Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
  • H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
• • 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
  • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
  • H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
• • 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 an electrolyte composition, a cured electrolyte obtained by curing the composition, an electrode, and a secondary battery.
• Patent Document 1 discloses an electrolyte composition that contains an alkali metal salt, a photo- and/or thermosetting monomer, and a salt dissociator, and the content of the alkali metal salt is 50 mass% or more relative to 100 mass% of the total amount of the alkali metal salt, the photo- and/or thermosetting monomer, and the salt dissociator.
• the electrolyte membrane obtained by curing the electrolyte composition disclosed in Patent Document 1 above is subject to short-circuiting due to the growth of alkali metal dendrites in a current test conducted over multiple cycles, raising concerns about insufficient membrane strength, and so there is room for improvement.
• the present invention was made in consideration of these points, and its purpose is to improve the film strength of the electrolyte cured material as much as possible while maintaining high lithium ion conductivity.
• the electrolyte composition according to the present invention is an electrolyte composition containing a fluoropolymer, a photo- and/or thermosetting monomer, an alkali metal salt, and a salt dissociator, and is characterized in that the total amount of the fluoropolymer and the monomer is 10 mass% or more based on the total amount of the fluoropolymer, the monomer, the alkali metal salt, and the salt dissociator.
• the content of the fluoropolymer may be 70% by mass or more based on the total amount of the fluoropolymer and the monomer.
• the alkali metal salt may include a lithium salt represented by the following formula (1): LiN( SO2R1 )( SO2R2 ) ( 1 ) ( R1 and R2 each represent a fluorine atom or a fluoroalkyl group having 1 to 3 carbon atoms.)
• the above fluoropolymer may contain vinylidene fluoride as a structural unit.
• the above monomer may contain a urethane bond as a constituent unit.
• the salt dissociator may include at least one of a sulfonyl compound, a carbonate compound, and a nitrile compound.
• the salt dissociating agent may contain a sulfonyl compound.
• the cured electrolyte material according to the present invention is obtained by curing the electrolyte composition having the above-mentioned structure, and is characterized in that the cured electrolyte material has a lithium ion conductivity of 2.1 ⁇ 10 ⁇ 4 (S/cm) or more.
• the electrode according to the present invention is characterized in that it is formed using the electrolyte composition having the above-mentioned configuration.
• the secondary battery according to the present invention is characterized in that it is formed using the electrolyte cured material and/or the electrodes having the above-mentioned configuration.
• the electrolyte contains a fluoropolymer, a photo- and/or thermosetting monomer, an alkali metal salt, and a salt dissociator, and the total amount of the fluoropolymer and monomer is 10 mass% or more based on the total amount of the fluoropolymer, monomer, alkali metal salt, and salt dissociator, so that the film strength of the electrolyte cured material can be improved as much as possible while maintaining high lithium ion conductivity.
• the electrolyte composition of the present embodiment includes a fluorine-based polymer, a monomer having photo- and/or thermosetting properties, an alkali metal salt, and a salt dissociator.
• the total amount of the fluorine-based polymer and the monomer having photo- and/or thermosetting properties is preferably 10% by mass or more, more preferably 15% by mass or more, and the upper limit is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less, based on the total amount of the fluorine-based polymer, the monomer having photo- and/or thermosetting properties, the alkali metal salt, and the salt dissociator.
• the total amount of the fluorine-based polymer and the monomer having photo- and/or thermosetting properties is preferably 5% by mass or more, more preferably 10% by mass or more, and the upper limit is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less, based on the entire electrolyte composition (total amount of the components constituting the electrolyte composition of this embodiment is 100% by mass), from the viewpoint of improving the breaking strength.
• the content of the fluorine-based polymer is preferably 70% by mass or more based on the total amount of the fluorine-based polymer and the monomer having photo- and/or thermosetting properties.
• the electrolyte cured product obtained by curing the electrolyte composition of this embodiment has an ion conductivity of 2.1 ⁇ 10 ⁇ 4 (S/cm) or more.
• the alkali metal salt is not particularly limited, and examples of the alkali metal constituting the alkali metal salt include lithium, sodium, potassium, rubidium, cesium, and francium. Preferred are lithium, sodium, and potassium, and more preferred is lithium.
• alkali metal salts of fluorosulfonic acid such as LiFSO3
• alkali metal salts of trifluoromethanesulfonic acid such as LiCF3SO3
• imide-based alkali metal salts such as LiN( FSO2 ) 2
• alkali metal salts of perfluoroalkanesulfonylmethides such as LiC( CF3SO2 ) 3
• fluorophosphates such as LiPFa ( CmF2m +1 ) 6-a (0 ⁇ a ⁇ 6, 1 ⁇ m ⁇ 2)
• alkali metal salts of perchloric acid such as LiClO4
• fluoroborates such as LiBFb ( CnF2n +1 ) 4-b (0 ⁇ b ⁇ 4, 1 ⁇ n ⁇ 2)
• alkali metal salts of oxalatoborates such as LiBOB
• cyanoborates such as lithium tetracyanoborate, LiAsF6 , LiI
• the alkali metal salt preferably includes an imide-based alkali metal salt such as LiN(FSO 2 ) 2 , and more preferably includes a lithium salt represented by the following formula (1) (hereinafter also referred to as a "sulfonylimide compound").
• the fluoroalkyl group having 1 to 3 carbon atoms in R1 and R2 may be a hydrocarbon group having 1 to 3 carbon atoms in which at least one hydrogen atom has been substituted with a fluorine atom.
• Specific examples include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a fluoroethyl group, a difluoroethyl group, a trifluoroethyl group, and a pentafluoroethyl group.
• R1 and R2 are preferably a fluorine atom, a trifluoromethyl group, or a pentafluoroethyl group, more preferably a fluorine atom or a trifluoromethyl group, and most preferably a fluorine atom.
• sulfonylimide compounds include lithium bis(fluorosulfonyl)imide (LiN(FSO 2 ) 2 , hereinafter also referred to as "LiFSI”), lithium bis(trifluoromethylsulfonyl)imide (LiN(CF 3 SO 2 ) 2 , hereinafter also referred to as "LiTFSI”), lithium (fluorosulfonyl)(methylsulfonyl)imide, lithium (fluorosulfonyl)(ethylsulfonyl)imide, lithium (fluorosulfonyl)(trifluoromethylsulfonyl)imide, lithium (fluorosulfonyl)(pentafluoroethylsulfonyl)imide, lithium (fluorosulfonyl)(heptafluoropropylsulfonyl)imide, lithium bis(pentafluor
• the compound represented by the above formula (1 ) is preferably LiN( FSO2 ) 2 , LiN( CF3SO2 ) 2 , or LiPF6 , more preferably LiN( FSO2 ) 2 or LiN( CF3SO2 ) 2 , and most preferably LiN( FSO2 ) 2 .
• the sulfonylimide compound may be a commercially available product, or may be synthesized by a conventionally known method.
• the method for synthesizing the sulfonylimide compound is not particularly limited, and any conventionally known method may be used. For example, methods described in WO 2011/149095, JP 2014-201453 A, JP 2010-168249 A, JP 2010-168308 A, JP 2010-189372 A, WO 2011/065502 A, JP-T-8-511274 A, WO 2012/108284 A, WO 2012/117961 A, WO 2012/118063 A, JP 2010-280586 A, JP 2010-254543 A, JP 2007-182410 A, WO 2010/010613 A, etc. can be mentioned.
• the above conventionally known method produces a powder (solid) of the sulfonylimide compound.
• the content of the alkali metal salt (total content when two or more types are used in combination) is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, based on the entire electrolyte composition (total amount of the components constituting the electrolyte composition of this embodiment is 100% by mass), from the viewpoint of improving the charge/discharge efficiency and its maintenance rate of the battery, and the upper limit is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less.
• the alkali metal salt contains only a sulfonylimide compound
• the content of the alkali metal salt is interpreted as the content of the sulfonylimide compound.
• the content of the alkali metal salt (sulfonylimide compound) is particularly preferably 10% by mass or more and 80% by mass or less.
• the fluorine-based polymer contains vinylidene fluoride as a constituent unit, and is composed of, for example, polyvinylidene fluoride (PVDF), PVDF-hexafluoropropylene (HFP), PVDF-trifluoroethylene (vinylidene fluoride-trifluoroethylene copolymer), PVDF-ter-trifluoroethylene-ter-chlorotrifluoroethylene (vinylidene fluoride-ter-trifluoroethylene-ter-chlorotrifluoroethylene copolymer), PVDF-ter-trifluoroethylene-ter-1,1-chlorofluoroethylene (vinylidene fluoride-ter-trifluoroethylene-ter-1,1-chlorofluoroethylene copolymer), etc.
• PVDF polyvinylidene fluoride
• HFP polyvinylidene fluoride-trifluoroethylene copolymer
• fluorine-based polymer a copolymer such as PVDF-HFP (vinylidene fluoride-hexafluoropropylene copolymer) is preferable.
• PVDF-HFP vinylene fluoride-hexafluoropropylene copolymer
• Each of these fluorine-based polymers may be used alone, or two or more types may be used in combination.
• the fluoropolymer preferably has a weight-average molecular weight of 50,000 to 1,000,000, more preferably 200,000 to 1,000,000, and even more preferably 300,000 to 1,000,000. If the weight-average molecular weight is 50,000 or more, the film-forming properties when forming a film using the composition are further improved. If the weight-average molecular weight is 1,000,000 or less, the film can be further prevented from hardening, resulting in excellent ionic conductivity.
• the weight-average molecular weight can also be evaluated by measuring the melt flow index (10 min) at 230°C under a load of 10 kg in accordance with ASTM D1238 (ISO 1133). The MFI measured under these conditions can be between 0.2 g/10 min and 20 g/10 min, preferably between 0.5 g/10 min and 10 g/10 min.
• the lower limit is preferably 3% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and most preferably 15% by mass or more
• the upper limit is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less.
• the content of the fluoropolymer (total content when two or more types are used in combination) is, from the viewpoint of improving the breaking strength, preferably at least 50% by mass, more preferably at least 60% by mass, and even more preferably at least 70% by mass, and preferably at most 99% by mass, more preferably at most 95% by mass, based on the total amount of the fluoropolymer and the photo- and/or thermosetting monomer.
• the photo- and/or thermosetting monomer is not particularly limited as long as it has a functional group polymerizable by light and/or heat.
• the functional group include a polymerizable unsaturated group, an epoxy group, an isocyanate group, and the like.
• the photo- and/or thermosetting monomer preferably has a hetero element.
• examples of the hetero element include nitrogen, oxygen, sulfur, phosphorus, chlorine, iodine, bromine, and the like, and is preferably oxygen or nitrogen, and more preferably oxygen.
• the photo- and/or thermosetting monomer may have one polymerizable functional group or two or more polymerizable functional groups.
• the photo- and/or thermosetting monomer is preferably a polyfunctional monomer having two or more polymerizable functional groups, from the viewpoint of improving the film strength of the electrolyte cured material as much as possible.
• Examples of monofunctional monomers having one polymerizable functional group include alkyl (meth)acrylates having a substituent such as methyl (meth)acrylate, ethyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate; alkoxy (poly)alkylene glycol (meth)acrylates such as methoxy (poly)ethylene glycol (meth)acrylate, methoxy (poly)propylene glycol (meth)acrylate, and phenoxyethylene glycol (meth)acrylate; carboxyl group-containing monomers such as 2-acryloyloxyethyl succinate, 2-acryloyloxyethyl tetrahydrophthalate, and (meth)acrylic acid; monofunctional epoxy compounds such as butyl glycidyl ether, tert-butyl glycidyl ether, benzyl glycidyl ether,
• polyfunctional monomers having two or more polymerizable functional groups include 1,3-butanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, (poly)ethylene (poly)propylene glycol di(meth)acrylate, dioxane glycol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, ethylene glycol di(meth)acrylate, dimeth ...
• Polyfunctional (meth)acrylates such as hydroxylated glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and pentaerythritol tetra(meth)acrylate, (poly)ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, (poly)propylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycidyl (meth)acrylate, ⁇ -methylglycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, epoxybutene, 3,4-epoxy-1-pentene, 1,2-epoxy-5,9-cyclododecadiene, 3,4-epoxy- 1-vinylcyclohexene, 1,2-epoxy-5-cyclooctene, vinyl glycidyl ether,
• the above-mentioned monofunctional monomers and polyfunctional monomers may be used alone or in combination of two or more types.
• the photo- and/or thermosetting monomer preferably contains a urethane bond as a constituent unit, such as urethane acrylate. This makes it possible to improve the film strength of the electrolyte cured product obtained by curing the electrolyte composition due to hydrogen bonds between the urethane bonds.
• the content of the photo- and/or thermosetting monomer (total content when two or more types are used in combination) is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 30% by mass or less, with respect to the total amount of the fluoropolymer and the photo- and/or thermosetting monomer, from the viewpoint of improving the breaking strength, and the lower limit is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more.
• the content of the photo- and/or thermosetting monomer (total content when two or more types are used in combination) is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, with respect to the entire electrolyte composition (total amount of the components constituting the electrolyte composition of the present invention is 100% by mass), with respect to the total amount of the components constituting the electrolyte composition of the present invention, from the viewpoint of improving the breaking strength, and the lower limit is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, and the upper limit is preferably 99% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less.
• the photo- and/or thermosetting monomer preferably has a molecular weight of 50 to 4000, more preferably 50 to 3800, and even more preferably 50 to 3500.
• the salt dissociating agent is not particularly limited as long as it promotes dissociation of an alkali metal salt into ions, but is preferably a compound having a hetero element.
• examples of compounds having a hetero element include carbonate compounds, nitrile compounds, sulfonyl compounds, carboxylic anhydrides, sulfate compounds, thioether compounds, sulfite compounds, and nitrogen-containing cyclic compounds.
• the salt dissociating agent is preferably a compound having a boiling point of 100°C or higher, more preferably a compound having a boiling point of 150°C or higher, and even more preferably a compound having a boiling point of 200°C or higher.
• each of these salt dissociating agents may be used alone, or two or more types may be used in combination.
• these salt dissociating agents carbonate compounds, nitrile compounds, and sulfonyl compounds are preferred, sulfonyl compounds and nitrile compounds are more preferred, and sulfonyl compounds are even more preferred, from the viewpoint of further promoting dissociation of an alkali metal salt into ions and improving the ionic conductivity and transport number of an alkali metal cation. That is, the salt dissociating agent contains at least one of a sulfonyl compound, a carbonate compound, and a nitrile compound.
• carbonate compounds include cyclic carbonates such as ethylene carbonate (EC), vinylene carbonate (VC), vinyl ethylene carbonate (VEC), methyl vinylene carbonate (MVC), and ethyl vinylene carbonate (EVC); fluorinated cyclic carbonates such as fluoroethylene carbonate and trifluoropropylene carbonate; and chain carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC).
• cyclic carbonates such as ethylene carbonate (EC), vinylene carbonate (VC), vinyl ethylene carbonate (VEC), methyl vinylene carbonate (MVC), and ethyl vinylene carbonate (EVC)
• fluorinated cyclic carbonates such as fluoroethylene carbonate and trifluoropropylene carbonate
• chain carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC).
• Nitrile compounds include mononitrile compounds and dinitrile compounds.
• Mononitrile compounds include propionitrile, butyronitrile, pentanenitrile, hexanenitrile, heptanenitrile, octanenitrile, pelargononitrile, decanenitrile, undecanenitrile, dodecanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, acrylonitrile, methacrylonitrile, crotononitrile, 3-methylcrotononitrile, 2-methyl-2-butenenitrile, 2-pentenenitrile, 2-methyl-2-pentenenitrile, 3-methyl-2-pentenenitrile, and 2-hexenenitrile.
• Dinitrile compounds include malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelonitrile, suberonitrile, azelanitrile, sebaconitrile, undecanedinitrile, dodecanedinitrile, methylmalononitrile, ethylmalononitrile, isopropylmalononitrile, tert-butylmalononitrile, methylsuccinonitrile, 2,2-dimethylsuccinonitrile, 2,3-dimethylsuccinonitrile, succinonitrile, 2,3,3-trimethylsuccinonitrile, 2,2,3,3-tetramethylsuccinonitrile, 2,3-diethyl-2,3-dimethylsuccinonitrile, 2,2-diethyl-3,3-dimethylsuccinonitrile, bicyclohexyl-1,1-dicarbonitrile, bicyclohexyl-2,2-dicarbonit
• dinitrile compounds are preferred, and compounds represented by the following formula (2) are more preferred.
• NC-R 3 -CN (2) R3 represents an alkylene group having 1 to 6 carbon atoms or an arylene group having 6 to 10 carbon atoms.
• R3 in formula (2) is preferably an alkylene group having 1 to 6 carbon atoms.
• alkylene group having 1 to 6 carbon atoms include methylene, ethylene, n-propylene, isopropylene, n-butylene, t-butylene, n-pentylene, isopentylene, and n-hexylene.
• malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelonitrile and suberonitrile are preferred, with malononitrile, succinonitrile, glutaronitrile and adiponitrile being more preferred.
• Sulfonyl compounds include sulfones such as dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, isopropyl methyl sulfone, n-butyl methyl sulfone, and tert-butyl methyl sulfone; sulfolanes such as sulfolane (tetramethylene sulfone), 2-methyl sulfolane, 3-methyl sulfolane, and 2,4-dimethyl sulfolane; sultones such as sultone, 1,3-propane sultone, and 1,4-butane sultone; busulfan, sulfolene, and the like.
• sulfonyl compounds sulfones and sulfolanes are preferred, and among these, dimethyl sulfone and s
• Carboxylic acid anhydrides include succinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, glutaconic anhydride, itaconic anhydride, diglycolic anhydride, cyclohexanedicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride, phenylsuccinic anhydride, etc.
• sulfate ester compounds include methyl methanesulfonate and trimethylene glycol sulfate.
• thioether compound is tetramethylthiuram monosulfide.
• sulfite ester compounds examples include ethylene sulfite.
• nitrogen-containing cyclic compounds examples include 1-methyl-2-pyrrolidinone, 1-methyl-2-piperidone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone, and N-methylsuccinimide. These nitrogen-containing cyclic compounds may be used alone or in combination of two or more types.
• the content of the salt dissociating agent (total content when two or more types are used in combination) is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, even more preferably 5% by mass or more, and even more preferably 10% by mass or more, based on the entire electrolyte composition (total amount of the components constituting the electrolyte composition of the present invention is 100% by mass), from the viewpoint of further promoting dissociation of the alkali metal salt into ions and further improving the ionic conductivity of the composition, and the upper limit is preferably 95% by mass or less, more preferably 80% by mass or less, even more preferably 60% by mass or less, and even more preferably 40% by mass or less.
• the content of the salt dissociating agent is particularly preferably 10% by mass or more and 40% by mass or less, based on the entire electrolyte composition (total amount of the components constituting the electrolyte composition of the present embodiment is 100% by mass).
• the electrolyte composition of this embodiment may also contain components other than the fluoropolymer, the photo- and/or thermosetting monomer, the alkali metal salt, and the salt dissociator (polymerization initiator, solvent, additive, and other components).
• the electrolyte composition of the present embodiment may contain a polymerization initiator.
• Polymerization initiators include photoradical polymerization initiators, thermal radical initiators, anionic polymerization initiators, photoanionic polymerization initiators, and epoxy resin hardeners.
• photoradical polymerization initiators generate polymerization initiating radicals by irradiation with active energy rays
• thermal radical polymerization initiators can generate polymerization initiating radicals by heating.
• photoanionic polymerization initiators can generate polymerization initiating anion species by irradiation with active energy rays and start a polymerization reaction.
• epoxy resin hardeners are used as hardeners when hardening epoxy resins, and can start a ring-opening polymerization reaction of epoxy groups. Note that the anionic polymerization initiator referred to here is a component that starts a polymerization reaction that generates polymerization initiating anion species, and does not fall under the category of photoanionic polymerization initiators.
• the photoradical polymerization initiator is not particularly limited, but examples thereof include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl ketal, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone oligomer, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-[4-(2-hydroxyethoxy)phenyl ]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- ⁇ 4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl ⁇ -2-methyl
• photoradical polymerization initiators may be used alone or in combination of two or more.
• acetophenones, benzophenones, and acylphosphine oxides are preferred, with 1-hydroxycyclohexyl phenyl ketone, benzophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide being particularly preferred.
• Thermal radical polymerization initiators are not particularly limited, but examples include methyl ethyl ketone peroxide, cyclohexanone peroxide, methylcyclohexanone peroxide, methyl acetacetate peroxide, acetyl acetate peroxide, 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-hexylperoxy)-cyclohexane, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclo Hexane, 1,1-bis(t-butylperoxy)-2-methylcyclohexane, 1,1-bis(t-butylperoxy)-cyclohexane, 1,1-bis(t-butylperoxy)cyclododecane, 1,1-bis(t-butylperoxy)butane, 2,2-bis(4,4-di-t-butylperoxycyclohe
• benzoins such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; benzophenone, o-benzoyl methyl benzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N,N-dimethyl-N-[2-(1-oxo- 2-propenyloxy)ethyl]benzenemethanaminium bromide, (4-benzoylbenzyl)trimethylammonium chloride and other benzophenones, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlor
• Anionic polymerization initiators include, but are not limited to, alkali metal compounds having an alkali metal and a carbon anion, such as sodium naphthalene, n-butyllithium, and t-butyllithium; trialkylaluminums, such as trimethylaluminum, triethylaluminum, tripropylaluminum, triisopropylaluminum, tributylaluminum, and triisobutylaluminum; chlorodialkylaluminum, chlorodiethylaluminum, chlorodipropylaluminum, chlorodiisopropylaluminum, chlorodibutylaluminum, chlorodiisobutylaluminum, bispentamethylcyclopentadienyl samarium, and methyl-bispentamethylcyclopentadienyl samarium.
• the photoanionic polymerization initiator is not particularly limited, but examples include alkoxytitanium, p-chlorophenyl-o-nitrobenzyl ether, etc.
• anionic polymerization initiators and photoanionic polymerization initiators may be used alone or in combination of two or more.
• Epoxy resin hardeners are not particularly limited, but examples include chain aliphatic polyamines such as diethylenetriamine, triethylenetetramine, and dipropenediamine, cyclic aliphatic polyamines such as N-aminoethylpiperazine, menthenediamine, and isophoronediamine, aromatic amines such as metaphenylene diamine and diaminodiphenylmethane, tertiary amines such as 1,8-diazabicyclo(5,4,0)-undecene-7, 1,5-diazabicyclo(4,3,0)-nonene-5, and tris(dimethylaminomethyl)phenol, and 1-cyanoethyl-2-ethyl-4-methyl-2-propanediamine.
• chain aliphatic polyamines such as diethylenetriamine, triethylenetetramine, and dipropenediamine
• cyclic aliphatic polyamines such as N-aminoethylpiperazine,
• epoxy resin curing agent examples include imidazoles such as ethyl imidazole and 2-ethyl-4-methyl imidazole, acid anhydrides such as ethylene glycol bistrimellitate, tetrahydrophthalic anhydride, succinic anhydride, methylcyclohexene dicarboxylic anhydride, chlorendic anhydride, polyazelaic anhydride, and 4-methylhexahydrophthalic anhydride, photocationic polymerization initiators such as diphenyliodonium hexafluorophosphate and triphenylsulfonium hexafluorophosphate, dicyandiamide, triphenylphosphine, and tetraphenylphosphonium tetraphenylborate. These epoxy resin curing agents may be used alone or in combination of two or more.
• the content of the polymerization initiator (total content when two or more types are used in combination) relative to the amount of monomer, from the viewpoint of film-forming properties, is preferably at least 0.1% by mass, more preferably at least 0.2% by mass, and even more preferably at least 0.5% by mass, and is preferably at most 20% by mass, more preferably at most 15% by mass, and even more preferably at most 10% by mass.
• the electrolyte composition of the present embodiment may contain a solvent as necessary.
• the solvent preferably has a boiling point lower than that of the salt dissociating agent.
• the solvent is not particularly limited as long as it has a boiling point lower than that of the salt dissociator, but it is preferable that the solvent dissolves the composition uniformly.
• solvents include, preferably, acetonitrile, dimethyl carbonate, ethyl methyl carbonate, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, methyl ethyl ketone, tetrahydrofuran, acetone, ethanol, ethyl acetate, water, etc. These solvents may be used in combination.
• the amount of solvent used is not particularly limited and may be appropriately determined depending on the production method and materials used.
• the boiling point difference between the solvent and the salt dissociating agent is preferably 50°C or more, more preferably 80°C or more, and most preferably 100°C or more. If the boiling point difference is within the above preferred range, the salt dissociating agent can be sufficiently prevented from decreasing when the solvent is dried, and the effect of the present invention can be more fully exerted.
• the boiling point of the solvent is preferably 150°C or less, and more preferably 120°C or less.
• the electrolyte composition of this embodiment may contain additives for improving various characteristics of secondary batteries, such as non-fluorinated polymers such as polyether polymers, (meth)acrylic polymers, nitrile polymers, and diene polymers, emulsifiers such as anionic emulsifiers, nonionic emulsifiers, and cationic emulsifiers, thickeners such as styrene-maleic acid copolymers and alkali-soluble (meth)acrylic acid-(meth)acrylic acid ester copolymers, preservatives, and dispersants.
• the content of additives in the non-volatile content of the electrolyte composition is preferably 0 to 15% by mass, and more preferably 0 to 10% by mass.
• the electrolyte composition of this embodiment may contain other components as shown below within the scope of not impairing the object of the present invention.
• other components include saturated hydrocarbon compounds such as heptane, octane, and cycloheptane, polymerization inhibitors used in the production of polymers, chain transfer agents and unreacted reaction raw materials, by-products formed by decomposition of reaction raw materials, and binders other than modified cellulose.
• binders examples include synthetic rubbers such as styrene-butadiene rubber and nitrile butadiene rubber, polyamide-based resins such as polyamideimide, polyolefin-based resins such as polyethylene and polypropylene, poly(meth)acrylic resins, polyacrylic acid, and cellulose-based resins such as carboxymethylcellulose (excluding modified cellulose).
• the other components may be used alone or in combination of two or more types.
• the content of the other components is preferably 15% by mass or less, more preferably 12% by mass or less, and even more preferably 10% by mass or less, with respect to the entire electrolyte composition (total amount of the components constituting the electrolyte composition of the present invention is 100% by mass), with the lower limit being 0% by mass or more, particularly from the viewpoint of not inhibiting the conductivity of lithium ions.
• the electrolyte composition of this embodiment is composed of components such as a fluoropolymer, a photo- and/or thermosetting monomer, an alkali metal salt, a salt dissociator, and other components as necessary, and can be prepared, for example, by mixing these components in a predetermined content.
• the electrolyte composition can be suitably used as various battery materials (electrode composition, electrolyte composition) such as electrodes and electrolyte membranes.
• the electrolyte cured product obtained by curing the electrolyte composition of the present embodiment preferably has a lithium ion conductivity of 2.1 ⁇ 10 ⁇ 4 (S/cm) or more, more preferably 2.5 ⁇ 10 ⁇ 4 (S/cm) or more, and even more preferably 3.0 ⁇ 10 ⁇ 4 (S/cm) or more.
• the electrolyte cured product obtained by curing the electrolyte composition of the present embodiment preferably has an ionic conductivity of 3.0 ⁇ 10 (S/cm) or more, more preferably 4.0 ⁇ 10 (S/cm) or more, and even more preferably 5.0 ⁇ 10 (S/cm) or more.
• the cured electrolyte obtained by curing the electrolyte composition of this embodiment preferably has a lithium transport number of 0.24 or more. More preferably, it is 0.4 or more, and even more preferably, it is 0.5 or more.
• the hardened electrolyte obtained by hardening the electrolyte composition of this embodiment is suitable for use as a solid electrolyte.
• the thickness of the hardened electrolyte is preferably 5 ⁇ m to 300 ⁇ m. More preferably, it is 10 ⁇ m to 250 ⁇ m, and even more preferably, it is 15 ⁇ m to 200 ⁇ m.
• the above-mentioned electrolyte cured product may contain a solvent, but it is preferable that the solvent is removed by drying before or after the formation of the cured product.
• the upper limit of the solvent content in the above-mentioned electrolyte cured product is preferably 18% by weight or less, more preferably 5% by weight or less, even more preferably 3% by weight or less, and particularly preferably 1% by weight or less, with the lower limit being 0% by weight or more.
• a solvent may be used when curing the electrolyte composition of this embodiment to obtain the electrolyte cured product, but it is also preferable from the viewpoints of safety and the environment to obtain the electrolyte cured product without using a solvent.
• the electrolyte composition of this embodiment has excellent film-forming properties, making it possible to form an electrolyte membrane without using a support (separator), i.e., a free-standing membrane can be formed.
• the electrolyte cured product of this embodiment is preferably a free-standing membrane that does not include a support, but may also include a support.
• the support is not particularly limited, but examples include woven fabric, nonwoven fabric, (micro)porous membrane, and glass molded body.
• Examples of the above-mentioned woven and nonwoven fabrics include polyolefin resins such as polypropylene, polyethylene, and polymethylpentene, polyester resins such as polyethylene terephthalate (PET), polyamide resins such as nylon, aramid resins such as polyparaphenylene terephthalamide, acrylic resins, polyvinyl alcohol resins, cellulose resins (cellulose fibers), alumina fibers, ceramic fibers, glass fibers, etc.
• Examples of the (micro)porous membrane include polyolefin resins such as polypropylene, polyethylene, and ethylene-propylene copolymers, polyester resins, fluororesins such as tetrafluoroethylene-perfluoroalkoxyethylene copolymers, polyether ether ketone, polybutylene terephthalate, polyphenylene sulfide, polyamide resins, and polyimides.
• Examples of the glass molded body include glass cloth.
• hydrophilic treatments may be used, such as adding a surfactant, sulfonating with chemicals such as fuming sulfuric acid or chlorosulfonic acid, fluorinating, or grafting, or using corona discharge or plasma discharge.
• the separator is preferably made of at least one material selected from the group consisting of cellulose nonwoven fabric, PET nonwoven fabric, glass nonwoven fabric, polyolefin nonwoven fabric, polyolefin microporous membrane, and polyimide porous membrane. Cellulose nonwoven fabric and polyolefin microporous membrane are more preferred.
• the electrolyte cured product of this embodiment is obtained by curing the electrolyte composition of this embodiment.
• methods for producing the electrolyte cured product of the present invention include a method of mixing the electrolyte composition, forming the resulting mixture into a sheet, and then curing it; a method of applying the electrolyte composition by a doctor blade method or the like, or immersing a support in the electrolyte composition, and then drying and curing as necessary; a method of kneading and molding the electrolyte composition into a sheet, and then bonding the sheet to a support via a conductive adhesive, pressing, and curing it; a method of applying or casting a composition to which a liquid lubricant has been added onto a current collector, forming it into a desired shape, removing the liquid lubricant, and then stretching it in a uniaxial or multiaxial direction, and the like.
• the electrolyte composition of the present embodiment can be suitably used as a material for an electrode for a battery.
• An electrode formed using the electrolyte composition of the present embodiment also constitutes the present invention.
• the electrolyte composition of the present invention may be used for either a positive electrode or a negative electrode.
• the electrolyte cured product of this embodiment can be suitably used as an electrode for a battery.
• the electrode of this embodiment is preferably obtained by curing a composition containing the electrolyte composition of this embodiment.
• the electrolyte cured product of this embodiment may be used for either a positive electrode or a negative electrode.
• the positive electrode is a positive electrode active material composition that contains the electrolyte composition of this embodiment, other electrolytes, a positive electrode active material, a conductive assistant, a binder, a dispersion solvent, etc., supported on a positive electrode current collector, and is usually formed into a sheet.
• the other electrolytes known polymer solid electrolytes, inorganic solid electrolytes, molten salts, etc. can be used in combination.
• Examples of methods for manufacturing positive electrodes include a method of mixing a positive electrode active material composition, forming the mixture into a sheet, and then curing the mixture; a method of applying the positive electrode active material composition to a positive electrode current collector using a doctor blade method or the like, or immersing the positive electrode current collector in the positive electrode active material composition, and then drying as necessary; a method of kneading and forming a sheet of the positive electrode active material composition, drying as necessary, bonding the sheet to the positive electrode current collector via a conductive adhesive, pressing, and drying; a method of applying or casting a positive electrode active material composition to which a liquid lubricant has been added, onto a positive electrode current collector, forming the sheet into the desired shape, removing the liquid lubricant, and then stretching the sheet in uniaxial or multiaxial directions.
• the material for the positive electrode current collector is not particularly limited, and may be, for example, a conductive metal such as aluminum, an aluminum alloy, SUS (stainless steel), or titanium.
• a conductive metal such as aluminum, an aluminum alloy, SUS (stainless steel), or titanium.
• aluminum is preferred from the viewpoints that it is easy to process into a thin film and is inexpensive.
• the positive electrode active material may be any positive electrode active material that can absorb and release ions, and may be any of the conventionally known positive electrode active materials.
• the positive electrode active material include a solid solution of 3 with an electrochemically active layered MM′′O (wherein M′′ is a transition metal such as Co or Ni) (M represents an alkali metal ion).
• Conductive additives include acetylene black, carbon black, graphite, metal powder materials, single-walled carbon nanotubes, multi-walled carbon nanotubes, vapor-grown carbon fibers, etc.
• Binders include synthetic rubbers such as styrene-butadiene rubber and nitrile butadiene rubber, polyamide-based resins such as polyamideimide, polyolefin-based resins such as polyethylene and polypropylene, and cellulose-based resins such as poly(meth)acrylic resins, polyacrylic acid, and carboxymethyl cellulose. These binders may be used alone or in combination. These binders may be dissolved in a solvent or dispersed in a solvent when used.
• the amounts of conductive additive and binder can be adjusted appropriately taking into consideration the intended use of the battery (emphasis on output, emphasis on energy, etc.), ionic conductivity, etc.
• examples of the solvent used in the positive electrode active material composition include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, methyl ethyl ketone, tetrahydrofuran, acetonitrile, acetone, ethanol, ethyl acetate, water, etc. These solvents may be used in combination. There are no particular limitations on the amount of solvent used, and it may be determined appropriately depending on the manufacturing method and materials used.
• the negative electrode active material may be any known negative electrode active material used in batteries, as long as it is capable of absorbing and releasing ions. Specifically, it may be possible to use alkali metals, metal alloys such as alkali metal-aluminum alloys, graphite materials such as artificial graphite and natural graphite, mesophase sintered bodies made from coal and petroleum pitch, carbon materials such as non-graphitizable carbon, Si-based negative electrode materials such as Si, Si alloys, and SiO, and Sn-based negative electrode materials such as Sn alloys.
• alkali metals metal alloys such as alkali metal-aluminum alloys
• graphite materials such as artificial graphite and natural graphite
• mesophase sintered bodies made from coal and petroleum pitch carbon materials such as non-graphitizable carbon
• Si-based negative electrode materials such as Si, Si alloys, and SiO
• Sn-based negative electrode materials such as Sn alloys.
• the negative electrode can be manufactured in the same manner as the positive electrode.
• the conductive additive, binder, and material dispersion solvent used in manufacturing the negative electrode are also the same as those used in the positive electrode.
• the secondary battery of the present embodiment is constructed using the electrolyte cured material of the present embodiment and/or the electrode of the present embodiment.
• the secondary battery of this embodiment preferably includes the above-described hardened electrolyte material of this embodiment and/or the above-described electrode of this embodiment.
• the secondary battery of this embodiment is a secondary battery including a positive electrode and a negative electrode, and preferably includes a hardened electrolyte material between the positive electrode and the negative electrode, and is housed in an exterior case together with the positive electrode, the negative electrode, etc.
• the shape of the secondary battery of this embodiment is not particularly limited, and any of the conventionally known shapes of batteries can be used, such as cylindrical, square, laminated, coin, large, etc. Furthermore, when the secondary battery of this embodiment is used as a high-voltage power source (several tens of volts to several hundreds of volts) for installation in electric vehicles, hybrid electric vehicles, etc., it can also be made into a battery module consisting of individual batteries connected in series.
• the electrolyte cured product or electrode containing the electrolyte composition of the present embodiment is used as an electrolyte cured product or electrode for a secondary battery.
• a preferred embodiment of the present invention is one in which the secondary battery is a lithium ion secondary battery.
• Example The present disclosure will be described below based on examples. Note that the present disclosure is not limited to the following examples, and the following examples can be modified or changed based on the spirit of the present disclosure, and are not excluded from the scope of the present disclosure.
• An electrolyte composition was prepared by weighing 1.0 g of acetone (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 3.0 g of acetone (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) into a PP (polypropylene) container (100 mL) and mixing at 2000 rpm for 3 minutes.
• the prepared electrolyte solution was applied onto a Teflon (registered trademark) sheet, the acetone solvent was removed by vacuum drying, and then the solution was irradiated with UV (ultraviolet) light for 12 minutes using an ultra-high pressure mercury lamp (4.2 mW/ cm2 (365 nm) after transmission through the Teflon (registered trademark) sheet) to carry out a photopolymerization reaction, thereby producing a cured electrolyte with a film thickness of 200 ⁇ m.
• UV ultraviolet
• Example 2 As shown in Table 1, the same procedure as in Example 1 was repeated except that the amount of LiFSI was changed from 23 parts by mass to 10 parts by mass and the amount of sulfolane was changed from 52 parts by mass to 65 parts by mass, to prepare a cured electrolyte material having a thickness of 200 ⁇ m.
• Example 3 As shown in Table 1, the amount of LiFSI was changed from 23 parts by mass to 10 parts by mass, the amount of PVDF-HFP was changed from 20 parts by mass to 17.5 parts by mass, the amount of trifunctional urethane acrylate was changed from 5 parts by mass to 7.5 parts by mass, the amount of sulfolane was changed from 52 parts by mass to 65 parts by mass, and the amount of polymerization initiator was changed from 0.5 parts by mass to 0.75 parts by mass. Except for this, a cured electrolyte material having a thickness of 200 ⁇ m was produced in the same manner as in Example 1.
• Example 4 As shown in Table 1, the amount of LiFSI was changed from 23 parts by mass to 12 parts by mass, the amount of PVDF-HFP was changed from 20 parts by mass to 28 parts by mass, the amount of trifunctional urethane acrylate was changed from 5 parts by mass to 7 parts by mass, the amount of sulfolane was changed from 52 parts by mass to 53 parts by mass, and the amount of polymerization initiator was changed from 0.5 parts by mass to 0.7 parts by mass. Except for this, a cured electrolyte material having a thickness of 200 ⁇ m was produced in the same manner as in Example 1.
• Example 5 As shown in Table 1, the amount of LiFSI was changed from 23 parts by mass to 12 parts by mass, the amount of PVDF-HFP was changed from 20 parts by mass to 24.5 parts by mass, the amount of trifunctional urethane acrylate was changed from 5 parts by mass to 10.5 parts by mass, the amount of sulfolane was changed from 52 parts by mass to 53 parts by mass, and the amount of polymerization initiator was changed from 0.5 parts by mass to 1.05 parts by mass. Except for this, a cured electrolyte material having a thickness of 200 ⁇ m was produced in the same manner as in Example 1.
• Example 6 As shown in Table 1, the amount of LiFSI was changed from 23 parts by mass to 26 parts by mass, the amount of PVDF-HFP was changed from 20 parts by mass to 12 parts by mass, the amount of trifunctional urethane acrylate was changed from 5 parts by mass to 3 parts by mass, the amount of sulfolane was changed from 52 parts by mass to 59 parts by mass, and the amount of polymerization initiator was changed from 0.5 parts by mass to 0.3 parts by mass. Except for this, a cured electrolyte material having a thickness of 200 ⁇ m was produced in the same manner as in Example 1.
• Example 7 As shown in Table 1, the amount of LiFSI was changed from 23 parts by mass to 26 parts by mass, the amount of PVDF-HFP was changed from 20 parts by mass to 10.5 parts by mass, the amount of trifunctional urethane acrylate was changed from 5 parts by mass to 4.5 parts by mass, the amount of sulfolane was changed from 52 parts by mass to 59 parts by mass, and the amount of polymerization initiator was changed from 0.5 parts by mass to 0.45 parts by mass. Except for this, a cured electrolyte material having a thickness of 200 ⁇ m was produced in the same manner as in Example 1.
• Example 8 As shown in Table 1, the amount of PVDF-HFP was changed from 20 parts by mass to 23.75 parts by mass, the amount of trifunctional urethane acrylate was changed from 5 parts by mass to 1.25 parts by mass, and the amount of polymerization initiator was changed from 0.5 parts by mass to 0.125 parts by mass. Except for this, the procedure of Example 1 was repeated to prepare a cured electrolyte material having a thickness of 200 ⁇ m.
• Example 9 As shown in Table 1, the amount of PVDF-HFP was changed from 20 parts by mass to 17.5 parts by mass, the amount of trifunctional urethane acrylate was changed from 5 parts by mass to 7.5 parts by mass, and the amount of polymerization initiator was changed from 0.5 parts by mass to 0.75 parts by mass. Except for this, the same procedure as in Example 1 was carried out to prepare a cured electrolyte material having a thickness of 200 ⁇ m.
• Example 10 As shown in Table 1, the amount of LiFSI was changed from 23 parts by mass to 26 parts by mass, the amount of PVDF-HFP was changed from 20 parts by mass to 28 parts by mass, the amount of trifunctional urethane acrylate was changed from 5 parts by mass to 7 parts by mass, the amount of sulfolane was changed from 52 parts by mass to 39 parts by mass, and the amount of polymerization initiator was changed from 0.5 parts by mass to 0.7 parts by mass. Except for this, a cured electrolyte material having a thickness of 200 ⁇ m was produced in the same manner as in Example 1.
• Example 11 As shown in Table 1, the amount of LiFSI was changed from 23 parts by mass to 26 parts by mass, the amount of PVDF-HFP was changed from 20 parts by mass to 24.5 parts by mass, the amount of trifunctional urethane acrylate was changed from 5 parts by mass to 10.5 parts by mass, the amount of sulfolane was changed from 52 parts by mass to 39 parts by mass, and the amount of polymerization initiator was changed from 0.5 parts by mass to 1.05 parts by mass. Except for this, a cured electrolyte material having a thickness of 200 ⁇ m was produced in the same manner as in Example 1.
• Example 12 As shown in Table 1, the same procedure as in Example 1 was repeated except that the amount of LiFSI was changed from 23 parts by mass to 32 parts by mass and the amount of sulfolane was changed from 52 parts by mass to 43 parts by mass, to prepare a cured electrolyte material having a thickness of 200 ⁇ m.
• Example 13 As shown in Table 1, the amount of LiFSI was changed from 23 parts by mass to 26 parts by mass, the amount of PVDF-HFP was changed from 20 parts by mass to 17.5 parts by mass, the amount of trifunctional urethane acrylate was changed from 5 parts by mass to 7.5 parts by mass, the amount of sulfolane was changed from 52 parts by mass to 43 parts by mass, and the amount of polymerization initiator was changed from 0.5 parts by mass to 0.75 parts by mass. Except for this, a cured electrolyte material having a thickness of 200 ⁇ m was produced in the same manner as in Example 1.
• Example 14 As shown in Table 1, the amount of LiFSI was changed from 23 parts by mass to 35 parts by mass, the amount of PVDF-HFP was changed from 20 parts by mass to 28 parts by mass, the amount of trifunctional urethane acrylate was changed from 5 parts by mass to 7 parts by mass, the amount of sulfolane was changed from 52 parts by mass to 30 parts by mass, and the amount of polymerization initiator was changed from 0.5 parts by mass to 0.7 parts by mass. Except for this, a cured electrolyte material having a thickness of 200 ⁇ m was produced in the same manner as in Example 1.
• Example 15 As shown in Table 1, the amount of LiFSI was changed from 23 parts by mass to 35 parts by mass, the amount of PVDF-HFP was changed from 20 parts by mass to 24.5 parts by mass, the amount of trifunctional urethane acrylate was changed from 5 parts by mass to 10.5 parts by mass, the amount of sulfolane was changed from 52 parts by mass to 30 parts by mass, and the amount of polymerization initiator was changed from 0.5 parts by mass to 1.05 parts by mass. Except for this, a cured electrolyte material having a thickness of 200 ⁇ m was produced in the same manner as in Example 1.
• Example 16 As shown in Table 2, a cured electrolyte having a thickness of 200 ⁇ m was prepared in the same manner as in Example 1, except that the amount of LiFSI was changed from 23 parts by mass to 25 parts by mass, and 50 parts by mass of EC/EMC was used instead of 52 parts by mass of sulfolane.
• EC/EMC is a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 3:7.
• Example 17 As shown in Table 2, the amount of LiFSI was changed from 23 parts by mass to 22 parts by mass, and 53 parts by mass of EC was used instead of 52 parts by mass of sulfolane. Except for this, the procedure of Example 1 was repeated to prepare a cured electrolyte material having a thickness of 200 ⁇ m.
• Example 18 As shown in Table 2, the amount of LiFSI was changed from 23 parts by mass to 34 parts by mass, and 41 parts by mass of SN (succinonitrile) was used instead of 52 parts by mass of sulfolane. Except for this, the procedure of Example 1 was repeated to prepare a cured electrolyte having a thickness of 200 ⁇ m.
• Example 19 As shown in Table 2, a cured electrolyte material having a thickness of 200 ⁇ m was produced in the same manner as in Example 1, except that 20 parts by mass of PVDF-HFP was changed from KYNER FLEX 2801-00 to KYNER FLEX 2501-00 (manufactured by ARKEMA Corporation).
• Example 20 As shown in Table 2, a cured electrolyte material having a thickness of 200 ⁇ m was prepared in the same manner as in Example 1, except that 30 parts by mass of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was used instead of 23 parts by mass of LiFSI, and the amount of sulfolane was changed from 52 parts by mass to 45 parts by mass.
• LiTFSI lithium bis(trifluoromethanesulfonyl)imide
• Example 21 As shown in Table 2, a cured electrolyte material having a thickness of 200 ⁇ m was prepared in the same manner as in Example 1, except that 5 parts by mass of the trifunctional urethane acrylate was replaced with a bifunctional PEO (polyethylene oxide)-terminated acrylate (409073 manufactured by ALDRICH Corporation).
• a bifunctional PEO (polyethylene oxide)-terminated acrylate 409073 manufactured by ALDRICH Corporation.
• Example 22 As shown in Table 2, a cured electrolyte material having a thickness of 200 ⁇ m was prepared in the same manner as in Example 1, except that 5 parts by mass of the trifunctional urethane acrylate was replaced with a trifunctional PEO-terminated acrylate (455008 manufactured by ALDRICH).
• VSP-300 potentiogalvanostat
• impedance analysis of the symmetrical cell was performed under conditions of 1 MHz to 10 mHz and an amplitude of 10 mV.
• the bulk resistance component obtained from the Cole-Cole plot was designated Rb, and the interface resistance component between the lithium foil and the hardened electrolyte was designated RSi ( ⁇ ).
• Ii (A) and Ic (A) the current value immediately after the voltage application and the current value 5 minutes later were designated Ii (A) and Ic (A), respectively.
• impedance analysis was carried out under conditions of 1 MHz to 10 mHz and an amplitude of 10 mV, and the interface resistance component between the lithium foil and the cured electrolyte material obtained from the Cole-Cole plot was designated RSc ( ⁇ ).
• the thickness of the measurement specimen was designated T (cm)
• the area of the contact area of the cured electrolyte material with the lithium foil was designated A (cm 2 )
• the lithium transport number was calculated based on the following formula ( ⁇ ) when the applied voltage was E (V).
• tLi Ic(E-RSiIi)/Ii(E-RScIc) ( ⁇ )
• the lithium ion conductivity ⁇ Li was calculated based on the following formula ( ⁇ ) using the above ionic conductivity and lithium transport number.
• ⁇ Li ⁇ tLi ( ⁇ )
• Examples 1 to 15 which contain both a fluoropolymer and a curable monomer and in which the total amount of the fluoropolymer and the curable monomer is 10% by mass or more relative to the total amount of the fluoropolymer, the curable monomer, the lithium salt, and the salt dissociator, the number of cycles in the current test exceeded 110, and it was found that the dendrite resistance performance was improved.
• Comparative Examples 1 and 2 which contain only one of a fluoropolymer and a curable monomer, even if the total amount of the fluoropolymer and the monomer is 25% by mass relative to the total amount of the fluoropolymer, the curable monomer, the lithium salt, and the salt dissociator, the number of cycles in the current test was less than 110, and it was found that the desired dendrite resistance performance was not obtained.
• Example 19 where the type of fluoropolymer was changed, the number of cycles in the current test exceeded 220, indicating that dendrite resistance was improved.
• Example 20 where the type of lithium salt was changed, the number of cycles in the current test exceeded 230, indicating that dendrite resistance was improved.
• the electrolyte composition of this embodiment contains a fluoropolymer and a monomer having photo- and/or thermosetting properties, and the total amount of the fluoropolymer and the curable monomer is 10 mass% or more based on the total amount of the fluoropolymer, the curable monomer, the alkali metal salt, and the salt dissociator. Therefore, in the electrolyte cured product obtained by curing the electrolyte composition, a double network structure is formed in which the cured product of the monomer having photo- and/or thermosetting properties and the fluoropolymer are entangled.
• the electrolyte cured product becomes harder than when the fluoropolymer is not added, and the film strength of the electrolyte cured product can be improved as much as possible while maintaining high lithium ion conductivity. Furthermore, since the film strength of the electrolyte cured product obtained by curing the electrolyte composition is improved, the growth of dendrites of alkali metals such as lithium in the electrolyte cured product is suppressed, and short circuits due to the growth of the dendrites can be suppressed.
• the present invention is useful for electrolytes used in secondary batteries.

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