WO2023243590A1 - Composition de liant pour dispositif d'accumulation, bouillie pour batterie secondaire entièrement solide, batterie secondaire entièrement solide ainsi que procédé de fabrication associé, feuille d'électrolyte solide pour batterie secondaire entièrement solide ainsi que procédé de fabrication associé, bouillie pour électrode de batterie secondaire au lithium-ion, électrode pour batterie secondaire au lithium-ion, et batterie secondaire au lithium-ion - Google Patents

Composition de liant pour dispositif d'accumulation, bouillie pour batterie secondaire entièrement solide, batterie secondaire entièrement solide ainsi que procédé de fabrication associé, feuille d'électrolyte solide pour batterie secondaire entièrement solide ainsi que procédé de fabrication associé, bouillie pour électrode de batterie secondaire au lithium-ion, électrode pour batterie secondaire au lithium-ion, et batterie secondaire au lithium-ion Download PDF

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Publication number
WO2023243590A1
WO2023243590A1 PCT/JP2023/021706 JP2023021706W WO2023243590A1 WO 2023243590 A1 WO2023243590 A1 WO 2023243590A1 JP 2023021706 W JP2023021706 W JP 2023021706W WO 2023243590 A1 WO2023243590 A1 WO 2023243590A1
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solid
secondary battery
mass
polymer
slurry
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PCT/JP2023/021706
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English (en)
Japanese (ja)
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卓哉 中山
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株式会社Ｅｎｅｏｓマテリアル
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Publication of WO2023243590A1 publication Critical patent/WO2023243590A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
    • H01M10/0562—Solid materials
    • 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
    • H01M10/058—Construction or 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
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers

Definitions

  • the present invention relates to a binder composition for an electricity storage device, a slurry for an all-solid secondary battery containing the binder composition, an all-solid secondary battery, a solid electrolyte sheet for an all-solid secondary battery, and a solid electrolyte for an all-solid secondary battery.
  • the present invention relates to a method for manufacturing a sheet, a method for manufacturing an all-solid-state secondary battery, and a slurry for a lithium ion secondary battery electrode, an electrode for a lithium ion secondary battery, and a lithium ion secondary battery containing the binder composition.
  • Lithium ion batteries, lithium ion capacitors, and the like are expected to be used as such power storage devices.
  • Electrodes used in such power storage devices are manufactured by applying a composition (slurry for power storage device electrodes) containing an active material and a polymer that functions as a binder onto the surface of a current collector and drying the composition.
  • a composition slurry for power storage device electrodes
  • a polymer that functions as a binder onto the surface of a current collector and drying the composition.
  • Ru Properties required of a polymer used as a binder include the ability to bond between active materials and the ability to adhere to an active material and a current collector. Another example is powder drop resistance, which prevents fine particles of the active material from falling off from the active material layer when the coated and dried composition coating film (hereinafter also referred to as "active material layer”) is cut.
  • active material layer Such a binder material exhibits good adhesion and reduces the internal resistance of the battery caused by the binder material, thereby imparting good charge/discharge characteristics to the electricity storage device.
  • All-solid-state secondary batteries use a solid electrolyte that exhibits high ionic conductivity, so there is no risk of leakage or fire, and they are safe and reliable. All-solid-state secondary batteries are also suitable for increasing energy density by stacking electrodes. Specifically, it is possible to create a battery with a structure in which an active material layer and a solid electrolyte layer are arranged and connected in series, and the metal package that seals the battery cells and the copper wires and bus bars that connect the battery cells can be omitted. As a result, the energy density of the battery can be significantly increased. Another advantage is that it is compatible with positive electrode materials that can be used at high potentials. All-solid-state secondary batteries are thus expected to be the ultimate battery that combines safety, high energy density, and long life.
  • the solubility of the polymer (A) in toluene at 25° C. and 1 atmosphere can be 1 g or more per 100 g of toluene.
  • the binder composition for an electricity storage device When the polymer (A) is subjected to differential scanning calorimetry (DSC) in accordance with JIS K7121:2012, an endothermic peak can be further observed in the temperature range of 80°C to 150°C.
  • DSC differential scanning calorimetry
  • the solid electrolyte may include a sulfide-based solid electrolyte or an oxide-based solid electrolyte.
  • the method includes a step of applying the slurry for an all-solid-state secondary battery according to any of the above embodiments onto a base material and drying the slurry.
  • An all-solid-state secondary battery is manufactured using the method for manufacturing a solid electrolyte sheet for an all-solid-state secondary battery according to the above embodiment.
  • One embodiment of the slurry for lithium ion secondary battery electrodes according to the present invention is It contains the binder composition for a power storage device according to any of the above embodiments and an active material.
  • the active material can be a positive electrode active material.
  • the binder composition for a power storage device contains a polymer (A).
  • the polymer (A) may be in the form of a latex dispersed in a liquid medium (C), which will be described later, or may be in a state dissolved in the liquid medium (C). ) is preferable.
  • the stability of the composition prepared by mixing it with the active material hereinafter also referred to as "slurry" is good, and , is preferable because the slurry can be easily applied to the current collector.
  • the adhesion strength between the active materials increases and ionic conductivity improves. This allows the internal resistance to be reduced, making it easy to obtain a power storage device with excellent cycle life characteristics.
  • the polymer (A) contains repeating units derived from a conjugated diene compound (a1) when the total of repeating units contained in the polymer (A) is 100% by mass. ) (hereinafter also simply referred to as “repeat unit (a1)”) from 50 to 99% by mass, and a repeating unit (a2) derived from an aromatic vinyl compound (hereinafter also simply referred to as “repeat unit (a2)”). ) in an amount of 1 to 50% by mass.
  • the polymer (A) may contain, in addition to the repeating unit (a1) and the repeating unit (a2), a repeating unit derived from another monomer copolymerizable with these units.
  • Conjugated diene compounds include, but are not limited to, 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, etc. One or more types selected from these can be used. Among these, 1,3-butadiene is particularly preferred.
  • Repeating unit (a2) derived from aromatic vinyl compound The content of the repeating unit (a2) derived from the aromatic vinyl compound is 1 to 50% by mass, when the total number of repeating units contained in the polymer (A) is 100% by mass.
  • the lower limit of the content of the repeating unit (a2) is preferably 2% by mass, more preferably 4% by mass.
  • the upper limit of the content of the repeating unit (a2) is preferably 48% by mass, more preferably 45% by mass.
  • the permeability of the electrolytic solution can be improved, good repeated charge/discharge characteristics may be exhibited. Furthermore, it may exhibit good binding strength to graphite or the like used as an active material, and an electricity storage device electrode with excellent adhesion can be obtained.
  • repeating unit (a4) repeating unit (a5) derived from an ⁇ , ⁇ -unsaturated nitrile compound (hereinafter also simply referred to as “repeat unit (a5)”), ( The repeating unit (a6) derived from meth)acrylamide (hereinafter also simply referred to as “repeat unit (a6)”), the repeating unit (a7) derived from a compound having a sulfonic acid group (hereinafter simply referred to as “repeat unit (a7)”) ), repeating units derived from cationic monomers, etc.
  • the polymer (A) contains a repeating unit (a3) derived from an unsaturated carboxylic acid.
  • the content of the repeating unit (a3) derived from unsaturated carboxylic acid may be 0.1 to 10% by mass when the total number of repeating units contained in the polymer (A) is 100% by mass. preferable.
  • the lower limit of the content of the repeating unit (a3) is preferably 0.2% by mass, more preferably 0.3% by mass.
  • the upper limit of the content of the repeating unit (a3) is preferably 8% by mass, more preferably 6% by mass.
  • unsaturated carboxylic acids include, but are not limited to, monocarboxylic acids and dicarboxylic acids (including anhydrides) such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid.
  • monocarboxylic acids and dicarboxylic acids including anhydrides
  • acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid One or more types selected from these can be used. Among these, it is preferable to use one or more selected from acrylic acid, methacrylic acid, and itaconic acid.
  • the affinity between the polymer (A) and the electrolyte becomes good, and the binder becomes an electrical resistance component in the electricity storage device. It may be possible to suppress the increase in internal resistance.
  • (meth)acrylic esters can be preferably used.
  • Specific examples of (meth)acrylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, and n-(meth)acrylate.
  • methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, and di(meth)acrylate Preferably, it is one or more selected from ethylene glycol, and methyl (meth)acrylate is particularly preferable.
  • the polymer (A) may contain a repeating unit (a5) derived from an ⁇ , ⁇ -unsaturated nitrile compound.
  • the content of the repeating unit (a5) is preferably 0 to 10% by mass, when the total number of repeating units contained in the polymer (A) is 100% by mass.
  • the lower limit of the content of the repeating unit (a5) is preferably 0.5% by mass, more preferably 1% by mass.
  • the upper limit of the content of the repeating unit (a5) is preferably 9% by mass, more preferably 8% by mass.
  • the polymer (A) may contain a repeating unit (a6) derived from (meth)acrylamide.
  • (meth)acrylamide include, but are not limited to, acrylamide, methacrylamide, N-isopropylacrylamide, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N,N-diethylacrylamide, and N,N-diethylmethacrylamide.
  • amide, N,N-dimethylaminopropylacrylamide, N,N-dimethylaminopropylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, diacetone acrylamide, maleic acid amide, acrylamide tert-butylsulfonic acid, etc. can be used, and one or more selected from these can be used.
  • the content ratio of the repeating unit (a6) derived from (meth)acrylamide is preferably 0 to 5% by mass, when the total number of repeating units contained in the polymer (A) is 100% by mass, More preferably, it is 1 to 4% by mass.
  • the polymer (A) contains the repeating unit (a6) within the above range the dispersibility of the active material and filler in the slurry may be improved. Further, the flexibility of the obtained active material layer may be moderate, and the adhesion between the current collector and the active material layer may be improved.
  • the polymer (A) may contain repeating units derived from a cationic monomer.
  • the cationic monomer is not particularly limited, but is at least one monomer selected from the group consisting of secondary amines (salts), tertiary amines (salts), and quaternary ammonium salts. It is preferable.
  • cationic monomers include 2-(dimethylamino)ethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate methyl chloride quaternary salt, 2-(diethylamino)ethyl (meth)acrylate, ( 3-(dimethylamino)propyl meth)acrylate, 3-(diethylamino)propyl (meth)acrylate, 4-(dimethylamino)phenyl (meth)acrylate, 2-[(3,5-meth)acrylate dimethylpyrazolyl)carbonylamino]ethyl, 2-(0-[1'-methylpropylideneamino]carboxyamino)ethyl (meth)acrylate, 2-(1-aziridinyl)ethyl (meth)acrylate, methacroylcholine chloride , tris(2-acryloyloxyethyl) isocyanurate, 2-vinylpyridine
  • the weight average molecular weight (Mw) of the polymer (A) in terms of polystyrene determined by gel permeation chromatography (GPC) is 100,000 to 2,000,000.
  • the lower limit of the weight average molecular weight of the polymer (A) is preferably 120,000, more preferably 150,000.
  • the upper limit of the weight average molecular weight of the polymer (A) is preferably 1,800,000, more preferably 1,600,000.
  • the weight average molecular weight (Mw) of the polymer (A) is within the above range, the polymer (A) is easily dissolved in the liquid medium (C), so that the slurry prepared by mixing with the active material is stabilized.
  • the slurry can also be coated onto the current collector.
  • the binding properties between the active material, solid electrolyte, and filler such as a conductive aid due to the polymer (A) are improved, and an all-solid-state secondary battery with excellent charge/discharge characteristics is easily obtained.
  • the resistance to external forces such as pressing and bending of the electrode plate and solid electrolyte layer during production of an all-solid-state secondary battery is improved.
  • the solubility of the polymer (A) in toluene at 25° C. and 1 atmosphere is preferably 1 g or more per 100 g of toluene.
  • the solubility in toluene of 1 g or more in toluene means that the polymer (A) is soluble in the organic solvent.
  • the surface of the active material is easily coated with the polymer (A), which has excellent flexibility and adhesion, so that the active material does not fall off due to expansion and contraction during charging and discharging. Therefore, it is easy to obtain an electricity storage device that can effectively suppress the storage of electricity and exhibit good charge/discharge durability characteristics. It is also preferable because the stability of the slurry is improved and the applicability of the slurry to the current collector is also improved.
  • the polymer (A) preferably has a first endothermic peak in the temperature range of -80°C to 0°C when measured by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012. In addition to the first endothermic peak, the polymer (A) exhibits a second endothermic peak in the temperature range of 80°C to 150°C when measured by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012. It is more preferable to further have a peak. When the endothermic peak of the polymer (A) in DSC analysis is within the above range, the polymer (A) is preferable because it can impart better flexibility and binding properties to the active material layer.
  • the method for producing the polymer (A) is not particularly limited, but may be, for example, an emulsion polymerization method carried out in the presence of a known emulsifier, chain transfer agent, polymerization initiator, or the like.
  • emulsifiers include higher alcohol sulfate ester salts, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyldiphenyl ether disulfonates, aliphatic sulfonates, aliphatic carboxylates, dehydroabietate, naphthalene sulfonic acid/formalin.
  • Anionic surfactants such as condensates and sulfate ester salts of nonionic surfactants;
  • Nonionic surfactants such as alkyl esters of polyethylene glycol, alkyl phenyl ethers of polyethylene glycol, and alkyl ethers of polyethylene glycol; perfluorobutyl Examples include fluorine-based surfactants such as sulfonates, perfluoroalkyl group-containing phosphate esters, perfluoroalkyl group-containing carboxylates, and perfluoroalkyl ethylene oxide adducts, and 1 selected from these. More than one species can be used.
  • chain transfer agent and polymerization initiator compounds described in Japanese Patent No. 5999399 and the like can be used.
  • the emulsion polymerization method for synthesizing the polymer (A) may be carried out by one-stage polymerization, or may be carried out by multi-stage polymerization of two or more stages.
  • the mixture of the above monomers is mixed in the presence of a suitable emulsifier, chain transfer agent, polymerization initiator, etc., preferably at a temperature of 0 to 80°C, Emulsion polymerization can be performed, preferably with a polymerization time of 4 to 36 hours.
  • each stage of polymerization is preferably set as follows.
  • the proportion of the monomer used in the first stage polymerization is based on the total mass of the monomers (the sum of the mass of the monomer used in the first stage polymerization and the mass of the monomer used in the second stage polymerization). It is preferably in the range of 20 to 99% by mass, more preferably in the range of 25 to 99% by mass.
  • the polymerization conditions at each stage are preferably as follows from the viewpoint of dispersibility of particles of the resulting polymer (A).
  • - First-stage polymerization Preferably a temperature of 0 to 80°C; a polymerization time of preferably 2 to 36 hours; a polymerization conversion rate of preferably 50% by mass or more, more preferably 60% by mass or more.
  • Second stage polymerization preferably a temperature of 0 to 80°C; preferably a polymerization time of 2 to 18 hours.
  • each stage of polymerization is preferably set as follows.
  • the types of monomers used in the second-stage polymerization and their usage ratios may be the same as or different from the monomer types and their usage ratios used in the first-stage polymerization.
  • the types of monomers used in the third stage polymerization and their usage ratios are the types of monomers used in the first stage polymerization and their usage ratios, and the types of monomers used in the second stage polymerization and their usage ratios. may be the same or different.
  • the polymerization conditions at each stage are preferably as follows from the viewpoint of dispersibility of particles of the resulting polymer (A).
  • - First-stage polymerization Preferably a temperature of 0 to 80°C; a polymerization time of preferably 2 to 36 hours; a polymerization conversion rate of preferably 50% by mass or more, more preferably 60% by mass or more.
  • Second stage polymerization preferably a temperature of 0 to 80°C; preferably a polymerization time of 2 to 18 hours.
  • Third stage polymerization preferably a temperature of 0 to 80°C; preferably a polymerization time of 2 to 9 hours.
  • This total solid content concentration is preferably 45% by mass or less, more preferably 40% by mass or less.
  • a neutralizing agent to the polymerization mixture to neutralize it after the emulsion polymerization is completed.
  • the neutralizing agent used here is not particularly limited, but includes, for example, metal hydroxides such as sodium hydroxide and potassium hydroxide; ammonia, and the like.
  • the solidification temperature is not particularly limited, but is preferably 40°C or higher and 90°C or lower, more preferably 45°C or higher and 80°C or lower.
  • the amount of water added to the water-containing crumb during washing with water is not particularly limited, but it effectively reduces the coagulant content (residual amount) in the final binder composition for power storage devices. From the viewpoint that it can be used, it is preferably 150 parts by mass or more and 10,000 parts by mass or less, more preferably 150 parts by mass or more and 5,000 parts by mass or less, based on 100 parts by mass of the polymer contained in the hydrous crumb. be.
  • the number of times of water washing is not particularly limited and may be one time, but preferably two or more times from the viewpoint of reducing the coagulant content (residual amount) in the finally obtained binder composition for power storage devices. It is 8 times or less, more preferably 3 times or more and 10 times or less.
  • the effect of removing the coagulant is small, the increase in the number of steps increases the impact of reduction in manufacturing efficiency.
  • the water-containing crumb that has undergone the above-mentioned washing step is dried to obtain a coagulated dried product containing a polymer and a coagulant.
  • the drying method that can be used in the drying process is not particularly limited, but for example, drying can be performed using a dryer such as a screw type extruder, kneader type dryer, expander dryer, hot air dryer, or vacuum dryer. can. Further, a drying method that combines these methods may also be used. Furthermore, before drying in the drying step, if necessary, the water-containing crumb may be filtered using a sieve such as a rotary screen or a vibrating screen; a centrifugal dehydrator, or the like.
  • the binder composition for a power storage device according to the present embodiment may contain additives other than the above-mentioned components as necessary.
  • additives include polymers other than polymer (A), antioxidants, thickeners, and the like.
  • antioxidants examples include compounds such as phenolic antioxidants, amine antioxidants, quinone antioxidants, organophosphorus antioxidants, sulfur antioxidants, and phenothiazine antioxidants. . Among these, phenolic antioxidants and amine antioxidants are preferred.
  • thickeners include cellulose polymers such as carboxymethylcellulose, methylcellulose, ethylcellulose, and hydroxypropylcellulose; poly(meth)acrylic acid; ammonium salts or alkali metal salts of the cellulose compound or the poly(meth)acrylic acid; Examples include modified polyvinyl alcohol, polyethylene oxide; polyvinylpyrrolidone, polycarboxylic acid, oxidized starch, phosphate starch, casein, various modified starches, chitin, and chitosan derivatives. Among these, cellulose polymers are preferred.
  • Examples of commercially available thickeners include alkali metal salts of carboxymethyl cellulose such as CMC1120, CMC1150, CMC2200, CMC2280, and CMC2450 (all manufactured by Daicel Corporation).
  • the binder composition for an electricity storage device contains a thickener
  • the content of the thickener is 5% by mass or less with respect to 100% by mass of the total solid content of the binder composition for an electricity storage device.
  • the amount is preferably 0.1 to 3% by mass, and more preferably 0.1 to 3% by mass.
  • slurry for power storage devices for all-solid-state secondary batteries (hereinafter also referred to as “slurry for all-solid-state secondary batteries”) and slurry for power storage devices for producing active material layers of electrodes for lithium-ion secondary batteries are available. Slurry (hereinafter also referred to as “slurry for lithium ion secondary battery electrodes”) will be explained separately.
  • the sulfide-based solid electrolyte preferably contains a sulfur atom (S) and a metal element of Group 1 or Group 2 of the periodic table, has ionic conductivity, and has electronic insulation properties.
  • the lithium ion conductivity of the oxide solid electrolyte is preferably 1 ⁇ 10 ⁇ 6 S/cm or more, more preferably 1 ⁇ 10 ⁇ 5 S/cm or more, and particularly preferably 5 ⁇ 10 ⁇ 5 S/cm or more.
  • the negative electrode active material is not particularly limited as long as it can reversibly insert and release lithium ions, etc., but examples include carbonaceous materials, metal oxides such as tin oxide and silicon oxide, lithium alone, lithium aluminum alloys, etc. Examples include lithium alloys, metals that can form alloys with lithium, such as Sn, Si, and In. Among these, carbonaceous materials are preferably used from the viewpoint of reliability, and silicon-containing materials are preferably used from the viewpoint of increasing battery capacity.
  • Silicon-containing materials can store more lithium ions than commonly used graphite and acetylene black. That is, since the amount of lithium ions stored per unit weight increases, the battery capacity can be increased.
  • silicon-containing materials are known to undergo large volume changes as they absorb and release lithium ions, and repeating this expansion and contraction (repeated charging and discharging) increases the durability of the negative electrode active material layer. This may lead to insufficient contact, for example, or a shortened cycle life (battery life).
  • the negative electrode active material layer produced using the slurry for all-solid-state secondary batteries according to this embodiment exhibits high durability (strength) because the binder component follows even if such expansion and contraction are repeated. Therefore, it has the excellent effect of realizing good cycle life characteristics even under high voltage.
  • the average particle size of the negative electrode active material is not particularly limited, but from the viewpoint of increasing the contact area of the solid-solid interface, it is preferably 0.1 ⁇ m to 60 ⁇ m.
  • the above-mentioned pulverizer or classifier can be used.
  • the content ratio of the conductivity imparting agent is preferably 20 parts by mass or less, and 1 to 100 parts by mass, based on 100 parts by mass of the active material. More preferably, the amount is 15 parts by weight, and particularly preferably 2 to 10 parts by weight.
  • the slurry for all-solid-state secondary batteries according to the present embodiment can be manufactured by any method as long as it contains the above-mentioned binder composition for electricity storage devices and solid electrolyte. It may be something that has been done.
  • Preparation of the slurry for an all-solid-state secondary battery is preferably performed at least in part under reduced pressure. This can prevent bubbles from forming in the resulting positive electrode active material layer, negative electrode active material layer, or solid electrolyte layer.
  • the degree of pressure reduction is preferably about 5.0 ⁇ 10 3 to 5.0 ⁇ 10 5 Pa in terms of absolute pressure.
  • positive electrode slurry often contains polyvinylidene fluoride (PVDF) in order to suppress an increase in internal resistance.
  • PVDF polyvinylidene fluoride
  • the slurry for a lithium ion secondary battery electrode according to the present embodiment can suppress an increase in internal resistance even when it contains only the above-mentioned polymer (A) as a polymer component.
  • the slurry for a lithium ion secondary battery electrode according to the present embodiment may contain a polymer other than the polymer (A) or a thickener in order to further suppress an increase in internal resistance.
  • the components contained in the slurry for a lithium ion secondary battery electrode according to this embodiment will be explained below.
  • Binder Composition for Electricity Storage Devices The composition, physical properties, and manufacturing method of the binder composition for electricity storage devices are as described above, so explanations thereof will be omitted.
  • the content ratio of the polymer component in the slurry for a lithium ion secondary battery electrode according to the present embodiment is preferably 0.5 to 10 parts by mass, more preferably 1 to 8 parts by mass, based on 100 parts by mass of the active material. parts, more preferably 1 to 7 parts by weight, particularly preferably 1.5 to 6 parts by weight.
  • the polymer component includes the polymer (A), a polymer other than the polymer (A) that is added as necessary, a thickener, and the like.
  • the active material used in the slurry for a lithium ion secondary battery electrode according to this embodiment includes a positive electrode active material and a negative electrode active material.
  • these include carbon materials, silicon materials, oxides containing lithium atoms, sulfur compounds, lead compounds, tin compounds, arsenic compounds, antimony compounds, aluminum compounds, conductive polymers such as polyacene, A B Y O Z (However, A is an alkali metal or a transition metal, B is at least one selected from transition metals such as cobalt, nickel, aluminum, tin, and manganese, O represents an oxygen atom, and X, Y, and Z are numbers in the range of 1.10>X>0.05, 4.00>Y>0.85, and 5.00>Z>1.5, respectively.) and other complex metal oxides. metal oxides and the like. Specific examples of these include compounds described in Japanese Patent No. 5999399 and the like.
  • the slurry for lithium ion secondary battery electrodes according to the present embodiment can be used when producing either a positive electrode or a negative electrode, it is particularly preferable to use it for a positive electrode.
  • M is at least one selected from the group consisting of Mg, Ti, V, Nb, Ta, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Ga, Ge, and Sn.
  • A is at least one kind selected from the group consisting of Si, S, P, and V, and x is a number satisfying the relationship 0 ⁇ x ⁇ 1.
  • the value of x in the general formula (1) is selected according to the valences of M and A so that the valence of the general formula (2) as a whole becomes zero.
  • the average particle diameter of the olivine-type lithium-containing phosphoric acid compound is preferably in the range of 1 to 30 ⁇ m, more preferably in the range of 1 to 25 ⁇ m, and particularly preferably in the range of 1 to 20 ⁇ m.
  • the active material layer may contain active materials exemplified below.
  • a conductive polymer such as polyacene ;
  • A represents an oxygen atom, and
  • X, Y, and Z are numbers in the range of 1.10>X>0.05, 4.00>Y>0.85, and 5.00>Z>1.5, respectively.
  • Examples include composite metal oxides represented by and other metal oxides.
  • Examples of the composite metal oxide include lithium cobalt oxide, lithium nickel oxide, lithium manganate, ternary nickel cobalt lithium manganate, and the like.
  • the lithium ion secondary battery electrode produced using the lithium ion secondary battery electrode slurry according to the present embodiment exhibits good electrical characteristics even when an oxide containing lithium atoms is used as the positive electrode active material. Can be done. The reason for this is that the polymer (A) can strongly bind oxides containing lithium atoms, and at the same time maintain the state in which oxides containing lithium atoms are firmly bound even during charging and discharging. It is believed that there is.
  • the active material when producing a negative electrode, it is preferable that the active material contains a silicon material and/or a carbon material among the above-mentioned active materials, and a mixture of a silicon material and a carbon material is more preferable.
  • Silicon material has a large lithium storage capacity per unit weight compared to other active materials, so it can increase the storage capacity of the resulting power storage device, and as a result, the output and energy density of the power storage device can be increased. can do.
  • carbon materials have a smaller volume change due to charging and discharging than silicon materials, so by using a mixture of silicon materials and carbon materials as the negative electrode active material, the effect of volume changes of silicon materials can be alleviated. , it is possible to further improve the adhesion ability between the active material layer and the current collector.
  • silicon (Si) When silicon (Si) is used as an active material, while silicon has a high capacity, it undergoes a large volume change when occluding lithium. For this reason, the silicon material becomes finely powdered through repeated expansion and contraction, causing peeling from the current collector and separation of the active materials from each other, and the conductive network inside the active material layer is likely to be disrupted. Due to this property, the charge/discharge durability characteristics of the electricity storage device deteriorate extremely in a short period of time.
  • the electricity storage device electrode produced using the slurry for lithium ion secondary battery electrodes according to the present embodiment does not have the above-mentioned problems even when silicon material is used, and has good electrical performance. Characteristics can be shown. The reason for this is that the polymer (A) can strongly bind the silicon material, and at the same time, even if the silicon material expands in volume by occluding lithium, the polymer (A) expands and contracts, causing the silicon to bind. This is thought to be because the materials can be maintained in a strongly bonded state.
  • the content of the silicon material in 100% by mass of the active material is preferably 1% by mass or more, more preferably 2 to 50% by mass, even more preferably 3 to 45% by mass, and 10% by mass. It is particularly preferable to set the content to 40% by mass.
  • the content of the silicon material in 100% by mass of the active material is within the above range, an electricity storage device with an excellent balance between improvement in the output and energy density of the electricity storage device and charge/discharge durability characteristics can be obtained.
  • the shape of the active material is preferably particulate.
  • the average particle diameter of the active material is preferably 0.1 to 100 ⁇ m, more preferably 1 to 20 ⁇ m.
  • the slurry for a lithium ion secondary battery electrode according to the present embodiment may optionally contain a polymer other than the polymer (A), a thickener, a liquid medium, and a conductivity imparting agent. , pH adjusters, corrosion inhibitors, antioxidants, cellulose fibers, and other components may be added. Polymers other than polymer (A) and thickeners should be appropriately selected from the compounds exemplified in the section "1.4. Other additives" above and used for the same purpose and content ratio. Can be done.
  • a liquid medium may be further added to the slurry for a lithium ion secondary battery electrode according to the present embodiment.
  • the liquid medium to be added may be the same type as the liquid medium (C) contained in the binder composition for electricity storage devices, or may be different from the liquid medium (C) in the above "1.3. Liquid medium (C)". It is preferable to use a liquid medium selected from among the liquid media exemplified in Section 3.
  • the content ratio of the liquid medium (including the amount brought in from the binder composition for power storage devices) in the slurry for the lithium ion secondary battery electrode according to the present embodiment is determined by the solid content concentration in the slurry (the content of the liquid medium in the slurry other than the liquid medium in the slurry).
  • the ratio of the total mass of the components to the total mass of the slurry is preferably 30 to 70% by mass, more preferably 40 to 60% by mass.
  • a conductive additive may be further added to the slurry for a lithium ion secondary battery electrode according to the present embodiment for the purpose of imparting conductivity and buffering changes in volume of the active material due to inflow and outflow of lithium ions. good.
  • a pH adjuster may be further added to the slurry for a lithium ion secondary battery electrode according to the present embodiment for the purpose of suppressing corrosion of the current collector.
  • pH adjusting agent examples include hydrochloric acid, phosphoric acid, sulfuric acid, acetic acid, formic acid, ammonium phosphate, ammonium sulfate, ammonium acetate, ammonium formate, ammonium chloride, sodium hydroxide, potassium hydroxide, etc.
  • sulfuric acid, ammonium sulfate, sodium hydroxide, and potassium hydroxide are preferred.
  • a corrosion inhibitor may be further added to the slurry for a lithium ion secondary battery electrode according to the present embodiment for the purpose of suppressing corrosion of the current collector depending on the type of active material.
  • Corrosion inhibitors include ammonium metavanadate, sodium metavanadate, potassium metavanadate, ammonium metatungstate, sodium metatungstate, potassium metatungstate, ammonium paratungstate, sodium paratungstate, potassium paratungstate, molybdic acid.
  • Ammonium, sodium molybdate, potassium molybdate, etc. can be mentioned, and among these, ammonium paratungstate, ammonium metavanadate, sodium metavanadate, potassium metavanadate, and ammonium molybdate are preferable.
  • Cellulose fibers may be further added to the slurry for a lithium ion secondary battery electrode according to this embodiment.
  • As the cellulose fiber known ones can be used. By adding cellulose fibers, the adhesion of the active material to the current collector may be improved. It is thought that by fibrous cellulose fibers binding adjacent active materials to each other through line adhesion or line contact, it is possible to prevent the active materials from falling off and to improve the adhesion to the current collector.
  • the slurry for lithium ion secondary battery electrodes according to the present embodiment can be prepared by any method as long as it contains the above-mentioned binder composition for power storage devices and active material. It may be a manufactured product. From the viewpoint of producing a slurry with better dispersibility and stability more efficiently and at a lower cost, active materials and optional additive components used as necessary are added to the binder composition for power storage devices, and these are mixed. It is preferable to manufacture by.
  • a specific manufacturing method includes, for example, the method described in Japanese Patent No. 5999399.
  • Electrolyte sheet for all-solid secondary batteries, electrodes for all-solid secondary batteries, and all-solid secondary batteries 3.1.
  • Electrolyte sheet for all-solid-state secondary batteries A solid electrolyte sheet according to one embodiment of the present invention has a layer formed by applying and drying the above slurry for all-solid-state secondary batteries on a base material.
  • the solid electrolyte sheet according to the present embodiment can be produced by, for example, applying the slurry for an all-solid-state secondary battery onto a film serving as a base material using a blade method (for example, a doctor blade method), a calendar method, a spin coating method, a dip coating method, or the like. It can be manufactured by applying by an inkjet method, an offset method, a die coating method, a spray method, or the like, drying to form a layer, and then peeling off the film.
  • a film for example, a general film such as a PET film subjected to mold release treatment can be used.
  • Electrolyte sheets can also be molded.
  • the slurry for all-solid-state secondary batteries is applied so that the layer thickness is preferably in the range of 1 to 500 ⁇ m, more preferably in the range of 1 to 100 ⁇ m. It is preferable to do so.
  • the thickness of the layer is within the above range, conductive ions such as lithium ions move easily, resulting in high battery output. Further, when the thickness of the layer is within the above range, the entire battery can be made thinner, so that the capacity per unit volume can be increased.
  • the solid electrolyte sheet contains a positive electrode active material and a solid electrolyte
  • the solid electrolyte sheet has a function as a positive electrode active material layer.
  • the solid electrolyte sheet contains a negative electrode active material and a solid electrolyte
  • the solid electrolyte sheet has a function as a negative electrode active material layer.
  • the solid electrolyte sheet does not contain a positive electrode active material and a negative electrode active material but contains a solid electrolyte
  • the solid electrolyte sheet has a function as a solid electrolyte layer.
  • Electrode for all-solid-state secondary batteries includes a current collector, and the above-mentioned slurry for all-solid-state secondary batteries is applied and dried on the surface of the current collector. and an active material layer formed by.
  • Such an electrode for an all-solid-state secondary battery is made by applying the above-mentioned slurry for an all-solid-state secondary battery to the surface of a current collector such as metal foil to form a coating film, and then drying the coating film to form an active material. It can be manufactured by forming layers.
  • the electrode for an all-solid-state secondary battery manufactured in this way has an active material containing the above-mentioned polymer (A), solid electrolyte, and active material, and optional components added as necessary, on a current collector. Since the material layers are bonded together, it has excellent flexibility, abrasion resistance, and resistance to powder falling off, and also exhibits good charge-discharge durability characteristics.
  • the current collectors for the positive and negative electrodes it is preferable to use an electron conductor that does not undergo chemical changes.
  • As the current collector of the positive electrode aluminum, stainless steel, nickel, titanium, alloys thereof, etc., and aluminum or stainless steel whose surface is treated with carbon, nickel, titanium, or silver are preferable, and among these, Aluminum and aluminum alloys are more preferred.
  • As the current collector of the negative electrode aluminum, copper, stainless steel, nickel, titanium, and alloys thereof are preferable, and aluminum, copper, and copper alloys are more preferable.
  • the shape of the current collector is usually in the form of a film sheet, but nets, punched objects, lath bodies, porous bodies, foam bodies, molded bodies of fiber groups, etc. can also be used.
  • the thickness of the current collector is not particularly limited, but is preferably 1 ⁇ m to 500 ⁇ m. Further, it is also preferable that the surface of the current collector is made uneven by surface treatment.
  • a doctor blade method, a reverse roll method, a comma bar method, a gravure method, an air knife method, or the like can be used as a means for applying the slurry for an all-solid-state secondary battery onto a current collector.
  • the processing temperature is preferably 20 to 250°C, more preferably 50 to 150°C, and the processing time is 1 to 120 minutes.
  • the duration is preferably 5 to 60 minutes, and more preferably 5 to 60 minutes.
  • the active material layer formed on the current collector may be compressed by pressing.
  • a means for pressing a high-pressure super press, a soft calender, a 1-ton press, etc. can be used. Pressing conditions can be set as appropriate depending on the processing machine used.
  • the active material layer thus formed on the current collector has, for example, a thickness of 40 to 100 ⁇ m and a density of 1.3 to 2.0 g/cm 3 .
  • the electrode for an all-solid-state secondary battery manufactured in this way is an electrode for an all-solid-state secondary battery composed of a solid electrolyte layer sandwiched between a pair of electrodes, specifically an electrode for an all-solid-state secondary battery. It is suitably used as a positive electrode and/or a negative electrode. Moreover, the solid electrolyte layer formed using the above-mentioned slurry for an all-solid-state secondary battery is suitably used as a solid electrolyte layer for an all-solid-state secondary battery.
  • All-solid-state secondary battery can be manufactured using a known method. Specifically, the following manufacturing method can be used.
  • a slurry for an all-solid secondary battery positive electrode containing a solid electrolyte and a positive electrode active material is applied onto a current collector and dried to form a positive electrode active material layer, thereby producing a positive electrode for an all-solid secondary battery.
  • a slurry for an all-solid-state secondary battery solid electrolyte layer containing a solid electrolyte is applied to the surface of the positive electrode active material layer of the all-solid-state secondary battery positive electrode and dried to form a solid electrolyte layer.
  • an all-solid secondary battery negative electrode slurry containing a solid electrolyte and a negative electrode active material is applied onto the surface of the solid electrolyte layer and dried to form a negative electrode active material layer.
  • a negative electrode side current collector metal foil
  • a solid electrolyte sheet is produced on a release PET film and bonded onto the previously produced positive electrode for an all-solid-state secondary battery or negative electrode for an all-solid-state secondary battery. Thereafter, by peeling off the release PET, a desired all-solid-state secondary battery structure can be obtained.
  • each of the above compositions may be applied by a conventional method. At this time, it is preferable to perform a heat treatment after each coating of the slurry for the all-solid secondary battery positive electrode, the slurry for the all-solid secondary battery solid electrolyte layer, and the slurry for the all-solid secondary battery negative electrode.
  • the heating temperature is preferably higher than the glass transition temperature of the polymer (A).
  • the temperature is preferably 30°C or higher, more preferably 60°C or higher, and most preferably 100°C or higher.
  • the upper limit is preferably 300°C or less, more preferably 250°C or less.
  • the pressurizing pressure is preferably 5 kN/cm 2 or more, more preferably 10 kN/cm 2 or more, and particularly preferably 20 kN/cm 2 or more.
  • the discharge capacity refers to a value per weight of active material of an electrode, and in the case of a half cell, a value per weight of active material of a negative electrode.
  • the electrode for a lithium ion secondary battery manufactured in this way has an active material layer on the surface of the current collector containing the above-mentioned polymer (A), an active material, and optional components added as necessary. Since it is made by binding together, it has excellent repeated charging and discharging characteristics as well as excellent charging and discharging durability characteristics.
  • the current collector is not particularly limited as long as it is made of a conductive material, and examples include the current collector described in Japanese Patent No. 5999399.
  • the content of silicon element in 100% by mass of the active material layer is preferably 1 to 30% by mass, and 2% by mass. It is more preferably 20% by weight, and particularly preferably 3% to 10% by weight.
  • the content ratio of silicon element in the active material layer is within the above range, the storage capacity of a lithium ion secondary battery manufactured using the active material layer is improved, and the active material layer has a uniform distribution of silicon element. is obtained.
  • the content of silicon element in the active material layer can be measured, for example, by the method described in Japanese Patent No. 5999399.
  • Lithium ion secondary battery A lithium ion secondary battery according to an embodiment of the present invention is equipped with the above-mentioned lithium ion secondary battery electrode, further contains an electrolyte, and is manufactured using parts such as a separator according to a conventional method. can be manufactured.
  • a specific manufacturing method includes, for example, stacking a negative electrode and a positive electrode with a separator in between, rolling or folding them according to the shape of the battery, storing them in a battery container, and injecting an electrolyte into the battery container.
  • An example of this is a method of sealing the container.
  • the shape of the battery can be any appropriate shape, such as a coin shape, a cylindrical shape, a square shape, or a laminate shape.
  • the electrolyte may be liquid or gel, and depending on the type of active material, one may be selected from known electrolytes used in lithium ion secondary batteries that effectively exhibits battery functions.
  • the electrolyte can be a solution of an electrolyte dissolved in a suitable solvent. Examples of such electrolytes and solvents include compounds described in Japanese Patent No. 5999399 and the like.
  • known members for lithium ion secondary batteries can be used as the members other than the binder composition for an electricity storage device.
  • binder composition for power storage device A polymer (A1) dispersion was obtained by one-stage polymerization as shown below.
  • a monomer mixture consisting of 200 parts by mass of water, 50 parts by mass of 1,3-butadiene, and 50 parts by mass of styrene, 0.5 parts by mass of tert-dodecyl mercaptan as a chain transfer agent, and alkyldiphenyl ether as an emulsifier were placed in a reactor.
  • the polymer (A1) obtained above was added to anisole and stirred overnight to prepare a binder composition for a power storage device in which the polymer (A1) was dissolved in anisole.
  • the content of the polymer (A1) was adjusted to be 10% by mass when the entire binder composition for an electricity storage device is 100% by mass.
  • Example 2 ⁇ Examples 2, 4, 6 to 12, Comparative Examples 1 to 5>
  • Example 2 the same procedure as in Example 1 was carried out except that the types and amounts of monomers were as shown in Tables 1 to 2 below, respectively.
  • Each polymer was synthesized by polymerization, and each binder composition for an electricity storage device was obtained in the same manner as in Example 1.
  • a polymer (A3) dispersion was obtained by two-stage polymerization as shown below.
  • a reactor was charged with a monomer mixture consisting of 200 parts by mass of water, 60 parts by mass of 1,3-butadiene, 10 parts by mass of styrene, 2 parts by mass of methacrylic acid, and 3 parts by mass of methyl methacrylate, and tert- as a chain transfer agent.
  • the polymer (A3) obtained above was added to anisole and stirred overnight to prepare a binder composition for a power storage device in which the polymer (A3) was dissolved in anisole.
  • the content of the polymer (A3) was set to 10% by mass when the entire binder composition for an electricity storage device was 100% by mass.
  • Example 5 ⁇ Examples 5, 13, 14>
  • each polymer was synthesized by two-stage polymerization in the same manner as in Example 3, except that the types and amounts of monomers were as shown in Tables 1 and 2 below, respectively. Then, in the same manner as in Example 3, binder compositions for each power storage device were obtained.
  • a rotation-revolution mixer Alwatori Rentaro ARV-310, manufactured by THINKY
  • ⁇ Preparation of slurry for solid electrolyte layer of all-solid-state secondary battery> 100 parts by mass of sulfide glass consisting of Li 2 S and P 2 S 5 (Li 2 S/P 2 S 5 75 mol%/25 mol%, average particle size 5 ⁇ m) as a solid electrolyte, and the binder for power storage devices prepared above.
  • the composition was mixed with 2 parts by mass equivalent to the solid content, and anisole was further added as a liquid organic medium to adjust the solid content concentration to 55%. ) for 10 minutes to prepare a slurry for an all-solid-state secondary battery solid electrolyte layer.
  • ⁇ Preparation of slurry for all-solid-state secondary battery negative electrode> 65 parts by mass of artificial graphite (average particle size: 20 ⁇ m) as a negative electrode active material, sulfide glass consisting of Li 2 S and P 2 S 5 as a solid electrolyte (Li 2 S / P 2 S 5 75 mol% / 25 mol%, 35 parts by mass (average particle diameter 5 ⁇ m) and 2 parts by mass equivalent to the solid content of the binder composition for power storage devices prepared above were mixed, and anisole was further added as a liquid organic medium to adjust the solid content concentration to 65%. After that, the mixture was mixed for 10 minutes using a rotation-revolution mixer (Awatori Rentaro ARV-310, manufactured by THINKY) to prepare a slurry for an all-solid-state secondary battery negative electrode.
  • a rotation-revolution mixer Alwatori Rentaro ARV-310, manufactured by THINKY
  • the slurry for solid electrolyte for all-solid-state secondary batteries prepared above was applied onto a release PET film using a doctor blade method, anisole was evaporated under reduced pressure at 120°C, and the slurry was dried for 3 hours to a thickness of 0. A 1 mm solid electrolyte layer was prepared.
  • the slurry for the all-solid-state secondary battery negative electrode prepared above was applied onto a stainless steel foil using a doctor blade method, the anisole was evaporated under reduced pressure at 120°C, and the anode was dried for 3 hours to form a negative electrode with a thickness of 0.1 mm.
  • a negative electrode for an all-solid-state secondary battery on which an active material layer was formed was produced.
  • - 3 points If the number of broken particle traces is 6 or more and 10 or less, there are few coating defects due to residual emulsifier, which is good.
  • - 2 points If the number of broken particle traces is 11 or more and 15 or less, there will be some coating defects due to the residual emulsifier, making it difficult to use.
  • - 1 point If the number of broken particle traces is 16 or more, there are many coating defects due to residual emulsifier, and the product cannot be used.
  • Lithium ion conductivity is 0.5 x 10 -4 S/cm or more and less than 0.8 x 10 -4 S/cm.
  • - 3 points Lithium ion conductivity is 0.2 x 10 -4 S/cm or more and less than 0.5 x 10 -4 S/cm.
  • ⁇ 2 points Lithium ion conductivity is 0.1 ⁇ 10 ⁇ 4 S/cm or more and less than 0.2 ⁇ 10 ⁇ 4 S/cm.
  • ⁇ 1 point Less than 0.1 ⁇ 10 ⁇ 4 S/cm.
  • a negative electrode half cell was produced by stacking the two layers so that they were arranged between the laminates (1 mm).
  • a charge/discharge test was conducted on the obtained negative electrode half cell. Charging and discharging were performed at a rate of 0.1C in a potential range of 0.88 to -0.57V (vs. Li-In).
  • Capacity retention rate after 20 cycles was calculated using the following formula (4).
  • the evaluation criteria are as follows. The results are shown in Tables 1 and 2 below.
  • Capacity retention rate after 20 cycles (%) (B/A) x 100 (4)
  • X represents the time required to charge or discharge the rated capacity of electricity.
  • 0.1C means that the current value is rated capacity (Ah)/10 (h).
  • Capacity retention rate is 95% or more and 100% or less.
  • Capacity retention rate is 90% or more and less than 95%.
  • ⁇ 3 points Capacity retention rate is 85% or more and less than 90%.
  • ⁇ 2 points Capacity retention rate is 80% or more and less than 85%.
  • ⁇ 1 point Capacity retention rate is less than 80%.
  • Example 15 and 16 Comparative Examples 6 to 8 In Example 15, 2 parts by mass of the polymer (A1) synthesized in Example 1 was used as the negative electrode binder, and 2 parts by mass of the polymer (A3) synthesized in Example 3 was used as the positive electrode binder. The same evaluation as in Example 1 was performed. Further, for Example 16 and Comparative Examples 6 to 8, the same evaluation as in Example 1 was performed except that the polymers listed in Table 3 below were used. The results are shown in Table 3 below.
  • Tables 1 to 2 below show the polymer compositions, physical property measurement results, and evaluation results used in Examples 1 to 14 and Comparative Examples 1 to 5. shows.
  • Table 3 below shows the polymer component compositions used in Examples 15 and 16 and Comparative Examples 6 to 8, and the evaluation results. Note that the numerical values representing the polymer composition shown in Tables 1 to 3 below represent parts by mass.
  • a slurry containing the binder composition for an electricity storage device, an active material, and a solid electrolyte of the present invention is used as a slurry for an all-solid-state secondary battery.
  • the active material layer formed with the slurry has a good surface condition and excellent lithium ion conductivity, and when measuring peel strength, the active material layer itself becomes brittle and the active material and solid electrolyte No shedding or cracking occurred, and it was confirmed that the binder had sufficient binding properties between both the active material and the solid electrolyte.
  • the binder composition for power storage devices of the present invention electrodes for all-solid-state secondary batteries with excellent surface conditions, adhesion, and lithium ion conductivity can be produced, and the cycle life of all-solid-state secondary batteries can be improved. It was found that the characteristics could be improved.
  • binder composition for power storage devices The polymers synthesized above shown in Tables 4 to 6 below were added to N-methyl-2-pyrrolidone (NMP), and the polymers were stirred overnight. A binder composition for a power storage device was prepared by dissolving it in NMP. Here, the content of the polymer was set to 8% by mass when the entire binder composition for an electricity storage device was 100% by mass.
  • LFP (trade name "DY-1", manufactured by Tokukata Natmeisha) as a positive electrode active material 100 Parts by mass, 9 parts by mass of acetylene black, 1 part by mass of a thickener (trade name "CMC2200", manufactured by Daicel Corporation), and 74 parts by mass of NMP were added to prepare a slurry with a solid content concentration of approximately 50%. The mixture was stirred at 60 rpm for 1 hour. Note that LFP is an example of a positive electrode active material.
  • - 3 points If the number of broken particle traces is 6 or more and 10 or less, there are few coating defects due to residual emulsifier, which is good.
  • - 2 points If the number of broken particle traces is 11 or more and 15 or less, there will be some coating defects due to the residual emulsifier, making it difficult to use.
  • - 1 point If the number of broken particle traces is 16 or more, there are many coating defects due to residual emulsifier, and the product cannot be used.
  • ⁇ Preparation of negative electrode for lithium ion secondary battery> The slurry for lithium ion secondary battery negative electrode prepared above was uniformly applied to the surface of a current collector made of copper foil with a thickness of 20 ⁇ m using a doctor blade method so that the film thickness after drying was 80 ⁇ m. It was dried at °C for 20 minutes. Thereafter, a negative electrode for a lithium ion secondary battery was obtained by pressing using a roll press machine so that the density of the formed film (negative electrode active material layer) was 1.9 g/cm 3 .
  • the negative electrode for a lithium ion secondary battery produced above is punched and molded into a circular shape with a diameter of 16.16 mm. Co., Ltd., trade name "HS Flat Cell”).
  • a separator made of a polypropylene porous membrane punched into a circular shape with a diameter of 24 mm was placed on top of the negative electrode for a lithium ion secondary battery.
  • the positive electrode for lithium ion secondary battery produced above was punched into a circular shape with a diameter of 15.95 mm and placed on top of the separator.
  • a lithium ion secondary battery was assembled by closing and sealing the exterior body of the bipolar coin cell with screws.
  • the time point was defined as the completion of charging (cutoff). Thereafter, discharging was started at a constant current (1.0 C), and the time when the voltage reached 2.5 V was defined as the completion of discharging (cutoff), and the discharge capacity of the first cycle was calculated. Charging and discharging was repeated 100 times in this manner. After repeating charging and discharging 100 times, charging and discharging were performed in the same manner as in the 0th cycle, and the 101st discharge capacity was evaluated. The rate of increase in resistance was calculated using the following formula (5), and evaluated using the following criteria. The results are shown in Tables 4 to 5 below.
  • Resistance increase rate (%) (101st cycle discharge capacity - 100th cycle discharge capacity) / (0th cycle discharge capacity - 1st cycle discharge capacity) x 100 (5) (Evaluation criteria) - 5 points: resistance increase rate is 100% or more and less than 110%.
  • ⁇ 4 points Resistance increase rate is 110% or more and less than 120%.
  • ⁇ 3 points Resistance increase rate is 120% or more and less than 130%.
  • ⁇ 2 points Resistance increase rate is 130% or more and less than 140%.
  • - 1 point resistance increase rate is 140% or more and less than 150%.
  • ⁇ 0 point resistance increase rate is 150% or more.
  • Capacity retention rate (%) (Discharge capacity at 100th cycle)/(Discharge capacity at 1st cycle) (6) (Evaluation criteria)
  • ⁇ 1 point Capacity retention rate is 75% or more and less than 80%.
  • Example 31 12.5 parts by mass of a binder composition for an electricity storage device containing the polymer (A5) synthesized in Example 5 (solid content equivalent: 8% by mass, as the polymer (A5) obtained above) Evaluation was the same as in Example 21, except that NMP was adjusted and added so that the solid content concentration of the slurry for lithium ion secondary battery positive electrode was 50%. was carried out. Further, in Examples 32 and 33, the same evaluation as in Example 21 was performed except that the polymers listed in Table 6 below were used.
  • Tables 4 to 5 below show the polymer compositions, physical property measurement results, and evaluation results used in Examples 17 to 30 and Comparative Examples 9 to 13. shows.
  • Table 6 below shows the composition of the polymer components used in Examples 31 to 33 and the results of each evaluation. Note that the numerical values representing the polymer composition shown in Tables 4 to 5 below represent parts by mass.
  • a slurry containing the binder composition for a power storage device of the present invention and an active material is used as a slurry for a lithium ion secondary battery electrode.
  • the active material layer formed with the slurry has a good surface condition, and when measuring peel strength, the active material layer itself becomes brittle and the active material or solid electrolyte falls off or cracks occur. It was confirmed that the binder had sufficient binding properties between both the active material and the solid electrolyte. Therefore, by using the binder composition for power storage devices of the present invention, electrodes for lithium ion secondary batteries with excellent surface conditions and adhesion can be produced, and the cycle life characteristics of lithium ion secondary batteries can be improved. Understood.
  • the present invention is not limited to the above-described embodiments, and various modifications are possible.
  • the present invention includes configurations that are substantially the same as those described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objectives and effects).
  • the present invention includes configurations in which non-essential parts of the configurations described in the above embodiments are replaced with other configurations.
  • the present invention also includes configurations that have the same effects or can achieve the same objectives as the configurations described in the above embodiments.
  • the present invention also includes a configuration in which known technology is added to the configuration described in the above embodiments.

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Abstract

L'invention fournit une composition de liant pour dispositif d'accumulation qui permet de fabriquer une électrode de dispositif d'accumulation excellente en termes d'état de surface, d'adhérence et de conductivité ionique, et qui permet d'améliorer les caractéristiques de cycle de vie d'un dispositif d'accumulation.　La composition de liant pour dispositif d'accumulation de l'invention comprend un polymère (A), et ３０ à ３００００ｐｐｍ d'un émulsifiant pour la masse totale de polymère (A). Lorsque le total des unités de répétition contenues dans ledit polymère (A) est égal à 100% en masse, alors ledit polymère (A) comprend 50 à 99% en masse d'une unité de répétition (a1) dérivée d'un composé diène conjugué, et １ à ５０% en masse d'une unité de répétition (a2) dérivée d'un composé vinyle aromatique. La masse moléculaire moyenne en poids (Mw) dudit polymère (A) est comprise entre １０００００ et ２００００００.
PCT/JP2023/021706 2022-06-13 2023-06-12 Composition de liant pour dispositif d'accumulation, bouillie pour batterie secondaire entièrement solide, batterie secondaire entièrement solide ainsi que procédé de fabrication associé, feuille d'électrolyte solide pour batterie secondaire entièrement solide ainsi que procédé de fabrication associé, bouillie pour électrode de batterie secondaire au lithium-ion, électrode pour batterie secondaire au lithium-ion, et batterie secondaire au lithium-ion WO2023243590A1 (fr)

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JP2021182534A (ja) * 2020-05-20 2021-11-25 住友化学株式会社 非水電解液二次電池用接着セパレータおよびその製造方法

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