０２１－１５００７７号公報等を参照して、酸化ケイ素又はカーボンコートされた酸化ケイ素に金属元素をドープすること、又は、酸化ケイ素に金属元素をドープし、必要に応じてさらにカーボンコートを施すことにより調製することもできる。
　本発明において、「カーボンコート及び金属元素のドープの両方が施された」とは、金属元素のドープを施した後、カーボンコート処理を施したもの、及び、カーボンコート処理を施した後、金属元素のドープを施したものの両方を含む意味で使用する。
　本発明においては、負極活物質として、カーボンコート及び金属元素のドープの両方が施されたケイ素系材料を用いることも好ましく、カーボンコート及び金属元素のドープの両方が施された酸化ケイ素がより好ましく、カーボンコート及びリチウムドープの両方が施された酸化ケイ素が特に好ましい。 In the present invention, it is preferable to use a silicon-based active material as the negative electrode active material, and silicon oxide (SiO x (0<x≦1.5)) or carbon-coated silicon oxide (carbon-coated SiO x (0 It is more preferable to use <x≦1.5)), and even more preferable to use carbon-coated silicon oxide. The carbon-coated silicon oxide may be further doped with a metal element.
The content ratio of the carbon element in the carbon-coated silicon oxide is not particularly limited, and is preferably 0.5 to 5% by mass, more preferably 1 to 3% by mass.
Commercially available silicon oxide or carbon-coated silicon oxide may be used. Further, carbon-coated silicon oxide can also be prepared by carbon-coating silicon oxide, for example, with reference to JP-A-2019-204686.
The content of silicon oxide or carbon-coated silicon oxide in the negative electrode active material is not particularly limited, and can be, for example, 10 to 90% by mass, preferably 10 to 50% by mass, and more preferably 15 to 40% by mass. preferable.
When the negative electrode active material is silicon oxide or carbon-coated silicon oxide, the average particle size is preferably 5 to 20 μm.
In the present invention, it is also preferable to use a silicon-based material doped with a metal element as the negative electrode active material, more preferably a silicon-based material doped with at least one of Li, Ni, and Ti. More preferred are doped silicon-based materials. The silicon-based material to be doped with the metal element is preferably silicon oxide or carbon-coated silicon oxide.
As the silicon oxide doped with a metal element and the silicon oxide coated with both a carbon coat and a metal element doped, commercially available products may be used. Further, for example, with reference to JP-A No. 2022-121582, WO 14/188851, and JP-A No. 2021-150077, doping silicon oxide or carbon-coated silicon oxide with a metal element, or It can also be prepared by doping silicon oxide with a metal element and, if necessary, further applying a carbon coat.
In the present invention, "both carbon coated and doped with a metal element" refers to a product that is doped with a metal element and then subjected to a carbon coat treatment, and a product that is subjected to a carbon coat treatment and then a metal element doped with a metal element. Used to include both elements doped.
In the present invention, it is also preferable to use, as the negative electrode active material, a silicon-based material coated with both a carbon coat and doped with a metal element, and more preferably silicon oxide coated with both a carbon coat and doped with a metal element. Particularly preferred is silicon oxide which is both carbon-coated and lithium-doped.
　負極活物質の形状は特に制限されないが粒子状が好ましい。負極活物質の平均粒径（体積基準のメジアン径Ｄ５０）は、０．１～６０μｍが好ましい。所定の粒子径にするには、粉砕機又は分級機を用い常法により調製することができる。例えば、乳鉢、ボールミル、サンドミル、振動ボールミル、衛星ボールミル、遊星ボールミル、旋回気流型ジェットミル又は篩等が好適に用いられる。粉砕時には水又はメタノール等の有機溶媒を共存させた湿式粉砕も行うことができる。所望の粒子径とするためには分級を行うことが好ましい。分級方法としては、特に限定はなく、篩、風力分級機等を所望により用いることができる。分級は乾式及び湿式ともに用いることができる。
　市販品の負極活物質を用いる場合、負極活物質の平均粒径は製造元のカタログ記載の値を採用する。
　製造元の平均粒径の情報が入手できない場合又は合成した負極活物質を用いる場合は、負極活物質を水中で分散させ、レーザー回折／散乱式粒子径分布測定装置（例えば、ＨＯＲＩＢＡ社製のＰａｒｔｉｃｌｅ　ＬＡ－９６０Ｖ２（商品名））で測定して得られる平均粒径の値（水中での体積基準のメジアン径Ｄ５０）を採用する。 The shape of the negative electrode active material is not particularly limited, but a particulate shape is preferable. The average particle diameter (volume-based median diameter D50) of the negative electrode active material is preferably 0.1 to 60 μm. A predetermined particle size can be prepared by a conventional method using a crusher or a classifier. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a swirling jet mill, a sieve, etc. are preferably used. Wet pulverization can also be carried out in the presence of water or an organic solvent such as methanol during pulverization. In order to obtain a desired particle size, it is preferable to perform classification. The classification method is not particularly limited, and a sieve, a wind classifier, etc. can be used as desired. Both dry and wet classification can be used.
When using a commercially available negative electrode active material, the average particle diameter of the negative electrode active material is the value stated in the manufacturer's catalog.
If information on the average particle size from the manufacturer is not available or if a synthesized negative electrode active material is used, the negative electrode active material is dispersed in water and measured using a laser diffraction/scattering particle size distribution measuring device (for example, Particle LA manufactured by HORIBA). -960V2 (trade name)), the average particle diameter value (volume-based median diameter D50 in water) is adopted.
　負極活物質は、１種を単独で用いても、２種以上を組み合わせて用いてもよい。その中でも、ケイ素系活物質と炭素質材料の組み合わせが好ましく、ケイ素系活物質と黒鉛との組み合わせがより好ましく、酸化ケイ素又はカーボンコートされた酸化ケイ素と、黒鉛との組み合わせがさらに好ましい。酸化ケイ素及びカーボンコートされた酸化ケイ素は、それぞれ、上述の金属元素のドープが施された酸化ケイ素及びカーボンコート及び金属元素のドープの両方が施された酸化ケイ素であってもよい。ドープされる金属元素は、Ｌｉ、Ｎｉ及びＴｉの少なくともいずれか１種であることが好ましく、Ｌｉ、Ｎｉ及びＴｉのいずれかであることがより好ましい。
　ケイ素系活物質と黒鉛とを組み合わせる場合、黒鉛に対するケイ素系活物質の質量比率（ケイ素系活物質／黒鉛）は２以下が好ましく、１以下がより好ましく、０．５以下が更に好ましい。黒鉛に対するケイ素系活物質の質量比率の下限値に特に制限はないが、０．０５以上が実際的である。 The negative electrode active materials may be used alone or in combination of two or more. Among these, a combination of a silicon-based active material and a carbonaceous material is preferred, a combination of a silicon-based active material and graphite is more preferred, and a combination of silicon oxide or carbon-coated silicon oxide and graphite is even more preferred. The silicon oxide and the carbon-coated silicon oxide may be silicon oxide doped with the above-mentioned metal element and silicon oxide coated with both a carbon coat and a metal element dope, respectively. The metal element to be doped is preferably at least one of Li, Ni, and Ti, and more preferably one of Li, Ni, and Ti.
When combining a silicon-based active material and graphite, the mass ratio of the silicon-based active material to graphite (silicon-based active material/graphite) is preferably 2 or less, more preferably 1 or less, and even more preferably 0.5 or less. Although there is no particular restriction on the lower limit of the mass ratio of silicon-based active material to graphite, 0.05 or more is practical.
　負極活物質の比表面積（ＢＥＴ比表面積）は、０．１～５０ｍ２／ｇが好ましい。
　市販品の負極活物質を用いる場合、負極活物質の比表面積は製造元のカタログ記載の値を採用する。
　製造元の比表面積の情報が入手できない場合又は合成した負極活物質を用いる場合は、負極活物質を試料管に詰めて窒素をフローして乾燥させ、比表面積／細孔分布測定装置（例えば、マイクロトラック・ベル社製ＢＥＬＳＯＲＰ　ＭＩＮＩ）を使用して測定する窒素吸着法によるＢＥＴ（一点）法により算出して得られる比表面積（ＢＥＴ比表面積）の値を採用する。 The specific surface area (BET specific surface area) of the negative electrode active material is preferably 0.1 to 50 m 2 /g.
When using a commercially available negative electrode active material, the specific surface area of the negative electrode active material uses the value described in the manufacturer's catalog.
If specific surface area information from the manufacturer is not available or if a synthesized negative electrode active material is used, pack the negative electrode active material into a sample tube, dry it with a flow of nitrogen, and use a specific surface area/pore distribution measuring device (e.g., micro The value of the specific surface area (BET specific surface area) calculated by the BET (single point) method using the nitrogen adsorption method measured using BELSORP MINI manufactured by Track Bell Co., Ltd. is used.
　負極活物質としては、上記＜貯蔵弾性率特性１＞の充足性の判断のために用いる、カーボンコートされた酸化ケイ素及び黒鉛を好ましく用いることができる。これらの平均粒径及び比表面積の好ましい範囲については上述した通りである。 As the negative electrode active material, carbon-coated silicon oxide and graphite, which are used for determining the sufficiency of the above-mentioned <Storage Modulus Characteristics 1>, can be preferably used. The preferred ranges of these average particle diameters and specific surface areas are as described above.
　負極活物質の、本発明の電極用組成物中における含有量は、特に限定されず、全固形分量に対して、１０～９９質量％であることが好ましく、３０～９８質量％がより好ましく、４５～９７質量が更に好ましく、５５～９５質量％が更に好ましく、６５～９５質量％が更に好ましく、７５～９５質量％が特に好ましい。 The content of the negative electrode active material in the electrode composition of the present invention is not particularly limited, and is preferably 10 to 99% by mass, more preferably 30 to 98% by mass, based on the total solid content. It is more preferably 45 to 97% by weight, even more preferably 55 to 95% by weight, even more preferably 65 to 95% by weight, and particularly preferably 75 to 95% by weight.
　本発明において、負極活物質層を電池の充電により形成する場合、上記負極活物質に代えて、二次電池内に発生する周期律表第１族若しくは第２族に属する金属のイオンを用いることができる。このイオンを電子と結合させて金属として析出させることで、負極活物質層を形成できる。 In the present invention, when the negative electrode active material layer is formed by charging the battery, metal ions belonging to Group 1 or Group 2 of the periodic table generated in the secondary battery may be used instead of the negative electrode active material. Can be done. By combining these ions with electrons and depositing them as metal, a negative electrode active material layer can be formed.
（導電助剤）
　本発明の電極用組成物は、導電助剤を含有する。
　導電助剤としては、特に制限はなく、一般的な導電助剤として知られているものを用いることができる。例えば、電子伝導性材料である、アセチレンブラック、ケッチェンブラック、ファーネスブラック等のカーボンブラック類、ニードルコークス等の無定形炭素、気相成長炭素繊維若しくはカーボンナノチューブ等の炭素繊維類、グラフェン若しくはフラーレン等の炭素質材料であってもよいし、銅、ニッケル等の金属粉、金属繊維でもよく、ポリアニリン、ポリピロール、ポリチオフェン、ポリアセチレン、ポリフェニレン誘導体等の導電性高分子を用いてもよい。導電助剤としてはアセチレンブラックが好ましい。
　本発明において、上記の導電助剤のうち、電池を充放電した際に周期律表第１族又は第２族に属する金属のイオン（例えば、Ｌｉ）の挿入と放出が起きず、活物質として機能しないものを導電助剤とする。したがって、導電助剤の中でも、電池を充放電した際に活物質層中において活物質として機能しうるものは、導電助剤ではなく活物質に分類する。電池を充放電した際に活物質として機能するか否かは、一義的ではなく、活物質との組み合わせにより決定される。 (conductivity aid)
The electrode composition of the present invention contains a conductive additive.
There are no particular limitations on the conductive aid, and those known as general conductive aids can be used. For example, electron conductive materials such as carbon black such as acetylene black, Ketjen black, and furnace black, amorphous carbon such as needle coke, carbon fibers such as vapor-grown carbon fiber or carbon nanotubes, graphene or fullerene, etc. The material may be a carbonaceous material, metal powder such as copper or nickel, or metal fiber, or a conductive polymer such as polyaniline, polypyrrole, polythiophene, polyacetylene, or polyphenylene derivative. Acetylene black is preferred as the conductive aid.
In the present invention, among the above-mentioned conductive additives, metal ions belonging to Group 1 or Group 2 of the periodic table (for example, Li) are not inserted or released when the battery is charged and discharged, and as an active material. What is not functional is used as a conductive aid. Therefore, among conductive aids, those that can function as active materials in the active material layer when the battery is charged and discharged are classified as active materials rather than conductive aids. Whether or not it functions as an active material when charging and discharging a battery is not unique, but is determined by the combination with the active material.
　導電助剤は、１種を単独で用いても、２種以上を組み合わせて用いてもよい。
　導電助剤の、本発明の電極用組成物中の含有量は、全固形分量に対して、０．５～６０質量％が好ましく、１．０～５０質量％がより好ましく、１．５～４０質量％が更に好ましく、２．５～３５質量％が特に好ましい。導電助剤の、本発明の電極用組成物中の含有量は、全固形分量に対して、２．５～２５質量％とすることもでき、３．０～２０質量％とすることもでき、４．０～１０質量％とすることもできる。 The conductive aids may be used alone or in combination of two or more.
The content of the conductive aid in the electrode composition of the present invention is preferably 0.5 to 60% by mass, more preferably 1.0 to 50% by mass, and 1.5 to 50% by mass based on the total solid content. 40% by weight is more preferable, and 2.5 to 35% by weight is particularly preferable. The content of the conductive aid in the electrode composition of the present invention can be 2.5 to 25% by mass, or 3.0 to 20% by mass, based on the total solid content. , 4.0 to 10% by mass.
　導電助剤の形状は、特に制限されないが、粒子状が好ましい。
　導電助剤の平均粒径（体積基準のメジアン径Ｄ５０）は、特に限定されず、例えば、０．０１～５０μｍが好ましく、０．０２～１０．０μｍがより好ましく、０．０２～０．２μｍが更に好ましい。
　市販品の導電助剤を用いる場合、導電助剤の平均粒径は製造元のカタログ記載の値を採用する。
　製造元の平均粒径の情報が入手できない場合又は合成した導電助剤を用いる場合は、導電助剤の平均粒径は、前述した負極活物質の平均粒径（水中での体積基準のメジアン径Ｄ５０）の測定方法を適用して得られた値を採用すればよい。 The shape of the conductive aid is not particularly limited, but is preferably particulate.
The average particle size (volume-based median diameter D50) of the conductive additive is not particularly limited, and is, for example, preferably 0.01 to 50 μm, more preferably 0.02 to 10.0 μm, and 0.02 to 0.2 μm. is even more preferable.
When using a commercially available conductive aid, the average particle diameter of the conductive aid is the value listed in the manufacturer's catalog.
If information on the average particle size from the manufacturer is not available or when using a synthesized conductive additive, the average particle size of the conductive additive should be the average particle diameter of the negative electrode active material described above (volume-based median diameter D50 in water). ) may be used.
　導電助剤の比表面積（ＢＥＴ比表面積）は、１０～１００ｍ２／ｇが好ましい。
　市販品の導電助剤を用いる場合、導電助剤の比表面積は製造元のカタログ記載の値を採用する。
　製造元の比表面積の情報が入手できない場合又は合成した導電助剤を用いる場合は、前述した負極活物質の比表面積（ＢＥＴ比表面積）の測定方法（窒素吸着法によるＢＥＴ法）を適用して得られた値を採用すればよい。 The specific surface area (BET specific surface area) of the conductive additive is preferably 10 to 100 m 2 /g.
When using a commercially available conductive aid, the value stated in the manufacturer's catalog is used for the specific surface area of the conductive aid.
If information on the specific surface area from the manufacturer is not available or when using a synthesized conductive aid, the method for measuring the specific surface area (BET specific surface area) of the negative electrode active material described above (BET method using nitrogen adsorption method) can be applied. The value given should be adopted.
　導電助剤としては、上記＜貯蔵弾性率特性１＞の充足性の判断のために用いる、アセチレンブラックを好ましく用いることができる。アセチレンブラックの平均粒径及び比表面積の好ましい範囲については上述した通りである。 As the conductive aid, acetylene black, which is used for determining the sufficiency of the above-mentioned <Storage Modulus Characteristics 1>, can be preferably used. The preferred ranges of the average particle diameter and specific surface area of acetylene black are as described above.
（他の添加剤）
　本発明の電極用組成物は、上記各成分以外の他の成分として、所望により、リチウム塩、イオン液体、増粘剤、消泡剤、レベリング剤、脱水剤、酸化防止剤等を含有することができる。
　上記活物質、導電助剤、他の添加剤に関し、例えば、国際公開第２０１９／２０３３３４号、特開２０１５－４６３８９号公報等を参照することができる。 (Other additives)
The electrode composition of the present invention may optionally contain a lithium salt, an ionic liquid, a thickener, an antifoaming agent, a leveling agent, a dehydrating agent, an antioxidant, etc. as other components other than the above-mentioned components. Can be done.
Regarding the above-mentioned active material, conductive aid, and other additives, reference can be made to, for example, International Publication No. 2019/203334, JP 2015-46389, etc.
［二次電池用バインダー組成物及び電極用組成物の調製方法］
　本発明のバインダー組成物は、水溶性高分子（Ｘ）、水溶性化合物（Ｙ）、重合体粒子、水、更には適宜に、任意の他の成分を、例えば通常用いる各種の混合機で混合することにより、混合物として、好ましくはスラリーとして、調製することができる。
　本発明の電極用組成物の場合は、上記に加えて、活物質及び導電助剤を、更には適宜に、任意の他の添加剤を、混合することにより、混合物として、好ましくはスラリーとして調製する。
　混合方法は特に制限されず、一括して混合してもよく、順次混合してもよい。また、複数の成分を混合して得られる混合物を他の成分と混合してもよい。本発明の電極用組成物を得る場合、本発明のバインダー組成物を調製してから、活物質及び導電助剤等の成分を混合してもよく、本発明のバインダー組成物の成分の一部と活物質及び導電助剤等の成分とを混合してから、残りのバインダー組成物の成分を混合してもよい。例えば、水溶性高分子（Ｘ）、水溶性化合物（Ｙ）、活物質、導電助剤及び水を混合した後、水と重合体粒子を加えて更に混合して、本発明の電極用組成物を得ることもできる。 [Preparation method of binder composition for secondary battery and composition for electrode]
The binder composition of the present invention can be prepared by mixing a water-soluble polymer (X), a water-soluble compound (Y), polymer particles, water, and optionally any other components using, for example, various commonly used mixers. By doing so, a mixture, preferably a slurry, can be prepared.
In the case of the electrode composition of the present invention, in addition to the above, an active material and a conductive additive are mixed, and optionally, other additives are mixed to form a mixture, preferably a slurry. do.
The mixing method is not particularly limited, and may be mixed all at once or sequentially. Further, a mixture obtained by mixing a plurality of components may be mixed with other components. When obtaining the electrode composition of the present invention, after preparing the binder composition of the present invention, components such as an active material and a conductive aid may be mixed, and some of the components of the binder composition of the present invention may be mixed. After mixing the components such as the active material and the conductive additive, the remaining components of the binder composition may be mixed. For example, after mixing a water-soluble polymer (X), a water-soluble compound (Y), an active material, a conductive agent, and water, water and polymer particles are added and further mixed to prepare the electrode composition of the present invention. You can also get
［電極シート］
　本発明の電極シートは、本発明の電極用組成物を用いて形成された層（電極活物質層、すなわち、負極活物質層又は正極活物質層）を有する。本発明の電極シートは、本発明の電極用組成物を用いて形成された電極活物質層を有する電極シートであればよく、電極活物質層が、集電体等の基材上に形成されているシートでも、基材を有さず、電極活物質層（負極活物質層又は正極活物質層）だけで形成されているシートであってもよい。この電極シートは、通常、集電体上に電極活物質層を積層した構成のシートである。本発明の電極シートは、他の層として、例えば、剥離シート等の保護層、コート層を有してもよい。
　本発明の電極シートは、二次電池の負極活物質層又は正極活物質層を構成する材料、あるいは、負極集電体と負極活物質層の積層体（負極層）又は正極集電体と正極活物質層の積層体（正極層）として好適に用いることができる。 [Electrode sheet]
The electrode sheet of the present invention has a layer (electrode active material layer, that is, a negative electrode active material layer or a positive electrode active material layer) formed using the electrode composition of the present invention. The electrode sheet of the present invention may be an electrode sheet having an electrode active material layer formed using the electrode composition of the present invention, and the electrode active material layer may be formed on a base material such as a current collector. It may be a sheet that does not have a base material and is formed only of an electrode active material layer (a negative electrode active material layer or a positive electrode active material layer). This electrode sheet usually has a structure in which an electrode active material layer is laminated on a current collector. The electrode sheet of the present invention may have other layers such as a protective layer such as a release sheet and a coating layer.
The electrode sheet of the present invention is a material constituting a negative electrode active material layer or a positive electrode active material layer of a secondary battery, or a laminate of a negative electrode current collector and a negative electrode active material layer (negative electrode layer), or a positive electrode current collector and a positive electrode. It can be suitably used as a laminate of active material layers (positive electrode layer).
　本発明の電極シートが集電体を有する場合、本発明の電極シートを構成する集電体は、電子伝達体であり、通常はフィルムシート状である。集電体は、活物質に応じて適宜選択することができる。
　正極集電体の構成材料としては、アルミニウム、アルミニウム合金、ステンレス鋼、ニッケル、及び、チタンが挙げられ、アルミニウム又はアルミニウム合金が好ましい。なお、正極集電体としては、アルミニウム又はステンレス鋼の表面をカーボン、ニッケル、チタン又は銀で処理し、コート層（薄膜）を形成したものも挙げられる。
　負極集電体の構成材料としては、アルミニウム、銅、銅合金、ステンレス鋼、ニッケル、及び、チタンが挙げられ、アルミニウム、銅、銅合金、又は、ステンレス鋼が好ましい。なお、負極集電体としては、アルミニウム、銅、銅合金又はステンレス鋼の表面をカーボン、ニッケル、チタン又は銀を処理し、コート層（薄膜）を形成したものも挙げられる。 When the electrode sheet of the present invention has a current collector, the current collector constituting the electrode sheet of the present invention is an electron carrier and is usually in the form of a film sheet. The current collector can be appropriately selected depending on the active material.
Examples of the constituent material of the positive electrode current collector include aluminum, aluminum alloy, stainless steel, nickel, and titanium, with aluminum or aluminum alloy being preferred. Note that examples of the positive electrode current collector include those obtained by treating the surface of aluminum or stainless steel with carbon, nickel, titanium, or silver to form a coating layer (thin film).
Examples of the constituent material of the negative electrode current collector include aluminum, copper, copper alloy, stainless steel, nickel, and titanium, with aluminum, copper, copper alloy, or stainless steel being preferred. Note that examples of the negative electrode current collector include those obtained by treating the surface of aluminum, copper, copper alloy, or stainless steel with carbon, nickel, titanium, or silver to form a coating layer (thin film).
　本発明の電極シートを構成する正極活物質層の厚さは特に制限されず、例えば、５～５００μｍとすることができ、２０～２００μｍが好ましい。
　また、本発明の電極シートを構成する正極集電体の厚さは特に制限されず、例えば、１０～１００μｍとすることができ、１０～５０μｍが好ましい。 The thickness of the positive electrode active material layer constituting the electrode sheet of the present invention is not particularly limited, and can be, for example, 5 to 500 μm, preferably 20 to 200 μm.
Further, the thickness of the positive electrode current collector constituting the electrode sheet of the present invention is not particularly limited, and may be, for example, 10 to 100 μm, preferably 10 to 50 μm.
　本発明の電極シートを構成する負極活物質層の厚さは特に制限されず、例えば、５～５００μｍとすることができ、２０～２００μｍが好ましい。
　また、本発明の電極シートを構成する負極集電体の厚さは特に制限されず、例えば、１０～１００μｍとすることができ、１０～５０μｍが好ましい。 The thickness of the negative electrode active material layer constituting the electrode sheet of the present invention is not particularly limited, and can be, for example, 5 to 500 μm, preferably 20 to 200 μm.
Further, the thickness of the negative electrode current collector constituting the electrode sheet of the present invention is not particularly limited, and can be, for example, 10 to 100 μm, preferably 10 to 50 μm.
［電極シートの製造方法］
　本発明の電極シートは、本発明の電極用組成物を用いて電極活物質層を形成することにより得ることができる。例えば、本発明の電極用組成物を用いて製膜することにより、本発明の電極シートを製造することができる。具体的には、集電体等を基材として、その上（他の層を介していてもよい）に本発明の電極用組成物を塗布して塗膜を形成し、これを乾燥して、基材上に活物質層（塗布乾燥層）を有する電極シートを得ることができる。
　また、本発明の二次電池は、上記電極シートの製造方法により得られた電極シートを二次電池の電極（正極及び負極）の少なくとも一方に組み込むことにより得ることができる。 [Method for manufacturing electrode sheet]
The electrode sheet of the present invention can be obtained by forming an electrode active material layer using the electrode composition of the present invention. For example, the electrode sheet of the present invention can be manufactured by forming a film using the electrode composition of the present invention. Specifically, a current collector or the like is used as a base material, and the electrode composition of the present invention is applied thereon (possibly via another layer) to form a coating film, and this is dried. , it is possible to obtain an electrode sheet having an active material layer (coated dry layer) on a base material.
Moreover, the secondary battery of the present invention can be obtained by incorporating the electrode sheet obtained by the above method for manufacturing an electrode sheet into at least one of the electrodes (positive electrode and negative electrode) of the secondary battery.
［二次電池］
　本発明の二次電池は、正極活物質層及び負極活物質層の少なくとも１つの層が、本発明の電極用組成物を用いて形成された層である。
　本発明の二次電池について、非水電解液二次電池の形態を例にして説明するが、本発明の二次電池は非水電解液二次電池に限定されるものではなく、二次電池全般を広く包含するものである。 [Secondary battery]
In the secondary battery of the present invention, at least one of the positive electrode active material layer and the negative electrode active material layer is a layer formed using the electrode composition of the present invention.
The secondary battery of the present invention will be explained using the form of a non-aqueous electrolyte secondary battery as an example, but the secondary battery of the present invention is not limited to a non-aqueous electrolyte secondary battery. It broadly encompasses everything.
　本発明の好ましい一実施形態である非水電解液二次電池は、正極と、負極と、正極と負極との間に配されたセパレータとを含む構成を有する。正極は、正極集電体と、この正極集電体に接する正極活物質層とを有し、負極は、負極集電体と、この負極集電体に接する負極活物質層とを有する。本発明の非水電解液二次電池は、上記正極活物質層及び上記負極活物質層の少なくとも１つの層が、本発明の電極用組成物を用いて形成されている。なお、本発明の非水電解液二次電池には、正極活物質層及び負極活物質層のいずれか一方のみを有し、この本発明の非水電解液二次電池が有する電極活物質層が本発明の電極用組成物を用いて形成されている構成の非水電解液二次電池も含まれる。本発明の非水電解液二次電池は、正極と負極との間に非水電解液を満たすことにより、充放電により二次電池として機能する。 A non-aqueous electrolyte secondary battery that is a preferred embodiment of the present invention has a configuration including a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode. The positive electrode has a positive electrode current collector and a positive electrode active material layer in contact with the positive electrode current collector, and the negative electrode has a negative electrode current collector and a negative electrode active material layer in contact with the negative electrode current collector. In the non-aqueous electrolyte secondary battery of the present invention, at least one of the positive electrode active material layer and the negative electrode active material layer is formed using the electrode composition of the present invention. Note that the nonaqueous electrolyte secondary battery of the present invention has only one of a positive electrode active material layer and a negative electrode active material layer, and the electrode active material layer of the nonaqueous electrolyte secondary battery of the present invention has only one of a positive electrode active material layer and a negative electrode active material layer. It also includes a non-aqueous electrolyte secondary battery formed using the electrode composition of the present invention. The non-aqueous electrolyte secondary battery of the present invention functions as a secondary battery by charging and discharging by filling a non-aqueous electrolyte between the positive electrode and the negative electrode.
　図１は、一般的な非水電解液二次電池１０の積層構造を、電池として作動させる際の作動電極も含めて、模式化して示す断面図である。非水電解液二次電池１０は、負極側からみて、負極集電体１、負極活物質層２、セパレータ３、正極活物質層４、正極集電体５を、この順に有する積層構造を有している。負極活物質層と正極活物質層との間は非水電解液（図示せず）で満たされ、かつセパレータ３で分断されている。セパレータ３は空孔を有し、通常の電池の使用状態では電解液及びイオンをこの空孔により透過しながら正負極間を絶縁する正負極分離膜として機能する。このような構造により、例えばリチウムイオン二次電池であれば、充電時には外部回路を通って負極側に電子（ｅ－）が供給され、同時に電解液を介して正極からリチウムイオン（Ｌｉ＋）が移動してきて負極に蓄積される。一方、放電時には、負極に蓄積されたリチウムイオン（Ｌｉ＋）が電解液を介して正極側に戻され、作動部位６には電子が供給される。図示した例では、作動部位６に電球を採用しており、放電によりこれが点灯するようにされている。
　本発明において、負極集電体１と負極活物質層２とを合わせて負極と称し、正極活物質層４と正極集電体５とを合わせて正極と称している。 FIG. 1 is a cross-sectional view schematically showing the laminated structure of a general non-aqueous electrolyte secondary battery 10, including an operating electrode when operating the battery. The nonaqueous electrolyte secondary battery 10 has a laminated structure including a negative electrode current collector 1, a negative electrode active material layer 2, a separator 3, a positive electrode active material layer 4, and a positive electrode current collector 5 in this order when viewed from the negative electrode side. are doing. The space between the negative electrode active material layer and the positive electrode active material layer is filled with a non-aqueous electrolyte (not shown) and separated by a separator 3. The separator 3 has pores, and functions as a positive and negative electrode separation membrane that insulates between the positive and negative electrodes while allowing electrolyte and ions to pass through the pores during normal use of the battery. With such a structure, for example, in the case of a lithium ion secondary battery, during charging, electrons (e - ) are supplied to the negative electrode side through the external circuit, and at the same time, lithium ions (Li + ) are supplied from the positive electrode through the electrolyte. It migrates and accumulates on the negative electrode. On the other hand, during discharging, lithium ions (Li + ) accumulated in the negative electrode are returned to the positive electrode side via the electrolyte, and electrons are supplied to the operating region 6 . In the illustrated example, a light bulb is used as the operating portion 6, and the light bulb is lit by discharge.
In the present invention, the negative electrode current collector 1 and the negative electrode active material layer 2 are collectively referred to as a negative electrode, and the positive electrode active material layer 4 and the positive electrode current collector 5 are collectively referred to as a positive electrode.
　本発明の二次電池は、本発明の電極用組成物を用いて形成された正極活物質層及び負極活物質層の少なくともいずれか１つを具備してなること以外は、電解液（水系電解液、非水電解液）又は固体電解質材料等の電解質、セパレータ等のその他の各部材等は、特に制限されない。これらの材料及び部材等は、通常の二次電池に用いられるものを適宜に適用することができる。また、本発明の二次電池の作製方法についても、本発明の電極用組成物を用いて正極活物質層及び負極活物質層の少なくともいずれか１つを形成すること以外は、通常の方法を適宜に採用することができる。これらの二次電池に通常使用される部材及び作製方法については、例えば、特開２０１６－２０１３０８号公報、特開２００５－１０８８３５号公報、特開２０１２－１８５９３８号公報及び国際公開第２０２０／０６７１０６号等を適宜に参照することができる。
　非水電解液の好ましい形態について、より詳しく説明する。 The secondary battery of the present invention includes an electrolytic solution (aqueous electrolyte There are no particular restrictions on the electrolytes such as liquid, non-aqueous electrolytes) or solid electrolyte materials, and other members such as separators. As these materials and members, those used in ordinary secondary batteries can be used as appropriate. Further, regarding the method for producing the secondary battery of the present invention, a normal method is followed except that at least one of the positive electrode active material layer and the negative electrode active material layer is formed using the electrode composition of the present invention. It can be adopted as appropriate. Regarding the members and manufacturing methods normally used for these secondary batteries, for example, JP2016-201308A, JP2005-108835A, JP2012-185938A, and International Publication No. 2020/067106. etc. can be referred to as appropriate.
A preferred form of the non-aqueous electrolyte will be explained in more detail.
（電解質）
　非水電解液に用いる電解質は周期律表第１族又は第２族に属する金属イオンの塩が好ましい。使用する金属イオンの塩は非水電解液の使用目的により適宜選択される。例えば、リチウム塩、カリウム塩、ナトリウム塩、カルシウム塩、マグネシウム塩等が挙げられ、二次電池等に使用される場合には、出力の観点からリチウム塩が好ましい。非水電解液をリチウムイオン二次電池用電解液として用いる場合には、金属イオンの塩としてリチウム塩を選択すればよい。リチウム塩としては、リチウムイオン二次電池用電解液の電解質に通常用いられるリチウム塩が好ましく、例えば、以下のリチウム塩が挙げられる。 (Electrolytes)
The electrolyte used in the nonaqueous electrolyte is preferably a salt of a metal ion belonging to Group 1 or Group 2 of the periodic table. The metal ion salt used is appropriately selected depending on the intended use of the non-aqueous electrolyte. Examples include lithium salts, potassium salts, sodium salts, calcium salts, magnesium salts, etc. When used in secondary batteries etc., lithium salts are preferred from the viewpoint of output. When a non-aqueous electrolyte is used as an electrolyte for a lithium ion secondary battery, a lithium salt may be selected as the metal ion salt. As the lithium salt, lithium salts commonly used in electrolytes of electrolytes for lithium ion secondary batteries are preferable, and examples thereof include the following lithium salts.
（Ｌ－１）無機リチウム塩：ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＡｓＦ６、ＬｉＳｂＦ６等の無機フッ化物塩、ＬｉＣｌＯ４、ＬｉＢｒＯ４、ＬｉＩＯ４等の過ハロゲン酸塩、ＬｉＡｌＣｌ４等の無機塩化物塩等 (L-1) Inorganic lithium salt: Inorganic fluoride salts such as LiPF 6 , LiBF 4 , LiAsF 6 , LiSbF 6 , perhalogenates such as LiClO 4 , LiBrO 4 , LiIO 4 , inorganic chloride salts such as LiAlCl 4 etc
（Ｌ－２）含フッ素有機リチウム塩：ＬｉＣＦ３ＳＯ３等のパーフルオロアルカンスルホン酸塩、ＬｉＮ（ＣＦ３ＳＯ２）２、ＬｉＮ（ＣＦ３ＣＦ２ＳＯ２）２、ＬｉＮ（ＦＳＯ２）２、ＬｉＮ（ＣＦ３ＳＯ２）（Ｃ４Ｆ９ＳＯ２）等のフルオロスルホニルイミド塩又はパーフルオロアルカンスルホニルイミド塩、ＬｉＣ（ＣＦ３ＳＯ２）３等のパーフルオロアルカンスルホニルメチド塩、Ｌｉ［ＰＦ５（ＣＦ２ＣＦ２ＣＦ３）］、Ｌｉ［ＰＦ４（ＣＦ２ＣＦ２ＣＦ３）２］、Ｌｉ［ＰＦ３（ＣＦ２ＣＦ２ＣＦ３）３］、Ｌｉ［ＰＦ５（ＣＦ２ＣＦ２ＣＦ２ＣＦ３）］、Ｌｉ［ＰＦ４（ＣＦ２ＣＦ２ＣＦ２ＣＦ３）２］、Ｌｉ［ＰＦ３（ＣＦ２ＣＦ２ＣＦ２ＣＦ３）３］等のパーフルオロアルキルフッ化リン酸塩等 (L-2) Fluorine-containing organic lithium salt: perfluoroalkanesulfonate such as LiCF 3 SO 3 , LiN(CF 3 SO 2 ) 2 , LiN(CF 3 CF 2 SO 2 ) 2 , LiN(FSO 2 ) 2 , fluorosulfonylimide salts or perfluoroalkanesulfonylimide salts such as LiN(CF 3 SO 2 ) (C 4 F 9 SO 2 ), perfluoroalkanesulfonyl methide salts such as LiC(CF 3 SO 2 ) 3 , Li[ PF 5 (CF 2 CF 2 CF 3 )], Li [PF 4 (CF 2 CF 2 CF 3 ) 2 ], Li [PF 3 (CF 2 CF 2 CF 3 ) 3 ], Li [PF 5 (CF 2 CF 2 CF 2 CF 3 )], Li[PF 4 (CF 2 CF 2 CF 2 CF 3 ) 2 ], Li[PF 3 (CF 2 CF 2 CF 2 CF 3 ) 3 ], and other perfluoroalkyl fluorinated phosphoric acids. salt etc.
（Ｌ－３）オキサラトボレート塩：リチウムビス（オキサラト）ボレート、リチウムジフルオロオキサラトボレート等 (L-3) Oxalatoborate salt: lithium bis(oxalato)borate, lithium difluorooxalatoborate, etc.
　これらのなかで、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＡｓＦ６、ＬｉＳｂＦ６、ＬｉＣｌＯ４、Ｌｉ（Ｒｆ１ＳＯ３）、ＬｉＮ（Ｒｆ１ＳＯ２）２、ＬｉＮ（ＦＳＯ２）２、又はＬｉＮ（Ｒｆ１ＳＯ２）（Ｒｆ２ＳＯ２）が好ましく、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＮ（Ｒｆ１ＳＯ２）２、ＬｉＮ（ＦＳＯ２）２又はＬｉＮ（Ｒｆ１ＳＯ２）（Ｒｆ２ＳＯ２）が更に好ましい。ここで、Ｒｆ１及びＲｆ２はそれぞれパーフルオロアルキル基を示し、炭素数は１～６であることが好ましい。
　なお、非水電解液に用いる電解質は、１種を単独で使用しても、２種以上を任意に組み合わせて使用してもよい。 Among these, LiPF 6 , LiBF 4 , LiAsF 6 , LiSbF 6 , LiClO 4 , Li(R f1 SO 3 ), LiN(R f1 SO 2 ) 2 , LiN(FSO 2 ) 2 , or LiN(R f1 SO 2 ) (R f2 SO 2 ) is preferred, and LiPF 6 , LiBF 4 , LiN(R f1 SO 2 ) 2 , LiN(FSO 2 ) 2 or LiN(R f1 SO 2 )(R f2 SO 2 ) is more preferred. Here, R f1 and R f2 each represent a perfluoroalkyl group, and preferably have 1 to 6 carbon atoms.
Note that the electrolytes used in the non-aqueous electrolyte may be used alone or in any combination of two or more.
　非水電解液における電解質（好ましくは周期律表第１族又は第２族に属する金属のイオン若しくはその金属塩）の塩濃度は非水電解液の使用目的により適宜選択されるが、一般的には非水電解液の全質量中１０～５０質量％であり、好ましくは１５～３０質量％である。モル濃度としては０．５～１．５Ｍが好ましい。なお、イオンの濃度として評価するときには、その好適に適用される金属塩換算で算出すればよい。 The salt concentration of the electrolyte (preferably ions of metals belonging to Group 1 or Group 2 of the periodic table or metal salts thereof) in the non-aqueous electrolyte is selected as appropriate depending on the purpose of use of the non-aqueous electrolyte, but generally is 10 to 50% by mass, preferably 15 to 30% by mass, based on the total mass of the nonaqueous electrolyte. The molar concentration is preferably 0.5 to 1.5M. Note that when evaluating the concentration of ions, it may be calculated in terms of metal salts that are suitably applied.
（非水溶媒）
　非水電解液は、非水溶媒を含有する。
　非水溶媒としては、非プロトン性有機溶媒が好ましく、中でも炭素数が２～１０の非プロトン性有機溶媒がより好ましい。
　このような非水溶媒としては、鎖状若しくは環状のカーボネート化合物、ラクトン化合物、鎖状若しくは環状のエーテル化合物、エステル化合物、ニトリル化合物、アミド化合物、オキサゾリジノン化合物、ニトロ化合物、鎖状又は環状のスルホン若しくはスルホキシド化合物、リン酸エステル化合物が挙げられる。
　なお、エーテル結合、カルボニル結合、エステル結合又はカーボネート結合を有する化合物が好ましい。これらの化合物は置換基を有していてもよく、有していてもよい置換基としては、例えば上述の置換基群Ｔから選ばれる置換基が挙げられる。 (Non-aqueous solvent)
The non-aqueous electrolyte contains a non-aqueous solvent.
As the non-aqueous solvent, aprotic organic solvents are preferred, and aprotic organic solvents having 2 to 10 carbon atoms are particularly preferred.
Such nonaqueous solvents include chain or cyclic carbonate compounds, lactone compounds, chain or cyclic ether compounds, ester compounds, nitrile compounds, amide compounds, oxazolidinone compounds, nitro compounds, chain or cyclic sulfones, or Examples include sulfoxide compounds and phosphate ester compounds.
Note that compounds having an ether bond, a carbonyl bond, an ester bond, or a carbonate bond are preferred. These compounds may have a substituent, and examples of the substituent that may be included include substituents selected from the above-mentioned substituent group T.
　非水溶媒としては、例えば、エチレンカーボネート、フッ化エチレンカーボネート、ビニレンカーボネート、プロピレンカーボネート、ブチレンカーボネート、ジメチルカーボネート、ジエチルカーボネート、エチルメチルカーボネート、メチルプロピルカーボネート、γ－ブチロラクトン、γ－バレロラクトン、１，２－ジメトキシエタン、テトラヒドロフラン、２－メチルテトラヒドロフラン、テトラヒドロピラン、１，３－ジオキソラン、４－メチル－１，３－ジオキソラン、１，３－ジオキサン、１，４－ジオキサン、酢酸メチル、酢酸エチル、プロピオン酸メチル、プロピオン酸エチル、酪酸メチル、イソ酪酸メチル、トリメチル酢酸メチル、トリメチル酢酸エチル、アセトニトリル、グルタロニトリル、アジポニトリル、メトキシアセトニトリル、３－メトキシプロピオニトリル、Ｎ，Ｎ－ジメチルホルムアミド、Ｎ－メチルピロリジノン、Ｎ－メチルオキサゾリジノン、Ｎ，Ｎ’－ジメチルイミダゾリジノン、ニトロメタン、ニトロエタン、スルホラン、リン酸トリメチル、ジメチルスルホキシドあるいはジメチルスルホキシドリン酸等が挙げられる。これらは、１種単独で用いても２種以上を併用してもよい。中でも、エチレンカーボネート、プロピレンカーボネート、ジメチルカーボネート、ジエチルカーボネート、エチルメチルカーボネート、及びγ－ブチロラクトンのうちの少なくとも１種が好ましく、エチレンカーボネート又はプロピレンカーボネート等の高粘度（高誘電率）溶媒（例えば、比誘電率ε≧３０）とジメチルカーボネート、エチルメチルカーボネート又はジエチルカーボネート等の低粘度溶媒（例えば、粘度≦１ｍＰａ・ｓ）との組み合わせがより好ましい。このような組み合わせの混合溶媒とすることで、電解質塩の解離性及びイオンの移動度が向上する。
　なお、本発明に用いられる非水溶媒は、これらに限定されるものではない。 Examples of the nonaqueous solvent include ethylene carbonate, fluorinated ethylene carbonate, vinylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, methylpropyl carbonate, γ-butyrolactone, γ-valerolactone, 1, 2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,3-dioxane, 1,4-dioxane, methyl acetate, ethyl acetate, propion Methyl acid, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethyl acetate, ethyl trimethyl acetate, acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, N,N-dimethylformamide, N-methyl Examples include pyrrolidinone, N-methyloxazolidinone, N,N'-dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, trimethyl phosphate, dimethyl sulfoxide, and dimethyl sulfoxide phosphoric acid. These may be used alone or in combination of two or more. Among them, at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, and γ-butyrolactone is preferable, and high viscosity (high dielectric constant) solvents such as ethylene carbonate or propylene carbonate (for example, A combination of a dielectric constant ε≧30) and a low viscosity solvent (for example, viscosity≦1 mPa·s) such as dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate is more preferable. By using such a combination of mixed solvents, the dissociation property of the electrolyte salt and the mobility of ions are improved.
Note that the nonaqueous solvent used in the present invention is not limited to these.
　本発明の二次電池は、例えば、ノートパソコン、ペン入力パソコン、モバイルパソコン、電子ブックプレーヤー、携帯電話、コードレスフォン子機、ページャー、ハンディーターミナル、携帯ファックス、携帯コピー、携帯プリンター、ヘッドフォンステレオ、ビデオムービー、液晶テレビ、ハンディークリーナー、ポータブルＣＤ、ミニディスク、電気シェーバー、トランシーバー、電子手帳、電卓、携帯テープレコーダー、ラジオ、バックアップ電源、メモリーカード等の電子機器に搭載することができる。また、民生用として、自動車、電動車両、モーター、照明器具、玩具、ゲーム機器、ロードコンディショナー、時計、ストロボ、カメラ、医療機器（ペースメーカー、補聴器、肩もみ機等）等に搭載することができる。更に、各種軍需用、及び、宇宙用として用いることができる。また、太陽電池と組み合わせることもできる。 The secondary battery of the present invention can be used, for example, in a notebook computer, a pen input computer, a mobile computer, an e-book player, a mobile phone, a cordless phone, a pager, a handy terminal, a mobile fax machine, a mobile copier, a mobile printer, a headphone stereo, a video It can be installed in electronic devices such as movies, LCD TVs, handy cleaners, portable CDs, mini discs, electric shavers, transceivers, electronic notebooks, calculators, portable tape recorders, radios, backup power sources, and memory cards. Furthermore, for consumer use, it can be installed in automobiles, electric vehicles, motors, lighting equipment, toys, game equipment, road conditioners, watches, strobes, cameras, medical equipment (pacemakers, hearing aids, shoulder massagers, etc.), etc. Furthermore, it can be used for various military purposes and for space purposes. It can also be combined with solar cells.
　実施例に基づき本発明について更に詳細に説明する。なお、本発明は本発明で規定すること以外は、これらの実施例により限定して解釈されるものではない。また、室温とは２７℃を意味する。組成比、配合量比、含有量については、特段の断りのない限り、質量基準を意味する。 The present invention will be explained in more detail based on Examples. Note that the present invention is not to be construed as being limited by these Examples other than what is specified in the present invention. Moreover, room temperature means 27°C. The composition ratio, blending ratio, and content are based on mass unless otherwise specified.
［水溶性高分子（Ｘ）の合成］
　後記表１に記載するバインダー組成物１～６及びｃ１～ｃ９の調製に用いる水溶性高分子（Ｘ）を以下のようにして合成した。 [Synthesis of water-soluble polymer (X)]
Water-soluble polymers (X) used in the preparation of binder compositions 1 to 6 and c1 to c9 listed in Table 1 below were synthesized as follows.
（バインダー組成物１～４、ｃ３、ｃ４、ｃ８及びｃ９に用いる水溶性高分子（Ｘ））
　アクリルアミド（富士フイルム和光純薬社製）７５．０ｇ、蒸留水７５．０ｇ、ＶＡ－０５７（商品名、富士フイルム和光純薬社製、カルボキシ基含有水溶性アゾ重合開始剤）０．５３ｇを室温で、撹拌、混合し、溶液Ｉを調製した。
　還流冷却管、ガス導入コックを付した１Ｌ三口フラスコに、蒸留水３３７．５ｇを加えた。流速２００ｍＬ／ｍｉｎにて窒素ガスを６０分間導入した後に、７５℃に昇温した。上記調製した溶液Ｉを、上記１Ｌ三口フラスコ中の蒸留水に１時間かけて滴下した。滴下完了後、７５℃で３時間撹拌を続けた。室温まで冷却し、バインダー組成物１～４、ｃ３、ｃ４、ｃ８及びｃ９に用いる水溶性高分子（Ｘ）（ＰＡＡｍ）の水溶液を得た。固形分濃度は１４．０％、重量平均分子量は３４７０００であった。 (Water-soluble polymer (X) used in binder compositions 1 to 4, c3, c4, c8 and c9)
75.0 g of acrylamide (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.), 75.0 g of distilled water, and 0.53 g of VA-057 (trade name, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., water-soluble azo polymerization initiator containing a carboxyl group) at room temperature. Solution I was prepared by stirring and mixing.
337.5 g of distilled water was added to a 1 L three-neck flask equipped with a reflux condenser and a gas introduction cock. After introducing nitrogen gas for 60 minutes at a flow rate of 200 mL/min, the temperature was raised to 75°C. The solution I prepared above was added dropwise to the distilled water in the 1 L three-necked flask over 1 hour. After completion of the dropwise addition, stirring was continued at 75° C. for 3 hours. It was cooled to room temperature to obtain an aqueous solution of water-soluble polymer (X) (PAAm) used in binder compositions 1 to 4, c3, c4, c8, and c9. The solid content concentration was 14.0%, and the weight average molecular weight was 347,000.
（バインダー組成物５の調製に用いる水溶性高分子（Ｘ））
　上記水溶性高分子（Ｘ）（ＰＡＡｍ）の合成において、アクリルアミドに代えてアクリルアミド、Ｎ－（２－ヒドロキシエチル）アクリルアミド及びｔｅｒｔ－ブチルアクリルアミドを、アクリルアミド：Ｎ－（２－ヒドロキシエチル）アクリルアミド：ｔｅｒｔ－ブチルアクリルアミド＝８５：１０：５（質量比）で用いたこと以外は、水溶性高分子（Ｘ）（ＰＡＡｍ）の合成と同様にして、後記表１に記載するバインダー組成物５の調製に用いる水溶性高分子（Ｘ）（ＰＡＡｍ－ＨＥＡＡ－ＴＢＡＡｍ）の水溶液を得た。固形分濃度は１１．３質量％、重量平均分子量は７２４２６９であった。 (Water-soluble polymer (X) used for preparing binder composition 5)
In the synthesis of the above water-soluble polymer (X) (PAAm), acrylamide, N-(2-hydroxyethyl)acrylamide and tert-butylacrylamide were used instead of acrylamide, acrylamide: N-(2-hydroxyethyl)acrylamide: tert-butylacrylamide. - Butylacrylamide = 85:10:5 (mass ratio) was used in the preparation of binder composition 5 described in Table 1 in the same manner as the synthesis of water-soluble polymer (X) (PAAm). An aqueous solution of water-soluble polymer (X) (PAAm-HEAA-TBAAm) to be used was obtained. The solid content concentration was 11.3% by mass, and the weight average molecular weight was 724,269.
（バインダー組成物６の調製に用いる水溶性高分子（Ｘ））
　上記水溶性高分子（Ｘ）（ＰＡＡｍ）の合成において、アクリルアミドに代えてアクリルアミド及びアクリロニトリルを、アクリルアミド：アクリロニトリル＝８０：２０（質量比）で用いたこと以外は、水溶性高分子（Ｘ）（ＰＡＡｍ）の合成と同様にして、後記表１に記載するバインダー組成物６の調製に用いる水溶性高分子（Ｘ）（ＰＡＡｍ－ＡＮ）の水溶液を得た。固形分濃度は１３．３質量％、重量平均分子量は１８９３７３であった。 (Water-soluble polymer (X) used for preparing binder composition 6)
In the synthesis of the water-soluble polymer (X) (PAAm) above, the water-soluble polymer (X) ( In the same manner as in the synthesis of PAAm), an aqueous solution of water-soluble polymer (X) (PAAm-AN) used in the preparation of binder composition 6 shown in Table 1 below was obtained. The solid content concentration was 13.3% by mass, and the weight average molecular weight was 189,373.
（バインダー組成物ｃ６の調製に用いる水溶性高分子）
　後記表１に記載するバインダー組成物ｃ６の調製に用いる水溶性高分子の水溶液として、ＣＬＰＡ－Ｃ０７（商品名、アクリル酸と疎水性モノマーからなる架橋型共重合バインダー、富士フイルム和光純薬社製）を用いた。固形分濃度は１０．０質量％に調節した。ＣＬＰＡ－Ｃ０７は、一般式（Ｂ－２）で表される構成成分を有さない高分子である。 (Water-soluble polymer used for preparing binder composition c6)
CLPA-C07 (trade name, crosslinked copolymer binder consisting of acrylic acid and a hydrophobic monomer, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. ) was used. The solid content concentration was adjusted to 10.0% by mass. CLPA-C07 is a polymer that does not have a constituent represented by general formula (B-2).
（バインダー組成物ｃ７の調製に用いる水溶性高分子）
　後記表１に記載するバインダー組成物ｃ７の調製に用いる水溶性高分子の水溶液として、ＣＬＰＡ－Ｗ１１（商品名、架橋型ポリアクリル酸バインダー、富士フイルム和光純薬社製）を用いた。固形分濃度は１０．３質量％に調節した。ＣＬＰＡ－Ｗ１１は、一般式（Ｂ－２）で表される構成成分を有さない高分子である。
　便宜上、これら水溶性高分子（ＣＬＰＡ－Ｃ０７及びＣＬＰＡ－Ｗ１１）を、後記表１の「水溶性高分子（Ｘ）」欄に示す。 (Water-soluble polymer used for preparing binder composition c7)
CLPA-W11 (trade name, cross-linked polyacrylic acid binder, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was used as an aqueous solution of a water-soluble polymer used in the preparation of binder composition c7 listed in Table 1 below. The solid content concentration was adjusted to 10.3% by mass. CLPA-W11 is a polymer that does not have a constituent represented by general formula (B-2).
For convenience, these water-soluble polymers (CLPA-C07 and CLPA-W11) are shown in the "Water-soluble polymer (X)" column of Table 1 below.
　上記水溶性高分子は、いずれも、２０℃において水に対して１００ｇ／Ｌ－Ｈ２Ｏ以上の溶解度を示した。 All of the above water-soluble polymers exhibited a solubility in water of 100 g/L-H 2 O or more at 20°C.
［バインダー組成物の調製］
（バインダー組成物１）
　後記表１に記載するバインダー組成物１を以下のようにして調製した。
　具体的には、上記で得られた水溶性高分子（Ｘ）（ＰＡＡｍ）の水溶液　１．４５ｇ（固形分量０．２０ｇ）に、水溶性化合物（Ｙ）としてカルボキシメチルセルロース（ＣＭＣ）の水溶液１．６８ｇ（固形分量０．０８ｇ）、重合体粒子（Ｚ）として重合体粒子１（特開２０１２－２１２５３７号公報の段落番号００３８に記載の共重合体ラテックス１の作製例に従って合成したもの）　０．４１ｇ（固形分量０．２０ｇ）を加え、あわとり練太郎（商品名、ＴＨＩＮＫＹ社製）を用いて２０００ｒｐｍで２１分間分散することにより、バインダー組成物１を得た。バインダー組成物１の固形分濃度は、１４質量％であった。 [Preparation of binder composition]
(Binder composition 1)
Binder Composition 1 shown in Table 1 below was prepared as follows.
Specifically, 1.45 g (solid content 0.20 g) of the aqueous solution of the water-soluble polymer (X) (PAAm) obtained above was added with 1.5 g of an aqueous solution of carboxymethyl cellulose (CMC) as the water-soluble compound (Y). 68 g (solid content 0.08 g), polymer particles 1 as polymer particles (Z) (synthesized according to the production example of copolymer latex 1 described in paragraph number 0038 of JP-A-2012-212537) 0. Binder Composition 1 was obtained by adding 41 g (solid content: 0.20 g) and dispersing for 21 minutes at 2000 rpm using Awatori Rentaro (trade name, manufactured by THINKY). The solid content concentration of Binder Composition 1 was 14% by mass.
（バインダー組成物２～６及びｃ１～ｃ９）
　バインダー組成物１の調製において、後記表１に記載する成分及び含有量比（質量比）を採用したこと以外は、バインダー組成物１と同様にして、バインダー組成物２～６及びｃ１～ｃ９を調製した。
　バインダー組成物ｃ９に用いた水ガラスは、重合体粒子ではないが、便宜上、後記表１の「重合体粒子（Ｚ）」欄に示す。 (Binder compositions 2-6 and c1-c9)
In preparing binder composition 1, binder compositions 2 to 6 and c1 to c9 were prepared in the same manner as binder composition 1, except that the components and content ratios (mass ratios) listed in Table 1 below were adopted. Prepared.
Although the water glass used in binder composition c9 is not a polymer particle, it is shown in the "Polymer particle (Z)" column in Table 1 below for convenience.
　各バインダー組成物について、上記三成分の含有量の質量比（水溶性高分子（Ｘ）：水溶性化合物（Ｙ）：重合体粒子（Ｚ））を後記表１の「（Ｘ）（Ｙ）（Ｚ）の質量比」欄に示す。質量比は、各成分の固形分量から算出した。 For each binder composition, the mass ratio of the contents of the above three components (water-soluble polymer (X): water-soluble compound (Y): polymer particles (Z)) is determined as "(X) (Y)" in Table 1 below. (Z) mass ratio” column. The mass ratio was calculated from the solid content of each component.
［バインダー組成物の引張弾性率の算出］
　剥離性のポリエチレンテレフタレート（ＰＥＴ）フィルムに、上記で得られた各バインダー組成物を塗布して、乾燥させた。ＰＥＴフィルムから、バインダー組成物の塗布膜を剥離して試験片（縦５ｃｍ、横０．５ｃｍ、膜厚０．１０ｍｍ）を得た。試験片の長さ方向において、試験片の一方の端から１ｃｍの位置及び他方の端から１ｃｍの位置をそれぞれ治具に固定し、引張試験機（商品名：ＦＧＳ－ＴＶ、日本電産シンポ社製）を用いて引張試験を行った。なお、この試験は２３℃、引張速度５ｍｍ／分で行った。荷重に対する変位を測定した結果から得られる応力－ひずみ曲線の弾性領域の平均値から引張弾性率を算出した。得られた引張弾性率を後記表１に示す。 [Calculation of tensile modulus of binder composition]
Each of the binder compositions obtained above was applied to a releasable polyethylene terephthalate (PET) film and dried. The coated film of the binder composition was peeled off from the PET film to obtain a test piece (5 cm long, 0.5 cm wide, 0.10 mm thick). In the longitudinal direction of the test piece, the test piece was fixed to a jig at a position 1 cm from one end and a position 1 cm from the other end. A tensile test was conducted using a Note that this test was conducted at 23° C. and a tensile speed of 5 mm/min. The tensile modulus was calculated from the average value of the elastic region of the stress-strain curve obtained from the results of measuring the displacement with respect to the load. The obtained tensile modulus is shown in Table 1 below.
［電極用組成物Ｅ１～Ｅ６及びｃＥ１～ｃＥ９の調製］
　上記各バインダー組成物の成分を含有し、かつ高容量活物質としてカーボンコートされた酸化ケイ素を含む電極用組成物を調製した。
　得られた各電極用組成物は、特定の平均粒径及び比表面積の、カーボンコートされた酸化ケイ素と黒鉛とアセチレンブラックとを、特定量で含有した、＜貯蔵弾性率特性１＞の判定に用いるスラリーに相当する。後記表１においては、各バインダー組成物の成分を「バインダー組成物」欄に、バインダー組成物の成分以外の各電極用組成物Ｅ１～Ｅ６及びｃＥ１～ｃＥ９の成分を「電極スラリーＡ」欄に記載する。表１における記載を省略するが、電極用組成物Ｅ１～Ｅ６及びｃＥ１～ｃＥ９は、それぞれバインダー組成物１～６及びｃ１～ｃ９の成分を含む電極用組成物である。 [Preparation of electrode compositions E1 to E6 and cE1 to cE9]
Electrode compositions containing the components of each of the binder compositions described above and carbon-coated silicon oxide as a high-capacity active material were prepared.
Each of the obtained electrode compositions contained specific amounts of carbon-coated silicon oxide, graphite, and acetylene black with a specific average particle size and specific surface area, and was tested for <storage modulus property 1>. This corresponds to the slurry used. In Table 1 below, the components of each binder composition are listed in the "Binder Composition" column, and the components of each electrode composition E1 to E6 and cE1 to cE9 other than the components of the binder composition are listed in the "Electrode Slurry A" column. Describe it. Although descriptions in Table 1 are omitted, electrode compositions E1 to E6 and cE1 to cE9 are electrode compositions containing the components of binder compositions 1 to 6 and c1 to c9, respectively.
（電極用組成物Ｅ１）
　６０ｍＬの軟膏容器（馬野化学社製）に、活物質としてＳｉＯＣ（カーボンコートされた酸化ケイ素（炭素元素の含有量の割合１．３質量％）、大阪チタニウムテクノロジーズ社製、グレード：ＳｉＯ　ＮＣ　５μｍ、平均粒径：５μｍ、比表面積：２．６ｍ２／ｇ）１．７８ｇ及び黒鉛（商品名：ＭＡＧ－Ｄ、昭和電工マテリアルズ社製、平均粒径：２１μｍ、比表面積：４ｍ２／ｇ）７．１２ｇ、導電助剤としてアセチレンブラック（商品名：デンカブラック、デンカ社製、粉状品、平均粒径：３５ｎｍ、比表面積：６８ｍ２／ｇ）０．６０ｇ、上記で得られた水溶性高分子（Ｘ）の水溶液　１．４５ｇ（固形分量０．２０ｇ）、水溶性化合物（Ｙ）としてカルボキシメチルセルロース（ＣＭＣ）１．６８ｇ（固形分量０．０８ｇ）、蒸留水３．８ｇを加え、あわとり練太郎（商品名、ＴＨＩＮＫＹ社製）を用いて２０００ｒｐｍで６分間分散した。分散した液に蒸留水を更に１．８ｇ加え、あわとり練太郎（商品名、ＴＨＩＮＫＹ社製）を用いて２０００ｒｐｍで１２分間分散した。更に、分散した液に重合体粒子として重合体粒子１（特開２０１２－２１２５３７号公報の段落番号００３８に記載の共重合体ラテックス１の作製例に従って合成したもの）０．４１ｇ（固形分量０．２０ｇ）を加え、あわとり練太郎（商品名、ＴＨＩＮＫＹ社製）を用いて２０００ｒｐｍで３分間分散し、電極用組成物Ｅ１（スラリー）を得た。この電極用組成物Ｅ１は、全固形分１００質量部中に、カーボンコートされた酸化ケイ素を１７．８質量部、黒鉛を７１．２質量部、アセチレンブラックを６質量部、バインダー成分（水溶性高分子（Ｘ）、水溶性化合物（Ｙ）及び重合体粒子（Ｚ））を固形分として５質量部含有しており、かつスラリー中の全固形分量は５２質量％とした。なお、上記電極用組成物Ｅ１は、水溶性高分子（Ｘ）、水溶性化合物（Ｙ）、重合体分子、及び蒸留水等を別々に添加しているが、バインダー組成物１に、活物質及び導電助剤を添加して、水分を制御して、スラリー中の全固形分量を５２質量％としたものと同等である。
　電極用組成物Ｅ１に含有されるバインダー成分（水溶性高分子（Ｘ）、水溶性化合物（Ｙ）及び重合体粒子（Ｚ））は、上記バインダー組成物１中のバインダー成分と種類及び質量比は同様である。 (Electrode composition E1)
In a 60 mL ointment container (manufactured by Umano Chemical Co., Ltd.), SiOC (carbon-coated silicon oxide (carbon element content ratio 1.3% by mass)) as an active material, manufactured by Osaka Titanium Technologies, grade: SiO NC 5 μm, Average particle size: 5 μm, specific surface area: 2.6 m 2 /g) 1.78 g and graphite (trade name: MAG-D, manufactured by Showa Denko Materials Co., Ltd., average particle size: 21 μm, specific surface area: 4 m 2 /g) 7.12 g, 0.60 g of acetylene black (trade name: Denka Black, manufactured by Denka Co., Ltd., powder product, average particle size: 35 nm, specific surface area: 68 m 2 /g) as a conductive aid, the water-soluble material obtained above Add 1.45 g (solid content 0.20 g) of an aqueous solution of polymer (X), 1.68 g (solid content 0.08 g) of carboxymethyl cellulose (CMC) as a water-soluble compound (Y), and 3.8 g of distilled water, Dispersion was performed at 2000 rpm for 6 minutes using Tori Rentaro (trade name, manufactured by THINKY). Another 1.8 g of distilled water was added to the dispersed liquid, and the mixture was dispersed at 2000 rpm for 12 minutes using Awatori Rentaro (trade name, manufactured by THINKY). Further, 0.41 g of polymer particles 1 (synthesized according to the example of producing copolymer latex 1 described in paragraph number 0038 of JP-A-2012-212537) (solid content 0.41 g) was added to the dispersed liquid as polymer particles. 20 g) was added thereto and dispersed for 3 minutes at 2000 rpm using Awatori Rentaro (trade name, manufactured by THINKY) to obtain electrode composition E1 (slurry). This electrode composition E1 contains 100 parts by mass of total solids, 17.8 parts by mass of carbon-coated silicon oxide, 71.2 parts by mass of graphite, 6 parts by mass of acetylene black, and a binder component (water-soluble The slurry contained 5 parts by mass of solids (polymer (X), water-soluble compound (Y), and polymer particles (Z)), and the total solid content in the slurry was 52% by mass. Note that in the electrode composition E1, the water-soluble polymer (X), the water-soluble compound (Y), the polymer molecule, distilled water, etc. are separately added, but the active material is added to the binder composition 1. This is equivalent to adding a conductive additive and controlling the moisture content so that the total solid content in the slurry is 52% by mass.
The binder components (water-soluble polymer (X), water-soluble compound (Y), and polymer particles (Z)) contained in electrode composition E1 have the same type and mass ratio as the binder component in binder composition 1 above. are similar.
（電極用組成物Ｅ２～Ｅ６及びｃＥ１～ｃＥ９）
　電極用組成物Ｅ１の調製において、バインダー成分（水溶性高分子（Ｘ）、水溶性化合物（Ｙ）及び重合体粒子（Ｚ））の組成が後記表１に記載の各バインダー組成物と同様になるように変更したこと以外は、電極用組成物Ｅ１の調製と同様にして、電極用組成物Ｅ２～Ｅ６及びｃＥ１～ｃＥ９を調製した。 (Electrode compositions E2 to E6 and cE1 to cE9)
In the preparation of electrode composition E1, the composition of the binder components (water-soluble polymer (X), water-soluble compound (Y), and polymer particles (Z)) was the same as in each binder composition listed in Table 1 below. Electrode compositions E2 to E6 and cE1 to cE9 were prepared in the same manner as in the preparation of electrode composition E1, except for the following changes.
［電極用組成物のひずみ分散測定、貯蔵弾性率の差の算出１］
　上記で得られた各電極用組成物（固形分量５２質量％）を１ｍＬ用いて、レオメータ（モジュラーコンパクトレオメータＭＣＲ１０２（商品名）、アントンパール社製）で、２５℃、１０ｒａｄ／ｓ、レオメータ治具ＰＰ５０の条件でひずみ分散測定を行った。得られたせん断ひずみ０．０１％での貯蔵弾性率とせん断ひずみ１０％での貯蔵弾性率とを読み取り、これらの差を算出した。
　結果を後記表１に示す。
　得られた貯蔵弾性率の差に基づいて、各バインダー組成物の＜貯蔵弾性率特性１＞の充足性を判定することができる。 [Strain dispersion measurement of electrode composition, calculation of difference in storage modulus 1]
Using 1 mL of each electrode composition (solid content 52% by mass) obtained above, a rheometer (Modular Compact Rheometer MCR102 (trade name), manufactured by Anton Paar) was used at 25°C, 10 rad/s, and a rheometer jig. Strain dispersion measurement was performed under the condition of PP50. The obtained storage elastic modulus at a shear strain of 0.01% and the storage elastic modulus at a shear strain of 10% were read, and the difference between them was calculated.
The results are shown in Table 1 below.
Based on the difference in storage modulus obtained, the sufficiency of <storage modulus characteristic 1> of each binder composition can be determined.
［電極用組成物Ｅ７～Ｅ１２及びｃＥ１０～ｃＥ１６の調製］
　上記各バインダー組成物の成分を含有し、かつ高容量活物質としてカーボンコート及びリチウムドープの両方が施された酸化ケイ素を含む各電極用組成物を以下のようにして調製した。
　なお、得られた各電極用組成物は、カーボンコート及び金属元素のドープ（リチウムドープ）の両方が施された酸化ケイ素を用いているので、＜貯蔵弾性率特性１＞の判定に用いるスラリーに相当するものではない。 [Preparation of electrode compositions E7 to E12 and cE10 to cE16]
Each electrode composition containing the components of each of the binder compositions described above and containing silicon oxide coated with both carbon and doped with lithium as a high-capacity active material was prepared as follows.
In addition, since each of the obtained electrode compositions uses silicon oxide coated with both a carbon coat and a metal element dope (lithium dope), the slurry used for determining <storage modulus characteristic 1> It is not equivalent.
１．カーボンコート及びリチウムドープの両方が施された酸化ケイ素の作製
　特開２０２２－１２１５８２号公報の実施例１－１に記載の方法と同様にして、カーボンコート及びリチウムドープの両方が施された酸化ケイ素を作製した。具体的には以下のようにして行った。
（ｉ）カーボンコートされた酸化ケイ素の作製
　金属ケイ素と二酸化ケイ素を混合した原料（気化出発材）を反応炉へ設置し、１０Ｐａの真空度の雰囲気中で気化させたものを吸着板上に堆積させ、十分に冷却した後、堆積物（酸化ケイ素）を取出しボールミルで粉砕した。粒径を調整した後、熱ＣＶＤ（ｔｈｅｍａｌ　ｃｈｅｍｉｃａｌ　ｖａｐｏｒ　ｄｅｐｏｓｉｔｉｏｎ）を行うことでカーボンコートを形成した。熱ＣＶＤの際には、粉砕した酸化ケイ素を、窒化珪素製トレイに仕込んだ後、雰囲気を保持できる処理炉内に静置した。次にアルゴンガスを流入し、処理炉内をアルゴン置換した後、メタン－アルゴン混合ガスを２ＮＬ／ｍｉｎ流入しつつ３００℃／ｈｒの昇温速度で昇温し、６００～１，１００℃の温度で、３～１０時間保持することにより熱ＣＶＤを施し、カーボンコートされた酸化ケイ素（ＳｉＯＣ）を得た。保持終了後、降温を開始し、室温到達後、粉末を回収した。
（ii）カーボンコートされた酸化ケイ素へのリチウムドープ処理
　カーボンコートされた酸化ケイ素に対して酸化還元法によりリチウムをドープし改質を行った。
　まず、カーボンコートされた酸化ケイ素を、リチウム片とナフタレンとをテトラヒドロフラン（以下、ＴＨＦと呼称する）に溶解させた溶液（溶液Ａ）に浸漬した。この溶液Ａは、具体的には、ＴＨＦ溶媒にナフタレンを０．２ｍｏｌ／Ｌの濃度で溶解させたのちに、このＴＨＦ溶媒とナフタレンとの混合液に対して１０質量％の質量分のリチウム片を加えることで作製した。また、カーボンコートされた酸化ケイ素を浸漬する際の溶液Ａの温度は２０℃とし、浸漬時間は２０時間とした。その後、固形分を濾取した。以上の処理によりカーボンコートされた酸化ケイ素にリチウムをドープした。得られた固形分をアルゴン雰囲気下６００℃で２４時間熱処理を行いＬｉ化合物の安定化を行った。このようにして、カーボンコートされた酸化ケイ素の改質を行い、カーボンコート及びリチウムドープの両方が施された酸化ケイ素（ＬｉＳｉＯＣ）を得た。
　なお、炭素元素の含有量の割合は３質量％、ＬｉＳｉＯＣ粒子の平均粒径（体積基準のメジアン径Ｄ５０）は６．７μｍであった。 1. Production of silicon oxide coated with both carbon coat and lithium dope Silicon oxide coated with both carbon coat and lithium dope in the same manner as the method described in Example 1-1 of JP-A-2022-121582 was created. Specifically, it was performed as follows.
(i) Preparation of carbon-coated silicon oxide A raw material (vaporization starting material) containing metallic silicon and silicon dioxide is placed in a reaction furnace, vaporized in a vacuum atmosphere of 10 Pa, and deposited on an adsorption plate. After cooling sufficiently, the deposit (silicon oxide) was taken out and ground in a ball mill. After adjusting the particle size, a carbon coat was formed by thermal CVD (thermal chemical vapor deposition). During thermal CVD, pulverized silicon oxide was placed in a silicon nitride tray, and then placed in a processing furnace capable of maintaining an atmosphere. Next, argon gas was introduced to replace the inside of the processing furnace with argon, and then the temperature was raised at a rate of 300°C/hr while a methane-argon mixed gas was introduced at a rate of 2NL/min until the temperature reached 600 to 1,100°C. Then, thermal CVD was performed by holding the sample for 3 to 10 hours to obtain carbon-coated silicon oxide (SiOC). After the holding was completed, the temperature was started to decrease, and after reaching room temperature, the powder was collected.
(ii) Lithium doping treatment to carbon-coated silicon oxide Carbon-coated silicon oxide was doped with lithium by a redox method to perform modification.
First, carbon-coated silicon oxide was immersed in a solution (solution A) in which lithium pieces and naphthalene were dissolved in tetrahydrofuran (hereinafter referred to as THF). Specifically, this solution A is prepared by dissolving naphthalene in a THF solvent at a concentration of 0.2 mol/L, and then dissolving lithium pieces in a mass amount of 10% by mass with respect to the mixed solution of the THF solvent and naphthalene. It was created by adding. Further, the temperature of solution A when immersing the carbon-coated silicon oxide was 20° C., and the immersion time was 20 hours. Thereafter, the solid content was collected by filtration. Through the above treatment, the carbon-coated silicon oxide was doped with lithium. The obtained solid content was heat treated at 600° C. for 24 hours in an argon atmosphere to stabilize the Li compound. In this way, the carbon-coated silicon oxide was modified to obtain silicon oxide (LiSiOC) that was both carbon-coated and lithium-doped.
Note that the content ratio of carbon element was 3% by mass, and the average particle size (volume-based median diameter D50) of the LiSiOC particles was 6.7 μm.
２．電極用組成物の調製
　電極用組成物Ｅ１の調製において、カーボンコートされた酸化ケイ素を上記カーボンコート及びリチウムドープの両方が施された酸化ケイ素（ＬｉＳｉＯＣ）に変更したこと、及びバインダー成分（水溶性高分子（Ｘ）、水溶性化合物（Ｙ）及び重合体粒子（Ｚ））の組成が後記表１に記載のバインダー組成物と同様になるように変更したこと以外は、電極用組成物Ｅ１の調製と同様にして、電極用組成物Ｅ７～Ｅ１２及びｃＥ１０～ｃＥ１６を調製した。後記表２の「対応するバインダー組成物Ｎｏ．」欄に対応するバインダー組成物を示す。 2. Preparation of Electrode Composition In the preparation of electrode composition E1, the carbon-coated silicon oxide was changed to the carbon-coated and lithium-doped silicon oxide (LiSiOC), and the binder component (water-soluble Electrode composition E1 except that the compositions of polymer (X), water-soluble compound (Y) and polymer particles (Z) were changed to be the same as the binder composition listed in Table 1 below. Electrode compositions E7 to E12 and cE10 to cE16 were prepared in the same manner as in the preparation. The corresponding binder compositions are shown in the "Corresponding Binder Composition No." column of Table 2 below.
［電極用組成物のひずみ分散測定、貯蔵弾性率の差の算出２］
　電極用組成物Ｅ７～１２及びｃＥ１０～ｃＥ１６についても、ひずみ分散測定を行い、せん断ひずみ０．０１％での貯蔵弾性率とせん断ひずみ１０％での貯蔵弾性率とを読み取り、これらの差を算出した。測定は、スラリーとして各電極用組成物Ｅ７～Ｅ１２及びｃＥ１０～ｃＥ１６を用いた以外は、上記［電極用組成物のひずみ分散測定、貯蔵弾性率の差の算出１］と同様にして行った。結果を後記表２に示す。
　なお、後記表２には、電極用組成物Ｅ１～Ｅ６及びｃＥ１～ｃＥ９についての測定結果もあわせて示した。 [Strain dispersion measurement of electrode composition, calculation of difference in storage modulus 2]
For electrode compositions E7 to 12 and cE10 to cE16, strain dispersion measurements were also performed, and the storage modulus at a shear strain of 0.01% and the storage modulus at a shear strain of 10% were read, and the difference between them was calculated. did. The measurements were carried out in the same manner as in [Measurement of strain dispersion of electrode compositions, calculation of difference in storage modulus 1], except that each of the electrode compositions E7 to E12 and cE10 to cE16 was used as the slurry. The results are shown in Table 2 below.
Note that Table 2 below also shows the measurement results for electrode compositions E1 to E6 and cE1 to cE9.
［電極用組成物Ｅ１３～Ｅ２４及びｃＥ１７～ｃＥ３０の調製］
　上記各バインダー組成物の成分を含有し、かつ高容量活物質としてカーボンコート及びニッケルドープの両方が施された酸化ケイ素、又はカーボンコート及びチタンドープの両方が施された酸化ケイ素を含む各電極用組成物を以下のようにして調製した。
　なお、得られた各電極用組成物は、カーボンコート及び金属元素のドープ（ニッケルドープ、又はチタンドープ）の両方が施された酸化ケイ素を用いているので、＜貯蔵弾性率特性１＞の判定に用いるスラリーに相当するものではない。 [Preparation of electrode compositions E13 to E24 and cE17 to cE30]
For each electrode containing the components of each of the above binder compositions and containing silicon oxide coated with both carbon coating and nickel doping, or silicon oxide coated with both carbon coating and titanium doping as a high capacity active material. A composition was prepared as follows.
In addition, since each of the obtained electrode compositions uses silicon oxide coated with both a carbon coat and a metal element dope (nickel dope or titanium dope), the determination of <storage modulus characteristic 1> is difficult. It is not equivalent to the slurry used for.
１．カーボンコート及びニッケルドープの両方が施された酸化ケイ素、並びにカーボンコート及びチタンドープの両方が施された酸化ケイ素の作製
　特開２０２１－１５００７７号公報の実施例に記載の負極用粉末材料の作製と同様にして、カーボンコート及びニッケルドープの両方が施された酸化ケイ素（ＮｉＳｉＯＣ）並びにカーボンコート及びチタンドープの両方が施された酸化ケイ素（ＴｉＳｉＯＣ）を作製した。具体的には以下のようにして行った。
（ｉ）Ｓｉ合金の作製
　後記表Ａに示すＳｉ合金組成となるように各原料を秤量した。秤量した各原料を、高周波誘導炉を用いて加熱、溶解し、合金溶湯とした。ガスアトマイズ法により、上記得られた合金溶湯から粉末状のＳｉ合金を作製した。なお、合金溶湯作製時およびガスアトマイズ時の雰囲気はアルゴン雰囲気とした。また、ガスアトマイズ時には、噴霧チャンバ内を棒状に落下する合金溶湯に対して、高圧（４ＭＰａ）のアルゴンガスを噴き付けた。得られた粉末を、篩いを用いて２５μｍ以下に分級したものを、以降のステップでＳｉ合金として用いた。
（ii）メカニカルミリング処理の準備
　ステンレス製のポット中に、金属ボール（サイズ：直径３／８ｉｎｃｈ、材質：ＳＵＪ２（ＪＩＳ（日本工業規格）　Ｇ　４８０５（２０１９）規定の高炭素クロム軸受鋼鋼材ＳＵＪ２））３０個とともに、後記表Ａに示す混合割合となるように、Ｓｉ合金と、金属酸化物としてのＳｉＯ２粉末とを投入した。例えば目的物を１０ｇ作製する場合、Ｓｉ合金９．５ｇとＳｉＯ２粉末０．５ｇとを投入した。投入後、ポット内部の雰囲気をＡｒガスで置換した。
（iii）メカニカルミリング処理
　ポットを遊星ボールミル装置（フリッチュ社製、Ｐ－５／４）にセットし、３００ｒｐｍ、１５０ｈで処理して得られた混合粉末を、以降のステップで金属元素をドープされたケイ素系材料（ニッケルドープされた酸化ケイ素（ＮｉＳｉＯ）又はチタンドープされた酸化ケイ素（ＴｉＳｉＯ））として用いた。
（iv）金属元素をドープされたケイ素系材料へのカーボンコート処理
　金属元素をドープされたケイ素系材料（ＮｉＳｉＯ又はＴｉＳｉＯ）に、熱ＣＶＤを行うことでカーボンコートを形成した。熱ＣＶＤの際には、メカニカルミリング処理後の金属元素をドープされたケイ素系材料を、窒化珪素製トレイに仕込んだ後、雰囲気を保持できる処理炉内に静置した。次にアルゴンガスを流入し、処理炉内をアルゴン置換した後、メタン－アルゴン混合ガスを２ＮＬ／ｍｉｎ流入しつつ３００℃／ｈｒの昇温速度で昇温し、６００～１，１００℃の温度で、３～１０時間保持することにより炭素膜の熱ＣＶＤを施し、カーボンコート及び金属元素のドープの両方が施されたケイ素系材料（カーボンコート及びニッケルドープの両方が施された酸化ケイ素（ＮｉＳｉＯＣ）並びにカーボンコート及びチタンドープの両方が施された酸化ケイ素（ＴｉＳｉＯＣ））を得た。保持終了後、降温を開始し、室温到達後、粉末を回収した。
　なお、炭素元素の含有量の割合は３質量％、ＮｉＳｉＯＣ粒子及びＴｉＳｉＯＣ粒子の平均粒径（体積基準のメジアン径Ｄ５０）は共に７μｍであった。 1. Production of silicon oxide coated with both carbon coat and nickel dope, and silicon oxide coated with both carbon coat and titanium dope Production of powder material for negative electrode described in Examples of JP-A No. 2021-150077 Similarly, silicon oxide (NiSiOC) that was both carbon-coated and doped with nickel and silicon oxide (TiSiOC) that was both carbon-coated and doped with titanium were prepared. Specifically, it was performed as follows.
(i) Production of Si alloy Each raw material was weighed so as to have the Si alloy composition shown in Table A below. Each weighed raw material was heated and melted using a high frequency induction furnace to obtain a molten alloy. A powdered Si alloy was produced from the obtained molten alloy by a gas atomization method. Note that the atmosphere during the preparation of the molten alloy and during gas atomization was an argon atmosphere. Furthermore, during gas atomization, high-pressure (4 MPa) argon gas was sprayed onto the molten alloy falling in a rod shape inside the spray chamber. The obtained powder was classified to 25 μm or less using a sieve and used as a Si alloy in subsequent steps.
(ii) Preparation for mechanical milling process Place a metal ball (size: 3/8 inch in diameter, material: SUJ2 (high carbon chromium bearing steel SUJ2 according to JIS (Japanese Industrial Standards) G 4805 (2019)) in a stainless steel pot. ), Si alloy and SiO 2 powder as a metal oxide were added at a mixing ratio shown in Table A below. For example, when producing 10 g of a target object, 9.5 g of Si alloy and 0.5 g of SiO 2 powder were charged. After charging, the atmosphere inside the pot was replaced with Ar gas.
(iii) Mechanical milling treatment The pot was set in a planetary ball mill device (manufactured by Fritsch, P-5/4), and the mixed powder obtained by processing at 300 rpm for 150 hours was doped with metal elements in the subsequent steps. A silicon-based material (nickel-doped silicon oxide (NiSiO) or titanium-doped silicon oxide (TiSiO)) was used.
(iv) Carbon coating treatment on a silicon-based material doped with a metal element A carbon coat was formed on a silicon-based material (NiSiO or TiSiO) doped with a metal element by performing thermal CVD. During thermal CVD, the silicon-based material doped with a metal element after mechanical milling was placed in a silicon nitride tray, and then placed in a processing furnace capable of maintaining an atmosphere. Next, argon gas was introduced to replace the inside of the processing furnace with argon, and then the temperature was raised at a rate of 300°C/hr while a methane-argon mixed gas was introduced at a rate of 2NL/min until the temperature reached 600 to 1,100°C. The carbon film is then thermally CVDed by holding it for 3 to 10 hours to form a silicon-based material coated with carbon and doped with a metal element (silicon oxide coated with both carbon coat and nickel doped (NiSiOC)). ) and both carbon-coated and titanium-doped silicon oxide (TiSiOC)) were obtained. After the holding was completed, the temperature started to decrease, and after reaching room temperature, the powder was collected.
Note that the content ratio of carbon element was 3% by mass, and the average particle diameter (volume-based median diameter D50) of both NiSiOC particles and TiSiOC particles was 7 μm.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
＜表Ａの注＞
ＮｉＳｉＯ：ニッケルドープされた酸化ケイ素
ＴｉＳｉＯ：チタンドープされた酸化ケイ素
合金組成：金属元素をドープされたケイ素系材料（ＮｉＳｉＯ又はＴｉＳｉＯ）を得る際に投入したＳｉ合金及びＳｉＯ２粉末の合計１００質量％に占めるＳｉ合金中の各金属元素の割合を示し、単位は質量％であり、合金組成の合計は９５質量％である。
混合割合：金属元素をドープされたケイ素系材料（ＮｉＳｉＯ又はＴｉＳｉＯ）を得る際に投入したＳｉ合金及びＳｉＯ２粉末の合計に占める各成分（Ｓｉ合金又はＳｉＯ２粉末）の割合を示し、単位は質量％である。 <Notes to Table A>
NiSiO: Nickel-doped silicon oxide TiSiO: Titanium-doped silicon oxide alloy Composition: Total of 100% by mass of Si alloy and SiO 2 powder input when obtaining a silicon-based material (NiSiO or TiSiO) doped with a metal element It shows the proportion of each metal element in the Si alloy, the unit is mass %, and the total alloy composition is 95 mass %.
Mixing ratio: Indicates the ratio of each component (Si alloy or SiO 2 powder) to the total amount of Si alloy and SiO 2 powder added when obtaining a silicon-based material (NiSiO or TiSiO) doped with a metal element, and the unit is Mass%.
２．電極用組成物の調製
　電極用組成物Ｅ１の調製において、カーボンコートされた酸化ケイ素を上記カーボンコート及びニッケルドープの両方が施された酸化ケイ素（ＮｉＳｉＯＣ）に変更したこと、及びバインダー成分（水溶性高分子（Ｘ）、水溶性化合物（Ｙ）及び重合体粒子（Ｚ））の組成が後記表１に記載の各バインダー組成物と同様になるように変更したこと以外は、電極用組成物Ｅ１の調製と同様にして、電極用組成物Ｅ１３～Ｅ１８及びｃＥ１７～ｃＥ２３を調製した。後記表３の「対応するバインダー組成物Ｎｏ．」欄に対応するバインダー組成物を示す。
　また、電極用組成物Ｅ１の調製において、カーボンコートされた酸化ケイ素を上記カーボンコート及びチタンドープの両方が施された酸化ケイ素（ＴｉＳｉＯＣ）に変更したこと、及びバインダー成分（水溶性高分子（Ｘ）、水溶性化合物（Ｙ）及び重合体粒子（Ｚ））の組成が後記表１に記載の各バインダー組成物と同様になるように変更したこと以外は、電極用組成物Ｅ１の調製と同様にして、電極用組成物Ｅ１９～Ｅ２４及びｃＥ２４～ｃＥ３０を調製した。後記表３の「対応するバインダー組成物Ｎｏ．」欄に対応するバインダー組成物を示す。 2. Preparation of electrode composition In the preparation of electrode composition E1, the carbon-coated silicon oxide was changed to the carbon-coated and nickel-doped silicon oxide (NiSiOC), and the binder component (water-soluble Electrode composition E1 except that the compositions of polymer (X), water-soluble compound (Y), and polymer particles (Z) were changed to be the same as each binder composition listed in Table 1 below. Electrode compositions E13 to E18 and cE17 to cE23 were prepared in the same manner as in the preparation. The corresponding binder compositions are shown in the "Corresponding Binder Composition No." column in Table 3 below.
In addition, in the preparation of electrode composition E1, the carbon-coated silicon oxide was changed to silicon oxide (TiSiOC) that was both carbon-coated and titanium-doped, and the binder component (water-soluble polymer (X ), water-soluble compound (Y) and polymer particles (Z)) were changed to be the same as each binder composition listed in Table 1 below. Accordingly, electrode compositions E19 to E24 and cE24 to cE30 were prepared. The corresponding binder compositions are shown in the "Corresponding Binder Composition No." column in Table 3 below.
［電極用組成物のひずみ分散測定、貯蔵弾性率の差の算出３］
　電極用組成物Ｅ１３～Ｅ２４及びｃＥ１７～ｃＥ３０についても、ひずみ分散測定を行い、せん断ひずみ０．０１％での貯蔵弾性率とせん断ひずみ１０％での貯蔵弾性率とを読み取り、これらの差を算出した。測定は、スラリーとして各電極用組成物Ｅ１３～Ｅ２４及びｃＥ１７～ｃＥ３０を用いた以外は、上記［電極用組成物のひずみ分散測定、貯蔵弾性率の差の算出１］と同様にして行った。結果を後記表３に示す。 [Strain dispersion measurement of electrode composition, calculation of difference in storage modulus 3]
For the electrode compositions E13 to E24 and cE17 to cE30, strain dispersion measurements were also performed, and the storage modulus at a shear strain of 0.01% and the storage modulus at a shear strain of 10% were read, and the difference between them was calculated. did. The measurement was carried out in the same manner as described above [Strain dispersion measurement of electrode composition, calculation of difference in storage modulus 1] except that each electrode composition E13 to E24 and cE17 to cE30 was used as the slurry. The results are shown in Table 3 below.
［電極の剥離強度の評価］
　上記で調製した各電極用組成物０．７ｍＬを、厚み２０μｍの銅箔上に、アプリケーターにより塗布し、９０℃１時間で乾燥させた。更に、１００℃真空で１０時間乾燥することで、剥離強度測定用の負極シート（負極活物質層＋銅箔）を得た。負極活物質層の厚みは６５μｍであった。得られた電極シートから、横１０ｍｍ、縦５０ｍｍの試験片を３枚切り出した。
　切り出した３枚の試験片の各々の負極活物質層に、粘着テープ（横１０ｍｍ、縦５０ｍｍ、商品名：ナイスタック　ビジネスパック、ニチバン社製）を貼り、９０°の角度で１００ｍｍ／ｍｉｎで引き剥がした際の平均応力を各試験片について測定した。測定には、卓上小型試験機（ＦＧＳ－ＴＶ（商品名）、日本電産シンポ社製）を用いた。得られた各平均応力の合計を３で割って得られた値（単位：Ｎ／ｍ）を後記表２及び表３の「剥離強度」欄に示す。 [Evaluation of peel strength of electrode]
0.7 mL of each electrode composition prepared above was applied onto a 20 μm thick copper foil using an applicator and dried at 90° C. for 1 hour. Furthermore, by drying in vacuum at 100° C. for 10 hours, a negative electrode sheet (negative electrode active material layer + copper foil) for peel strength measurement was obtained. The thickness of the negative electrode active material layer was 65 μm. Three test pieces measuring 10 mm in width and 50 mm in length were cut out from the obtained electrode sheet.
Adhesive tape (width: 10 mm, height: 50 mm, product name: Nystack Business Pack, manufactured by Nichiban Co., Ltd.) was pasted on the negative electrode active material layer of each of the three test pieces that were cut out, and pulled at a rate of 100 mm/min at a 90° angle. The average stress upon peeling was measured for each test piece. For the measurement, a small desktop tester (FGS-TV (trade name), manufactured by Nidec-Shimpo Corporation) was used. The value (unit: N/m) obtained by dividing the sum of the obtained average stresses by 3 is shown in the "peel strength" column of Tables 2 and 3 below.
［非水電解液二次電池（２０３２型コイン電池）の作製］
（非水電解液二次電池１０１）
　非水電解液二次電池１０１を作製した。
　上記で調製した各電極用組成物を厚み２０μｍの銅箔（集電体）上に、アプリケーターにより塗布し、９０℃、１時間で乾燥させた。その後、プレス機を用いて、加圧したのちに１００℃真空で１０時間乾燥することで、負極活物質層の厚さが２５μｍの負極シート（負極活物質層＋銅箔）を得た。
　上記負極シートから直径１３．０ｍｍの円板を切り出し、円盤状の負極シートを得た。
　リチウム箔（厚み５０μｍ、１４．５ｍｍφ）、ポリプロピレン製セパレータ（厚み２５μｍ、１６．０ｍｍφ）の順番に重ねＬｉＰＦ６のエチレンカーボネート／エチルメチルカーボネート（体積比１対２）電解液（濃度１Ｍ）を２００μＬセパレータに浸み込ませた。セパレータの上に更に上記電解液を２００μＬ浸み込ませて、円盤状の負極シートを負極活物質層面がセパレータに接するようにして重ねた。その後、２０３２型コインケースをかしめることで、非水電解液二次電池１０１（Ｌｉ箔－セパレータ－負極活物質層－銅箔からなる積層体を有する電池）を作製した。 [Production of non-aqueous electrolyte secondary battery (2032 type coin battery)]
(Nonaqueous electrolyte secondary battery 101)
A non-aqueous electrolyte secondary battery 101 was produced.
Each electrode composition prepared above was applied onto a 20 μm thick copper foil (current collector) using an applicator and dried at 90° C. for 1 hour. Thereafter, it was pressurized using a press and then dried at 100° C. in vacuum for 10 hours to obtain a negative electrode sheet (negative electrode active material layer + copper foil) with a negative electrode active material layer having a thickness of 25 μm.
A disk with a diameter of 13.0 mm was cut out from the negative electrode sheet to obtain a disk-shaped negative electrode sheet.
Lithium foil (thickness 50 μm, 14.5 mmφ) and polypropylene separator (thickness 25 μm, 16.0 mmφ) are stacked in this order, and 200 μL of LiPF 6 ethylene carbonate/ethyl methyl carbonate (volume ratio 1:2) electrolyte (concentration 1M) is added. It soaked into the separator. 200 μL of the above electrolyte solution was further soaked onto the separator, and a disk-shaped negative electrode sheet was stacked so that the negative electrode active material layer surface was in contact with the separator. Thereafter, the 2032 type coin case was caulked to produce a nonaqueous electrolyte secondary battery 101 (a battery having a laminate consisting of Li foil, separator, negative electrode active material layer, and copper foil).
（非水電解液二次電池１０２～１２４及びｃ１０１～ｃ１３０）
　非水電解液二次電池１０１の作製において、後記表２及び表３に記載する電極用組成物をそれぞれ採用したこと以外は、非水電解液二次電池１０１と同様にして、非水電解液二次電池１０２～１２４及びｃ１０１～ｃ１３０を調製した。 (Non-aqueous electrolyte secondary batteries 102 to 124 and c101 to c130)
In producing the non-aqueous electrolyte secondary battery 101, the non-aqueous electrolyte Secondary batteries 102 to 124 and c101 to c130 were prepared.
［サイクル特性の評価］
　各コイン電池の放電容量維持率を、充放電評価装置：ＴＯＳＣＡＴ－３０００（商品名、東洋システム社製）により測定した。充電は、Ｃレート０．２Ｃ（５時間で満充電になる速度）で電池電圧が０．０２Ｖに達するまで行った。放電は、Ｃレート０．２Ｃで電池電圧が１．５Ｖに達するまで行った。この充電１回と放電１回とを充放電１サイクルとして３サイクル充放電を繰り返して、各コイン電池を初期化した。
　初期化後、充電を０．５Ｃで０．０２Ｖに達するまで行った。放電を０．５Ｃで１．５Ｖに達するまで行った。この充電１回と放電１回を充放電１サイクルとして、８０サイクル充放電を繰り返すことでサイクル特性の評価を行った。
　初期化後１サイクル目の放電容量（初期放電容量）を１００％としたとき、８０サイクル充放電後の放電容量維持率（１００×「８０サイクル充放電後の放電容量」／「初期放電容量」）を算出した。結果を後記表２及び表３の「容量維持率８０ｃｙｃ」欄に記載する。
　なお、充放電はいずれも２５℃で行った。 [Evaluation of cycle characteristics]
The discharge capacity retention rate of each coin battery was measured using a charge/discharge evaluation device: TOSCAT-3000 (trade name, manufactured by Toyo System Co., Ltd.). Charging was carried out at a C rate of 0.2C (a rate at which full charge was achieved in 5 hours) until the battery voltage reached 0.02V. Discharge was performed at a C rate of 0.2C until the battery voltage reached 1.5V. Each coin battery was initialized by repeating three cycles of charging and discharging, with one charging and one discharging as one charging/discharging cycle.
After initialization, charging was performed at 0.5C until the voltage reached 0.02V. Discharge was performed at 0.5C until reaching 1.5V. The cycle characteristics were evaluated by repeating 80 cycles of charging and discharging, with one charging and one discharging being defined as one charging/discharging cycle.
When the discharge capacity at the first cycle after initialization (initial discharge capacity) is taken as 100%, the discharge capacity retention rate after 80 cycles of charging and discharging (100 x "Discharge capacity after 80 cycles of charging and discharging" / "Initial discharge capacity" ) was calculated. The results are listed in the "Capacity Retention Rate 80 cyc" column in Tables 2 and 3 below.
Note that both charging and discharging were performed at 25°C.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
＜表１の注＞
「－」：該当する成分を含有しないことを示す。
ＰＡＡｍ：ポリアクリルアミド
ＰＡＡｍ－ＨＥＡＡ－ＴＢＡＡｍ：アクリルアミド／Ｎ－（２－ヒドロキシエチル）アクリルアミド／ｔｅｒｔ－ブチルアクリルアミド＝８５／１０／５（質量比）のコポリマー
ＰＡＡｍ－ＡＮ：アクリルアミド／アクリロニトリル＝８０／２０（質量比）のコポリマー
ＣＬＰＡ－Ｃ０７：商品名、アクリル酸と疎水性モノマーからなる架橋型共重合バインダー、富士フイルム和光純薬社製
ＣＬＰＡ－Ｗ１１：商品名、架橋型ポリアクリル酸バインダー、富士フイルム和光純薬社製
ＣＭＣ：カルボキシメチルセルロース（エーテル化度０．６６、商品名：セロゲンＷＳ－Ｃ、第一工業製薬社製）
セレンピア：商品名、セルロースナノファイバー、日本製紙社製
重合体粒子１：特開２０１２－２１２５３７号公報の段落番号００３８に記載の共重合体ラテックス１の作製例に従って合成した。
　重合体粒子２：特開２０１１－１７１１８１号公報の段落番号００４４に記載の共重合体ラテックス（Ｂ－２）の合成例に従って合成した。
　＊重合体粒子１及び２は、いずれも、２０℃において水に対して１０ｇ／Ｌ－Ｈ２Ｏ未満の溶解度を示した。
水ガラス：珪酸ナトリウム水溶液、富士フイルム和光純薬社製
ＳｉＯＣ：カーボンコートされた酸化ケイ素（大阪チタニウムテクノロジーズ社製、グレード：ＳｉＯ　ＮＣ　５μｍ、平均粒径：５μｍ、比表面積：２．６ｍ２／ｇ、炭素元素の含有量の割合１．３質量％）
黒鉛：ＭＡＧ－Ｄ（商品名、昭和電工マテリアルズ社製、平均粒径：２１μｍ、比表面積：４ｍ２／ｇ）
ＡＢ：アセチレンブラック（商品名：デンカブラック、デンカ社製、粉状品、平均粒径：３５ｎｍ、比表面積：６８ｍ２／ｇ）
含有量：電極用組成物に含まれる各成分（固形分）の合計に占める各成分（固形分）の割合を示し、単位は質量％である。
ＧＡ’：せん断ひずみ０．０１％における貯蔵弾性率
ＧＢ’：せん断ひずみ１０％における貯蔵弾性率 <Notes on Table 1>
"-": Indicates that the corresponding component is not contained.
PAAm: Polyacrylamide PAAm-HEAA-TBAAm: Copolymer of acrylamide/N-(2-hydroxyethyl)acrylamide/tert-butylacrylamide = 85/10/5 (mass ratio) PAAm-AN: Acrylamide/acrylonitrile = 80/20 ( Mass ratio) copolymer CLPA-C07: trade name, crosslinked copolymer binder consisting of acrylic acid and hydrophobic monomer, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. CLPA-W11: trade name, crosslinked polyacrylic acid binder, Fujifilm Wa CMC manufactured by Hikari Pure Chemical Industries: Carboxymethylcellulose (degree of etherification 0.66, trade name: Celogen WS-C, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
Selenpia: trade name, cellulose nanofiber, manufactured by Nippon Paper Industries Co., Ltd. Polymer particles 1: Synthesized according to the preparation example of copolymer latex 1 described in paragraph number 0038 of JP-A-2012-212537.
Polymer particles 2: Synthesized according to the synthesis example of copolymer latex (B-2) described in paragraph number 0044 of JP-A-2011-171181.
* Polymer particles 1 and 2 both exhibited solubility in water of less than 10 g/L-H 2 O at 20°C.
Water glass: Sodium silicate aqueous solution, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. SiOC: Carbon-coated silicon oxide (manufactured by Osaka Titanium Technologies, grade: SiO NC 5 μm, average particle size: 5 μm, specific surface area: 2.6 m 2 /g , carbon element content ratio 1.3% by mass)
Graphite: MAG-D (trade name, manufactured by Showa Denko Materials Co., Ltd., average particle size: 21 μm, specific surface area: 4 m 2 /g)
AB: Acetylene black (trade name: Denka Black, manufactured by Denka Corporation, powdered product, average particle size: 35 nm, specific surface area: 68 m 2 /g)
Content: Indicates the proportion of each component (solid content) in the total of each component (solid content) contained in the electrode composition, and the unit is mass %.
G A ': Storage modulus at 0.01% shear strain G B ': Storage modulus at 10% shear strain
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
＜表２の注＞
　二次電池１０１～１１２及びｃ１０１～ｃ１１６：非水電解液二次電池１０１～１１２及びｃ１０１～ｃ１１６
　対応するバインダー組成物Ｎｏ．：電極用組成物に配合したバインダー成分（水溶性高分子（Ｘ）、水溶性化合物（Ｙ）及び重合体粒子（Ｚ））の組合せに対応するバインダー組成物Ｎｏ．
ＳｉＯＣ：カーボンコートされた酸化ケイ素（大阪チタニウムテクノロジーズ社製、グレード：ＳｉＯ　ＮＣ　５μｍ、平均粒径：５μｍ、比表面積：２．６ｍ２／ｇ、炭素元素の含有量の割合１．３質量％）
ＬｉＳｉＯＣ：上記で調製したカーボンコート及びリチウムドープの両方が施された酸化ケイ素（平均粒径：６．７μｍ、炭素元素の含有量の割合３質量％）
黒鉛：ＭＡＧ－Ｄ（商品名、昭和電工マテリアルズ社製、平均粒径：２１μｍ、比表面積：４ｍ２／ｇ）
ＡＢ：アセチレンブラック（商品名：デンカブラック、デンカ社製、粉状品、平均粒径：３５ｎｍ、比表面積：６８ｍ２／ｇ）
含有量：電極用組成物に含まれる各成分（固形分）の合計に占める各成分（固形分）の割合を示し、単位は質量％である。
ＧＣ’：せん断ひずみ０．０１％における貯蔵弾性率
ＧＤ’：せん断ひずみ１０％における貯蔵弾性率 <Notes on Table 2>
Secondary batteries 101-112 and c101-c116: Non-aqueous electrolyte secondary batteries 101-112 and c101-c116
Corresponding binder composition no. : Binder composition No. corresponding to the combination of binder components (water-soluble polymer (X), water-soluble compound (Y), and polymer particles (Z)) blended into the electrode composition.
SiOC: carbon-coated silicon oxide (manufactured by Osaka Titanium Technologies, grade: SiO NC 5 μm, average particle size: 5 μm, specific surface area: 2.6 m 2 /g, carbon element content ratio 1.3% by mass)
LiSiOC: Silicon oxide prepared above with both the carbon coat and lithium doping (average particle size: 6.7 μm, carbon element content ratio 3% by mass)
Graphite: MAG-D (trade name, manufactured by Showa Denko Materials Co., Ltd., average particle size: 21 μm, specific surface area: 4 m 2 /g)
AB: Acetylene black (trade name: Denka Black, manufactured by Denka Corporation, powdered product, average particle size: 35 nm, specific surface area: 68 m 2 /g)
Content: Indicates the proportion of each component (solid content) in the total of each component (solid content) contained in the electrode composition, and the unit is mass %.
G C ': Storage modulus at 0.01% shear strain G D ': Storage modulus at 10% shear strain
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
＜表３の注＞
　二次電池１１３～１２４及びｃ１１７～ｃ１３０：非水電解液二次電池１１３～１２４及びｃ１１７～ｃ１３０
　対応するバインダー組成物Ｎｏ．：電極用組成物に配合したバインダー成分（水溶性高分子（Ｘ）、水溶性化合物（Ｙ）及び重合体粒子（Ｚ））の組合せに対応するバインダー組成物Ｎｏ．
ＮｉＳｉＯＣ：上記で調製したカーボンコート及びニッケルドープの両方が施された酸化ケイ素（平均粒径：７μｍ、炭素元素の含有量の割合３質量％）
ＴｉＳｉＯＣ：上記で調製したカーボンコート及びチタンドープの両方が施された酸化ケイ素（平均粒径：７μｍ、炭素元素の含有量の割合３質量％）
黒鉛：ＭＡＧ－Ｄ（商品名、昭和電工マテリアルズ社製、平均粒径：２１μｍ、比表面積：４ｍ２／ｇ）
ＡＢ：アセチレンブラック（商品名：デンカブラック、デンカ社製、粉状品、平均粒径：３５ｎｍ、比表面積：６８ｍ２／ｇ）
含有量：電極用組成物に含まれる各成分（固形分）の合計に占める各成分（固形分）の割合を示し、単位は質量％である。
ＧＣ’：せん断ひずみ０．０１％における貯蔵弾性率
ＧＤ’：せん断ひずみ１０％における貯蔵弾性率 <Notes on Table 3>
Secondary batteries 113-124 and c117-c130: Non-aqueous electrolyte secondary batteries 113-124 and c117-c130
Corresponding binder composition no. : Binder composition No. corresponding to the combination of binder components (water-soluble polymer (X), water-soluble compound (Y), and polymer particles (Z)) blended into the electrode composition.
NiSiOC: Silicon oxide prepared above with both carbon coat and nickel doping (average particle size: 7 μm, carbon element content ratio 3% by mass)
TiSiOC: Silicon oxide prepared above with both the carbon coat and titanium doping (average particle size: 7 μm, carbon element content ratio 3% by mass)
Graphite: MAG-D (trade name, manufactured by Showa Denko Materials Co., Ltd., average particle size: 21 μm, specific surface area: 4 m 2 /g)
AB: Acetylene black (trade name: Denka Black, manufactured by Denka Corporation, powdered product, average particle size: 35 nm, specific surface area: 68 m 2 /g)
Content: Indicates the proportion of each component (solid content) in the total of each component (solid content) contained in the electrode composition, and the unit is mass %.
G C ': Storage modulus at 0.01% shear strain G D ': Storage modulus at 10% shear strain
　表１、表２及び表３から以下のことが分かる。
　バインダー組成物ｃ１～ｃ９は、一般式（Ｂ－２）で表される構成成分を含有する水溶性高分子（Ｘ）、水溶性化合物（Ｙ）、重合体粒子、及び水を含有すること、引張弾性率が１５００～９８００ＭＰａであること、せん断ひずみ０．０１％における貯蔵弾性率ＧＡ’とせん断ひずみ１０％における貯蔵弾性率ＧＢ’との差（ＧＡ’－ＧＢ’）が１００～１０００Ｐａとなること（＜貯蔵弾性率特性１＞を満たすこと）の少なくとも１つを満たさないバインダー組成物である。バインダー組成物ｃ１～ｃ９は、高容量活物質としてカーボンコートされた酸化ケイ素を採用した電極用組成物ｃＥ１～ｃＥ９に用いた場合であってもカーボンコート及び金属元素のドープの両方が施された酸化ケイ素を採用した電極用組成物ｃＥ１０～ｃＥ３０に用いた場合であっても、剥離強度が１５．４Ｎ／ｍ以下、サイクル特性も９０％を下回っており、いずれも、密着性を高めることができず、及び／又は、二次電池のサイクル特性を向上させることができなかった。
　バインダー組成物１～６は、一般式（Ｂ－２）で表される構成成分を含有する水溶性高分子（Ｘ）、水溶性化合物（Ｙ）、重合体粒子、及び水を含有し、引張弾性率が１５００～９８００ＭＰａであり、かつ、バインダー組成物のせん断ひずみ０．０１％における貯蔵弾性率ＧＡ’とせん断ひずみ１０％における貯蔵弾性率ＧＢ’との差（ＧＡ’－ＧＢ’）が１００～１０００Ｐａとなる（＜貯蔵弾性率特性１＞を満たす）バインダー組成物である。バインダー組成物１～６は、高容量活物質としてカーボンコートされた酸化ケイ素を採用した電極用組成物Ｅ１～Ｅ６に用いた場合であってもカーボンコート及び金属元素のドープの両方が施された酸化ケイ素を採用した電極用組成物Ｅ７～Ｅ２４に用いた場合であっても、密着性を高めることができ、かつ、二次電池のサイクル特性を向上させることができた。体積変化しやすいケイ素系活物質を用いているにもかかわらず、サイクル特性に優れることから、本発明の電極用組成物により、導電ネットワーク構造の破壊が抑制されていると考えられる。
　本発明の電極用組成物は、得られる負極シートの密着性を十分に高め、得られる二次電池のサイクル特性を高めることができることがわかる。本発明のバインダー組成物は、本発明の電極用組成物を得ることができることがわかる。また、本発明の電極用組成物を用いた電極シート及び二次電池は、密着性が高く、また、サイクル特性に優れることがわかる。 The following can be seen from Tables 1, 2, and 3.
Binder compositions c1 to c9 contain a water-soluble polymer (X) containing a component represented by general formula (B-2), a water-soluble compound (Y), polymer particles, and water; The tensile modulus is 1500 to 9800 MPa, and the difference between the storage modulus G A ' at a shear strain of 0.01% and the storage modulus G B ' at a shear strain of 10% (G A '-G B ') is 100 This is a binder composition that does not satisfy at least one of the following conditions: Binder compositions c1 to c9 were coated with both carbon and doped with a metal element even when used in electrode compositions cE1 to cE9 that employed carbon-coated silicon oxide as a high-capacity active material. Even when using electrode compositions cE10 to cE30 that employ silicon oxide, the peel strength was less than 15.4 N/m and the cycle characteristics were less than 90%, and in both cases, it was difficult to improve adhesion. and/or it was not possible to improve the cycle characteristics of the secondary battery.
Binder compositions 1 to 6 contain a water-soluble polymer (X) containing a component represented by general formula (B-2), a water-soluble compound (Y), polymer particles, and water, and The difference between the storage elastic modulus G A ' at a shear strain of 0.01% and the storage elastic modulus G B ' at a shear strain of 10% of the binder composition when the elastic modulus is 1500 to 9800 MPa (G A '-G B ') is 100 to 1000 Pa (satisfying <storage modulus property 1>). Binder compositions 1 to 6 were coated with both carbon and doped with a metal element even when used in electrode compositions E1 to E6, which employed carbon-coated silicon oxide as a high-capacity active material. Even when electrode compositions E7 to E24 employing silicon oxide were used, it was possible to increase the adhesion and improve the cycle characteristics of the secondary battery. Despite using a silicon-based active material that is prone to change in volume, it is considered that the electrode composition of the present invention suppresses destruction of the conductive network structure because it has excellent cycle characteristics.
It can be seen that the electrode composition of the present invention can sufficiently improve the adhesion of the obtained negative electrode sheet and improve the cycle characteristics of the obtained secondary battery. It can be seen that the binder composition of the present invention can be used to obtain the electrode composition of the present invention. Furthermore, it can be seen that the electrode sheet and secondary battery using the electrode composition of the present invention have high adhesion and excellent cycle characteristics.
　本発明をその実施態様とともに説明したが、我々は特に指定しない限り我々の発明を説明のどの細部においても限定しようとするものではなく、添付の請求の範囲に示した発明の精神と範囲に反することなく幅広く解釈されるべきであると考える。 Although the invention has been described in conjunction with embodiments thereof, we do not intend to limit our invention in any detail in the description unless otherwise specified and contrary to the spirit and scope of the invention as set forth in the appended claims. I believe that it should be interpreted broadly without any restrictions.
　本願は、２０２２年７月２９日に日本国で特許出願された特願２０２２－１２２２３３及び２０２２年１０月１４日に日本国で特許出願された特願２０２２－１６５８８３に基づく優先権を主張するものであり、これらはここに参照してその内容を本明細書の記載の一部として取り込む。 This application claims priority based on Japanese Patent Application No. 2022-122233, which was filed in Japan on July 29, 2022, and Japanese Patent Application No. 2022-165883, which was filed in Japan on October 14, 2022. and these are hereby incorporated by reference and their contents are incorporated as part of the description of this specification.
１０　非水電解液二次電池
　１　負極集電体
　２　負極活物質層
　３　セパレータ
　４　正極活物質層
　５　正極集電体
　６　作動部位（電球）
  10 Nonaqueous electrolyte secondary battery 1 Negative electrode current collector 2 Negative electrode active material layer 3 Separator 4 Positive electrode active material layer 5 Positive electrode current collector 6 Operating part (light bulb)

Claims (16)

  1. 　水溶性高分子（Ｘ）、水溶性化合物（Ｙ）、重合体粒子及び水を含む二次電池用バインダー組成物であって、
    　前記水溶性高分子（Ｘ）は、下記一般式（Ｂ－２）で表される構成成分を含む重合体であり、
    　前記バインダー組成物の引張弾性率が１５００～９８００ＭＰａであり、且つ、
    　下記＜貯蔵弾性率特性１＞を満たす、二次電池用バインダー組成物。
    ＜貯蔵弾性率特性１＞
    　平均粒径が１～１０μｍかつ比表面積１～１０ｍ２／ｇの粉末状であるカーボンコートされた酸化ケイ素と、平均粒径が１５～２５μｍかつ比表面積１～１０ｍ２／ｇの粉末状である黒鉛と、平均粒径が３０～４０ｎｍかつ比表面積６５～７５ｍ２／ｇの粉末状であるアセチレンブラックと、前記二次電池用バインダー組成物とを下記量比となるよう調製したスラリーにおいて、該スラリーのせん断ひずみ０．０１％における貯蔵弾性率ＧＡ’とせん断ひずみ１０％における貯蔵弾性率ＧＢ’との差が１００～１０００Ｐａとなる特性。
    －量比－
    　スラリー中の全固形分１００質量部に対して、前記カーボンコートされた酸化ケイ素の含有量を１７．８質量部、前記黒鉛の含有量を７１．２質量部、前記アセチレンブラックの含有量を６質量部、前記二次電池用バインダー組成物中の固形分の含有量を５質量部とし、かつスラリー中の全固形分量を５２質量％とする。
    Figure JPOXMLDOC01-appb-I000001
    　一般式（Ｂ－２）中、Ｒ２１～Ｒ２３は水素原子、シアノ基又は炭素数１～６のアルキル基を示し、Ｒ２４は水素原子、アシル基、ヒドロキシ基、フェニル基又はカルボキシ基を示し、Ｌ２１は単結合、炭素数１～１６のアルキレン基、炭素数６～１２のアリーレン基、酸素原子、硫黄原子、カルボニル基若しくはイミノ基、又はこれらを組み合わせた連結基を示す。＊は前記水溶性高分子（Ｘ）の主鎖中に組み込まれるための結合部位を示す。     A binder composition for a secondary battery comprising a water-soluble polymer (X), a water-soluble compound (Y), polymer particles, and water,
    The water-soluble polymer (X) is a polymer containing a component represented by the following general formula (B-2),
    The binder composition has a tensile modulus of 1500 to 9800 MPa, and
    A binder composition for secondary batteries that satisfies the following <Storage Modulus Characteristics 1>.
    <Storage modulus characteristics 1>
    Carbon-coated silicon oxide in powder form with an average particle size of 1 to 10 μm and a specific surface area of 1 to 10 m 2 /g; and powdered silicon oxide with an average particle size of 15 to 25 μm and a specific surface area of 1 to 10 m 2 /g. In a slurry prepared by mixing graphite, acetylene black in powder form with an average particle size of 30 to 40 nm and a specific surface area of 65 to 75 m 2 /g, and the binder composition for secondary batteries in the following quantitative ratio, Characteristics such that the difference between the storage elastic modulus G A ' at a shear strain of 0.01% and the storage elastic modulus G B ' at a shear strain of 10% of the slurry is 100 to 1000 Pa.
    -Quantity ratio-
    With respect to 100 parts by mass of the total solid content in the slurry, the content of the carbon-coated silicon oxide is 17.8 parts by mass, the content of the graphite is 71.2 parts by mass, and the content of the acetylene black is 6 parts by mass. The solid content in the binder composition for secondary batteries is 5 parts by mass, and the total solid content in the slurry is 52% by mass.
    Figure JPOXMLDOC01-appb-I000001
    In the general formula (B-2), R 21 to R 23 represent a hydrogen atom, a cyano group, or an alkyl group having 1 to 6 carbon atoms, and R 24 represents a hydrogen atom, an acyl group, a hydroxy group, a phenyl group, or a carboxy group. and L 21 represents a single bond, an alkylene group having 1 to 16 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom, a sulfur atom, a carbonyl group or an imino group, or a linking group combining these. * indicates a binding site for incorporation into the main chain of the water-soluble polymer (X).
  2. 　前記水溶性高分子（Ｘ）中、前記一般式（Ｂ－２）で表される構成成分の含有量が８０質量％以上である、請求項１に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 1, wherein the content of the component represented by the general formula (B-2) in the water-soluble polymer (X) is 80% by mass or more.
  3. 　前記一般式（Ｂ－２）で表される構成成分が（メタ）アクリルアミド成分を含む、請求項１に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 1, wherein the component represented by the general formula (B-2) includes a (meth)acrylamide component.
  4. 　前記水溶性高分子（Ｘ）が、アクリロニトリル成分、Ｎ－ビニル－２－ピロリドン成分及びスチレン成分の少なくとも１種を、更に含む重合体である、請求項１に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 1, wherein the water-soluble polymer (X) is a polymer further containing at least one of an acrylonitrile component, an N-vinyl-2-pyrrolidone component, and a styrene component. .
  5. 　前記水溶性化合物（Ｙ）が多糖類を含む、請求項１に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 1, wherein the water-soluble compound (Y) contains a polysaccharide.
  6. 　前記水溶性化合物（Ｙ）が、カルボキシメチルセルロース、セルロースナノファイバー、ヒドロキシエチルセルロース、ヒドロキシプロピルセルロース及びキサンタンガムの少なくとも１種を含む、請求項１に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 1, wherein the water-soluble compound (Y) contains at least one of carboxymethyl cellulose, cellulose nanofiber, hydroxyethyl cellulose, hydroxypropyl cellulose, and xanthan gum.
  7. 　前記水溶性高分子（Ｘ）の分子量分布が５．０以下である、請求項１に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 1, wherein the water-soluble polymer (X) has a molecular weight distribution of 5.0 or less.
  8. 　前記水溶性高分子（Ｘ）の引張弾性率が４０００ＭＰａ以上である、請求項１に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 1, wherein the water-soluble polymer (X) has a tensile modulus of 4000 MPa or more.
  9. 　前記重合体粒子を構成する重合体が、共役ジエン成分、エチレン性不飽和カルボン酸成分、シアノ基含有エチレン性モノマー成分及び芳香族ビニルモノマー成分の少なくとも１種を含む重合体である、請求項１に記載の二次電池用バインダー組成物。 Claim 1, wherein the polymer constituting the polymer particles is a polymer containing at least one of a conjugated diene component, an ethylenically unsaturated carboxylic acid component, a cyano group-containing ethylenic monomer component, and an aromatic vinyl monomer component. A binder composition for secondary batteries as described in .
  10. 　前記重合体粒子のガラス転移温度が－５０～１５０℃である、請求項１に記載の二次電池用バインダー組成物。 The binder composition for a secondary battery according to claim 1, wherein the polymer particles have a glass transition temperature of -50 to 150°C.
  11. 　請求項１に記載の二次電池用バインダー組成物と、周期律表第１族又は第２族に属する金属のイオンの挿入放出が可能な活物質と、導電助剤とを含有する、電極用組成物。 An electrode comprising the binder composition for a secondary battery according to claim 1, an active material capable of intercalating and releasing metal ions belonging to Group 1 or 2 of the periodic table, and a conductive additive. Composition.
  12. 　前記活物質がケイ素系活物質を含む、請求項１１に記載の電極用組成物。 The electrode composition according to claim 11, wherein the active material includes a silicon-based active material.
  13. 　請求項１１又は１２に記載の電極用組成物を用いて形成された層を有する電極シート。 An electrode sheet having a layer formed using the electrode composition according to claim 11 or 12.
  14. 　正極活物質層及び負極活物質層の少なくとも１つの層が、請求項１１又は１２に記載の電極用組成物を用いて形成された層である、二次電池。 A secondary battery, wherein at least one of the positive electrode active material layer and the negative electrode active material layer is a layer formed using the electrode composition according to claim 11 or 12.
  15. 　請求項１１又は１２に記載の電極用組成物を用いて電極活物質層を形成することを含む、電極シートの製造方法。 A method for manufacturing an electrode sheet, comprising forming an electrode active material layer using the electrode composition according to claim 11 or 12.
  16. 　請求項１５に記載の製造方法により得られた電極シートを二次電池の電極として組み込むことを含む、二次電池の製造方法。 A method for manufacturing a secondary battery, comprising incorporating an electrode sheet obtained by the manufacturing method according to claim 15 as an electrode of the secondary battery.
PCT/JP2023/027792 2022-07-29 2023-07-28 Binder composition for secondary battery, composition for electrode, electrode sheet, secondary battery, manufacturing method for said electrode sheet, and manufacturing method for said secondary battery WO2024024949A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
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WO2017056467A1 (en) * 2015-09-30 2017-04-06 日本ゼオン株式会社 Binder composition for non-aqueous secondary cell electrode, slurry composition for non-aqueous secondary cell electrode, non-aqueous secondary cell electrode, and non-aqueous secondary cell
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