Electrolyte composition, electrolyte, and battery

Abstract

To provide an electrolyte composition with excellent ion conductivity, an electrolyte, and a battery including the same.SOLUTION: An electrolyte composition includes an ion-conductive inorganic solid electrolyte, a polymer with capability of conducting metal ions with priority, and an ion liquid.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an electrolyte composition, an electrolyte, and a battery. [Background technology]

[0002] Batteries that charge and discharge by the movement of metal ions between the positive and negative electrodes, such as lithium-ion batteries, are being actively researched due to their high capacity. While solutions of lithium salts containing organic solvents or ionic liquids are known as electrolytes for lithium-ion batteries, research on solid electrolytes is progressing from the perspective of safety and processability (Patent Documents 1 and 2, and Non-Patent Document 1). Various types of compounds are known as solid electrolytes, including oxide-based solid electrolytes and sulfide-based solid electrolytes. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Chinese Patent Application No. 112448100 [Patent Document 2] Chinese Patent Application No. 110247111 [Patent Document 3] Korean Published Patent No. 2018-0051079 [Non-patent literature]

[0004] [Non-Patent Document 1] Journal of The Electrochemical Society, 2020, 167, 070559. [Overview of the project] [Problems that the invention aims to solve]

[0005] While solid electrolytes offer excellent ionic conductivity and safety, their rigidity makes them difficult to process, and they also have high interfacial resistance. Therefore, studies have been conducted to impart flexibility to solid electrolytes by compounding them with flexible polymer materials, as described in, for example, Patent Documents 1 and 2, and Non-Patent Document 1. However, our inventors have found that compounding with existing polymer materials results in the composite material not achieving a sufficient level of ionic conductivity.

[0006] The present invention has been made in view of the above-mentioned problems, and aims to provide an electrolyte composition with excellent ionic conductivity, an electrolyte, and a battery equipped therewith. [Means for solving the problem]

[0007] The present invention includes the following exemplary embodiments [1] to [9]. [1] An electrolyte composition comprising an ion-conducting inorganic solid electrolyte, a polymer having the ability to preferentially conduct metal ions, and an ionic liquid. [2] The electrolyte composition of [1], wherein the ion-conducting inorganic solid electrolyte is an oxide, sulfide, hydride, or halide containing at least one of an alkali metal element and an alkaline earth metal. [3] The electrolyte composition of [2], wherein the ion-conducting inorganic solid electrolyte is a perovskite-type oxide, a NASICON-type oxide, a LISICON-type oxide, or a garnet-type oxide. [4] Any one of the electrolyte compositions of [1] to [3], wherein the polymer has at least one of an anionic functional group that has an alkali metal ion as a countercation and a functional group that has anion-scavenging ability. [5] Ionic conductivity at 25°C is 10 -4 One of the electrolyte compositions [1] to [4], having a concentration of S / cm or higher. [6] Any one of the electrolyte compositions [1] to [5], having an activation energy of 30 kJ / mol or less. [7] The dynamic hardness DH calculated from the following formula using the results of nanoindenter tests at 25°C was 10 3 N / mm 2 The following is the electrolyte composition. DH = α × F / h 2 ×10 3 α = 3.8584 F: Testing ability h: depth of indentation An electrolyte comprising one of the electrolyte compositions [8][1] to [7]. A battery comprising one of the electrolyte compositions [9][1] to [7]. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an electrolyte composition with excellent ionic conductivity, an electrolyte, and a battery equipped therewith. [Modes for carrying out the invention]

[0009] The electrolyte composition of this embodiment comprises an ion-conducting inorganic solid electrolyte, a polymer having the ability to preferentially conduct metal ions, and an ionic liquid.

[0010] [Ionic conductive inorganic solid electrolytes] The ion-conducting inorganic solid electrolyte is not particularly limited and may be an oxide (oxide-based solid electrolyte), sulfide (sulfide-based solid electrolyte), hydride (hydride-based solid electrolyte), or halide (halide-based solid electrolyte), etc. The ion-conducting inorganic solid electrolyte may contain at least one of an alkali metal element and an alkaline earth metal element, and may contain an alkali metal element.

[0011] (Oxide solid electrolyte) Examples of oxide-based solid electrolytes include perovskite-type oxides, NASICON-type oxides, LISICON-type oxides, garnet-type oxides, and oxides doped with other cations or anions.

[0012] As perovskite oxides, there are Li a La 1-a TiO3 (0 < a < 1) and other Li-La-Ti oxides, Li b La 1-b TaO3 (0 < b < 1) and other Li-La-Ta oxides, Li c La 1-c NbO3 (0 < c < 1) and other Li-La-Nb oxides, etc.

[0013] As NASICON oxides, there are Li 1+d Al d Ti 2-d (PO4)3 (0 ≤ d ≤ 1), etc. NASICON oxides are Li m M 1 n M 2 o P p O q (where M 1 is one or more elements selected from the group consisting of B, Al, Ga, In, C, Si, Ge, Sn, Sb, and Se. M 2 is one or more elements selected from the group consisting of Ti, Zr, Ge, In, Ga, Sn, and Al. m, n, o, p, and q are arbitrary positive numbers.) and are oxides represented by Li 1+x+y Al x (Ti, Ge) 2-x Si y P 3-y O 12 (0 < x < 2, 0 < y < 3) (LATP), etc.

[0014] As LISICON oxides, there are Li4M 3 O4 - Li3M 4 O4 (M 3 is one or more elements selected from the group consisting of Si, Ge, and Ti. M 4 is one or more elements selected from the group consisting of P, As, and V.) and oxides represented by such, etc.

[0015] As garnet oxides, there are Li7La3Zr2O 12(LLZ), Li 7-a2 La3Zr 2-a2 Ta a2 O 12 Examples include Li-La-Zr-based oxides such as (LLZT, where 0 < a2 < 1, 0.1 < a2 < 0.8, or 0.2 < a2 < 0.6).

[0016] The oxide-based solid electrolyte may be a crystalline material or an amorphous material.

[0017] Examples of the oxide-based solid electrolyte include Li 6.6 La3Zr 1.6 Ta 0.4 O 12 Li 0.33 La 0.55 TiO3, etc.

[0018] (Sulfide-based solid electrolyte) Examples of the sulfide-based solid electrolyte include Li2S-P2S5-based compounds, Li2S-SiS2-based compounds, Li2S-GeS2-based compounds, Li2S-B2S3-based compounds, Li2S-P2S3-based compounds, LiI-Si2S-P2S5, LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li 10 GeP2S 12 and the like.

[0019] In this specification, the expression "system compound" referring to the sulfide-based solid electrolyte is used as a general term for solid electrolytes mainly containing raw materials such as "Li2S" and "P2S5" described before "system compound". For example, Li2S-P2S5-based compounds include solid electrolytes containing Li2S and P2S5 and further containing other raw materials. Also, Li2S-P2S5-based compounds include solid electrolytes with different mixing ratios of Li2S and P2S5.

[0020] Examples of Li2S-P2S5-based compounds include Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-LiCl, Li2S-P2S5-LiBr, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-P2S5-Zm S n Examples include (where m and n are positive numbers, and Z is Ge, Zn, or Ga).

[0021] Li2S-SiS2 compounds include Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li2SO4, and Li2S-SiS2-Li x MO y Examples include (x and y are positive numbers, and M is P, Si, Ge, B, Al, Ga, or In).

[0022] Examples of Li2S-GeS2-based compounds include Li2S-GeS2 and Li2S-GeS2-P2S5.

[0023] The sulfide-based solid electrolyte may be a crystalline material or an amorphous material.

[0024] (Hydroxide-based solid electrolytes) Examples of hydride-based solid electrolyte materials include LiBH4, LiBH4-3KI, LiBH4-PI2, LiBH4-P2S5, LiBH4-LiNH2, 3LiBH4-LiI, LiNH2, Li2AlH6, Li(NH2)2I, Li2NH, LiGd(BH4)3Cl, Li2(BH4)(NH2), Li3(NH2)I, and Li4(BH4)(NH2)3.

[0025] (Halogenated solid electrolytes) Examples of halide solid electrolytes include compounds containing lithium, a metal element, and a halogen element. The halide solid electrolyte may be a crystalline material or an amorphous material.

[0026] Examples of ion-conducting inorganic solid electrolytes include compounds obtained by replacing some or all of the Li in the compounds listed as specific examples of oxide-based solid electrolytes, sulfide-based solid electrolytes, hydride-based solid electrolytes, or halide-based solid electrolytes with Na, K, Rb, or Cs.

[0027] The content of the ion-conducting inorganic solid electrolyte may be 50% by mass or more, 55% by mass or more, 60% by mass or more, 65% by mass or more, or 70% by mass or more, based on the total amount of the electrolyte composition. Furthermore, the content of the ion-conducting inorganic solid electrolyte may be 95% by mass or less, or 90% by mass or less, based on the total amount of the electrolyte composition. Furthermore, the content of the ion-conducting inorganic solid electrolyte may be 50 to 99% by mass, 55 to 95% by mass or 65 to 90% by mass, based on the total amount of the electrolyte composition.

[0028] The content of the ion-conducting inorganic solid electrolyte may be 15% by volume or more, 25% by volume or more, 35% by volume or more, 40% by volume or more, or 45% by volume or more, relative to the total amount of the electrolyte composition. Furthermore, the content of the ion-conducting inorganic solid electrolyte may be 90% by volume or less, 80% by volume or less, 70% by volume or less, or 60% by volume or less, relative to the total amount of the electrolyte composition. Furthermore, the content of the ion-conducting inorganic solid electrolyte may be 15 to 90% by volume, 20 to 80% by volume, or 30 to 70% by volume, relative to the total amount of the electrolyte composition. In this specification, unless otherwise specified, volume percent is calculated based on the volume of each component in the electrolyte composition before mixing. If the mass ratio of each component in the electrolyte composition is known, the volume percent may be the value obtained by dividing the mass ratio of each component by its density.

[0029] Ion-conducting inorganic solid electrolytes may have their particle surfaces treated. Specifically, this could involve treatments such as removing the surface non-conductive layer with an acid, or forming covalent bonds with atoms. The acid used is not particularly limited, but examples include hydrochloric acid, nitric acid, and phosphoric acid.

[0030] [A polymer that has the ability to preferentially conduct metal ions] A polymer having the ability to preferentially conduct metal ions (hereinafter also simply referred to as "polymer") may, for example, be a composition containing 33% by mass of the polymer and 67% by mass of a nonionic plasticizer at room temperature (25°C), or a composition containing 31.9% by mass of the polymer, a metal salt, and the remaining amount of a nonionic plasticizer, with a metal ion concentration of 0.3 mol / L, where the transport fraction of metal ions is measured to be 0.4 or higher, 0.5 or higher, 0.6 or higher, or 0.7 or higher. The metal ions contained in the composition may be the countercations of anionic functional groups if the polymer has anionic functional groups, or they may be added as metal salts. A polymer having the ability to preferentially conduct metal ions may be a polymer having the ability to preferentially conduct alkali metal ions. Examples of nonionic plasticizers include at least one of organic solvents and other resins such as fluororesins. The organic solvent may be an aprotic solvent. The aprotic solvent may be at least one selected from the group consisting of carbonate solvents, fluorine solvents, and ether solvents. Examples of carbonate solvents include linear carbonates such as dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate; and cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, and vinylene carbonate. Examples of fluorine solvents include hydrofluorocarbons such as perfluorooctane; hydrofluoroethers such as methyl nonafluorobutyl ether and ethyl nonafluorobutyl ether; and hydrofluoroolefins such as 1,3,3,3-tetrafluoropropene. Examples of ether solvents include cyclic ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, and 1,3-dioxolane; and linear ethers such as 1,2-diethoxyethane and ethoxymethoxyethane. As the fluororesin, a resin having a carbon chain as its main chain is preferred. The carbon chain may be formed by radical polymerization of ethylenically unsaturated groups. The concentration of metal ions may be adjusted by adding a metal salt. For example, if the metal salt is an alkali metal salt, the alkali metal salt is not particularly limited, but M can be MF, MCl, MBr, MI, MClO4, MPF6, MBF4, M2SO4, M[(C h F 2h+1 )SO3](h is 0~3), M[(C h F 2h+1 Examples include )SO2]2N (where h is 0-3). If the polymer has structural unit (A), M may be the same alkali metal element as the alkali metal element present in structural unit (A).

[0031] Polymers having the ability to preferentially conduct metal ions include those containing at least one of an anionic functional group (also called functional group (A)) having a metal ion as a countercation, and a functional group (also called functional group (B)) having anion-scavenging ability. There are no particular restrictions on the structure of the polymer, but examples include those having a carbon chain as the main chain, and this carbon chain may be formed by radical addition polymerization of monomers having ethylenically unsaturated groups.

[0032] The metal ion that is the countercation of functional group (A) may be at least one of alkali metal ions and alkaline earth metal ions, and may be an alkali metal ion. Examples of alkali metal ions include lithium ions, sodium ions, potassium ions, rubidium ions, cesium ions, etc., and may be lithium ions, sodium ions, or potassium ions, and may be lithium ions, sodium ions, or lithium ions. Hereinafter, the structural unit containing functional group (A) and the metal ion that is the countercation of functional group (A) will also be called structural unit (A). Structural unit (A) may have a structure obtained by radical addition polymerization of a monomer having an ethylenically unsaturated group. The metal ion that is the countercation of functional group (A) may be the same alkali metal ion as the alkali metal ions contained in ion-conducting inorganic solid electrolytes.

[0033] Structural unit (A) may have at least one functional group (A) selected from the group consisting of a conjugated anion of a sulfonylimide group, a conjugated anion of a sulfonic acid group, and a conjugated anion of a phenolic hydroxyl group. The conjugated anions of the sulfonylimide group, the sulfonic acid group, and the phenolic hydroxyl group may be, for example, groups having a conjugated anion of a sulfonylimide group, a group having a conjugated anion of a sulfonic acid group (sulfonate group), and a group having a conjugated anion of a phenolic hydroxyl group, as described below.

[0034] The group having a sulfonylimide group may be the group represented by the following formula (A1). [ka] (In formula (A1), X is a divalent organic group having 1 to 20 carbon atoms, Y is a halogen atom, or a monovalent organic group having 1 to 20 carbon atoms, M + (This represents an alkali metal ion, and * indicates the position where structural unit (A1) bonds with other structural units.)

[0035] X is not particularly limited and may be a hydrocarbon group, a group having a heteroatom, or a heterocycle. More specifically, X may be a hydrocarbon group, or a divalent group having a chemical structure in which one or more carbon atoms (methylene group) in the hydrocarbon group are substituted by linking groups of -O-, -S-, -C(=O)-, or -C(=O)O-. If there are multiple linking groups, they are not adjacent to each other. Furthermore, the above divalent group may have substituents that substitute for hydrogen atoms bonded to carbon atoms. The substituents may be monovalent substituents, such as halogen atoms. The above hydrocarbon group is not particularly limited and may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be a linear hydrocarbon group, a branched hydrocarbon group, or a cyclic hydrocarbon group. Furthermore, the hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. X may be bonded to one or both of the nitrogen atom of the maleimide group and the sulfur atom of the sulfonyl group by the carbon atoms of X.

[0036] The number of carbon atoms in X may be 1 to 15, 2 to 10, or 3 to 8. X may be a group having an aromatic ring, or a group having an aromatic carbon ring such as a benzene ring. Substituents such as alkyl groups, halogen atoms, or electron-withdrawing groups may be bonded to the carbon atoms that are members of the carbon ring. The hydrocarbon group as X is preferably a phenylene group, an alkylene group having 1 to 8 carbon atoms, a polyoxyalkylene group, or a group in which some or all of the hydrogen atoms bonded to the carbon atoms thereon are substituted with halogen atoms such as fluorine atoms, and more preferably a phenylene group or a substituted phenylene group substituted with an alkyl group, halogen atom, or electron-withdrawing group. Examples of electron-withdrawing groups include halogen atoms, sulfonic acid groups or their salts, sulfonic acid esters, nitro groups, and nitrile groups.

[0037] In formula (A1), if Y is a monovalent organic group, there are no particular restrictions on the organic group, and it may be a hydrocarbon group, a group having a heteroatom, or a heterocycle. More specifically, Y can be a monovalent group such as a hydrocarbon group or a group having a chemical structure in which one or more carbon atoms (methylene groups) in the hydrocarbon group are substituted by linking groups of -O-, -S-, -C(=O)-, or -C(=O)O-. If there are multiple linking groups, the linking groups are not adjacent to each other. Furthermore, the above monovalent group may have substituents that substitute for hydrogen atoms bonded to carbon atoms. The substituents may be monovalent substituents, such as halogen atoms. The above hydrocarbon group is not particularly limited and may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be a linear hydrocarbon group, a branched hydrocarbon group, or a cyclic hydrocarbon group. Furthermore, the hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group.

[0038] The number of carbon atoms in Y may be 1 to 15, 1 to 10, 1 to 8, 1 to 5, or 1 to 3. The hydrocarbon group as Y is preferably a phenyl group, an alkyl group having 1 to 5 carbon atoms, or a group in which some or all of the hydrogen atoms bonded to the carbon atoms are substituted with halogen atoms such as fluorine atoms. A fluorinated alkyl group having 1 to 5 carbon atoms is more preferred, and a fluorinated alkyl group having 1 to 3 carbon atoms such as a trifluoromethyl group is even more preferred. The fluorinated alkyl group may be a total fluorinated alkyl group. When Y is a halogen atom, the halogen atom is preferably a fluorine atom or a chlorine atom, with a fluorine atom being more preferred.

[0039] In formula (A1), M + It is an alkali metal ion, and lithium ion (Li + ), sodium ions (Na + ), or potassium ions (K + It is preferable that it is lithium ion, and more preferably M + Li+ kaNa + , and K + It may contain two or three types of ions, but it is preferable to contain substantially only a single ion.

[0040] A group having a conjugated anion of a phenolic hydroxyl group is a group in which a hydroxyl group directly bonded to the aromatic ring (i.e., a phenolic hydroxyl group (-OH)) is alkali-metallated (i.e., an -OM group with M being an alkali metal).

[0041] The structural unit (A) may be a group represented by the following formula (A2).

[0042] [ka] (In formula (A2), Y 2 R is a group having an alkali-metallated phenolic hydroxyl group, or a group having a conjugated anion of sulfonic acid, and * indicates the bonding position of structural unit (A2) with other structural units. 15 ~R 17 Each is independently a hydrogen atom or a monovalent substituent, or R 16 R is a hydrogen atom or a monovalent substituent, 15 and R 17 They combine to form a divalent substituent.

[0043] R 15 ~R 17 One or more of them may be hydrogen atoms, or they may all be hydrogen atoms.

[0044] R 15 ~R 17If the substituent is monovalent, the monovalent substituent may be a monovalent organic group. The number of carbon atoms in the organic group may be 1 to 20, 1 to 15, 1 to 10, 1 to 5, or 1 to 3. Examples of organic groups include monovalent substituents such as hydrocarbon groups, groups having a chemical structure formed by substituting one or more carbon atoms (methylene groups) in the hydrocarbon group with -O-, -S-, -C(=O)-, or -C(=O)O- linking groups, and heterocyclic groups. Furthermore, the monovalent substituent may have substituents that substitute for hydrogen atoms bonded to carbon atoms. Examples of substituents include halogen atoms. The hydrocarbon group is not particularly limited and may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be a linear hydrocarbon group, a branched hydrocarbon group, or a cyclic hydrocarbon group. Furthermore, the hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. Examples of hydrocarbon groups include methyl, ethyl, propyl, and phenyl groups.

[0045] R 15 ~R 17 Regarding this, the monovalent substituent may have an electron-withdrawing group, or it may be the electron-withdrawing group itself. The electron-withdrawing group may be bonded to the monovalent organic group, or the monovalent organic group may be the electron-withdrawing group. Examples of electron-withdrawing groups include halogen atoms, sulfonic acid groups or their salts, sulfonic acid esters, nitro groups, nitrile groups, etc. The halogen atom may be any of fluorine, chlorine, bromine, and iodine atoms.

[0046] R 15 and R 17When these groups combine to form a divalent organic group, the number of carbon atoms in the divalent organic group may be 1 to 20, 1 to 15, 1 to 10, 1 to 5, or 1 to 3. Examples of organic groups include hydrocarbon groups, groups having a chemical structure formed by substituting one or more carbon atoms (methylene groups) in the hydrocarbon group with -O-, -S-, -C(=O)-, or -C(=O)O- linking groups, and groups having heterocyclic structures. The above-mentioned divalent organic group may also have substituents that substitute for hydrogen atoms bonded to carbon atoms. Examples of substituents include halogen atoms. The above-mentioned hydrocarbon group is not particularly limited and may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be a linear hydrocarbon group, a branched hydrocarbon group, or a cyclic hydrocarbon group. The hydrocarbon group may also be a saturated hydrocarbon group or an unsaturated hydrocarbon group. Examples of hydrocarbon groups include propylene groups and butylene groups.

[0047] Y 2 If is a group having a phenolic hydroxyl group, Y 2 The base may be represented by any of the following formulas (A21) to (A26). [ka] (In formula (A21), R A At least one of the groups is an -OM group, the rest are hydrogen atoms or monovalent substituents, and M is an alkali metal element, which may be Li, Na or K. In formula (A22), R B At least one of the groups is an -OM group, the rest are hydrogen atoms or monovalent substituents, and M is an alkali metal element, which may be Li, Na or K. In formula (A23), R C At least one of the groups is an -OM group, the rest are hydrogen atoms or monovalent substituents, and M is an alkali metal element, which may be Li, Na or K. In formula (A24), R DAt least one of the groups is an -OM group, the rest are hydrogen atoms or monovalent substituents, and M is an alkali metal element, which may be Li, Na or K. In formula (A25), R E At least one of the groups is an -OM group, the rest are hydrogen atoms or monovalent substituents, and M is an alkali metal element, which may be Li, Na or K. In formula (A26), R F At least one of the groups is an -OM group, the rest are hydrogen atoms or monovalent substituents, and M is an alkali metal element, which may be Li, Na, or K.

[0048] The groups represented by formulas (A21) to (A26) may have 1 to 3 -OM groups, 1 or 2 -OM groups, or 1 -OM group.

[0049] In formulas (A21) to (A26), the monovalent substituent is preferably an electron-withdrawing group. Examples of electron-withdrawing groups include halogen atoms, sulfonic acid groups or their salts, sulfonic acid esters, nitro groups, and nitrile groups. The halogen atom may be any of F, Cl, Br, and I.

[0050] Furthermore, in formulas (A21) to (A26), the monovalent substituent may be an organic group having 1 to 20 carbon atoms. The number of carbon atoms in the organic group may be 1 to 15, 1 to 10, 1 to 5, or 1 to 3. Examples of organic groups include monovalent groups such as hydrocarbon groups, groups having a chemical structure formed by substituting one or more carbon atoms (methylene groups) in the hydrocarbon group with linking groups of -O-, -S-, -C(=O)-, or -C(=O)O-, and groups having heterocyclic structures. The above monovalent group may also have substituents that substitute for hydrogen atoms bonded to carbon atoms. Examples of substituents include halogen atoms. The above hydrocarbon group is not particularly limited and may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be a linear hydrocarbon group, a branched hydrocarbon group, or a cyclic hydrocarbon group. The hydrocarbon group may also be a saturated hydrocarbon group or an unsaturated hydrocarbon group. Examples of hydrocarbon groups include methyl, ethyl, propyl, and phenyl groups. Note that monovalent organic groups may themselves be electron-withdrawing groups.

[0051] Y 2 If is a group having a conjugated anion of sulfonic acid, Y 2 One example is the group represented by the following formula (A3). [ka] (In formula (A3), R 19 (This refers to a covalent or divalent organic group. M is an alkali metal element, which may be Li, Na, or K.)

[0052] In formula (A3), the number of carbon atoms in the divalent organic group may be 1 to 20, 1 to 15, 1 to 10, 1 to 5, or 1 to 3. Examples of organic groups include divalent substituents such as hydrocarbon groups, groups having a chemical structure formed by substituting one or more carbon atoms (methylene groups) in the hydrocarbon group with linking groups of -O-, -S-, -C(=O)-, or -C(=O)O-, and groups having heterocyclic structures. Furthermore, the above-mentioned divalent organic group may have substituents that substitute for hydrogen atoms bonded to carbon atoms. Examples of substituents include halogen atoms. The above-mentioned hydrocarbon group is not particularly limited and may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be a linear hydrocarbon group, a branched hydrocarbon group, or a cyclic hydrocarbon group. Furthermore, the hydrocarbon group may be either a saturated hydrocarbon group or an unsaturated hydrocarbon group. Examples of hydrocarbon groups include methylene groups and phenylene groups.

[0053] Groups having a conjugated anion of sulfonic acid include -SO3M, -CH2-SO3M, and -C6H4-SO3M.

[0054] Functional group (B) is a functional group that functions as an anion receptor. An anion receptor is a chemical species that captures anions by forming electrostatic interactions, hydrogen bonds, acid-base complexes, etc. Functional group (B) captures the counter-anion of a metal ion in a metal salt and promotes the dissociation of the counter-anion and the metal ion. As a result, the mobility of the metal ion increases, and since the counter-anion is captured by the polymer via structural unit (B), the mobility of the counter-anion decreases, and as a result, the transportability of the metal ion is thought to improve. In addition, because the mobility of the metal ion increases, the conductivity of the metal ion also tends to improve.

[0055] Small chemical species (compounds, etc.) that function as anion receptors are known. Examples of such species include the compounds described in U.S. Patent No. 6,022,643, U.S. Patent No. 5,705,689, U.S. Patent No. 6,120,941, etc. The functional group (B) has a structure corresponding to a chemical species that functions as an anion receptor. Since the functional group is fixed to the polymer, unlike conventional low-molecular-weight anion receptors, the trapped anion can be fixed on the polymer structure, and it is considered that the involvement of the anion in the current due to its movement can be more effectively suppressed.

[0056] In addition, the counter anion of the alkali metal salt does not necessarily have to be a free anion that is completely ionized when trapped by the above functional group, and it may interact with the above functional group and be trapped in a state of forming an ionic bond or an ion pair with the metal ion.

[0057] The functional group having a function as an anion receptor may have Lewis acidity. In this case, the functional group can accept the non-bonding electron pair of the anion and trap the anion by forming an acid-base complex. Examples of such functional groups include functional groups having an electron-deficient atom. The electron-deficient atom refers to an atom that is covalently bonded to other atoms but whose outermost shell electrons do not form an octet. Examples of the electron-deficient atom include atoms belonging to Group 13 of the periodic table, and more specifically, it may be at least one of aluminum and boron, and may be boron.

[0058] Also, the functional group having a function as an anion receptor may be a group having an azaether moiety. The group having an azaether moiety is a group having an azaether compound as a substituent, and the azaether compound is obtained by replacing -O- of an ether compound with -NR E -(where R EIt is a compound in which (is a hydrogen atom or an organic group) is replaced. The azoether moiety may be either a chain azoether moiety or a cyclic azoether moiety, and may have both a chain azoether moiety and a cyclic azoether moiety. The group having an azoether moiety may have an electron-withdrawing group, for example, in a hydrocarbon moiety or the like.

[0059] The functional group (B) may be contained, for example, in a structural unit (B) represented by the following formula (B). [Chemical formula] (In the formula (B), W is a functional group having a function as an anion receptor, and R 1 ~R 3 are each independently a hydrogen atom or a monovalent substituent, or R 3 is a hydrogen atom or a monovalent substituent, and R 1 and R 2 together form a divalent organic group. * represents the position where the structural unit (B) is bonded to another structural unit.) The polymer having the ability to preferentially conduct metal ions may contain one or more structural units represented by the formula (B).

[0060] R 1 ~R 3 One or more of them may be a hydrogen atom, or all of them may be hydrogen atoms. W may be a group represented by the following formula (B1).

[0061] R 1 ~R 3If the substituent is monovalent, the monovalent substituent may be a monovalent organic group. The number of carbon atoms in the organic group may be 1 to 20, 1 to 15, 1 to 10, 1 to 5, or 1 to 3. Examples of organic groups include monovalent substituents such as hydrocarbon groups, groups having a chemical structure formed by substituting one or more carbon atoms (methylene groups) in the hydrocarbon group with -O-, -S-, -C(=O)-, or -C(=O)O- linking groups, and heterocyclic groups. Furthermore, the monovalent substituent may have substituents that substitute for hydrogen atoms bonded to carbon atoms. Examples of substituents include halogen atoms. The hydrocarbon group is not particularly limited and may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be a linear hydrocarbon group, a branched hydrocarbon group, or a cyclic hydrocarbon group. Furthermore, the hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. Examples of hydrocarbon groups include methyl, ethyl, propyl, and phenyl groups.

[0062] In this specification, an aromatic hydrocarbon group is a group containing an aromatic moiety and may also have an aliphatic moiety. In this specification, a cyclic hydrocarbon group is a group containing a cyclic hydrocarbon moiety and may also contain a linear or branched hydrocarbon moiety.

[0063] The monovalent substituent may have an electron-withdrawing group, or it may be the electron-withdrawing group itself. The electron-withdrawing group may be bonded to the monovalent organic group, or the monovalent organic group may be the electron-withdrawing group. Examples of electron-withdrawing groups include halogen atoms, sulfonic acid groups or their salts, sulfonic acid esters, nitro groups, and nitrile groups. The halogen atom may be any of fluorine, chlorine, bromine, and iodine atoms.

[0064] R 1 and R 2When these groups combine to form a divalent organic group, the number of carbon atoms in the divalent organic group may be 1 to 20, 1 to 15, 1 to 10, 1 to 5, or 1 to 3. Examples of organic groups include hydrocarbon groups, groups having a chemical structure formed by substituting one or more carbon atoms (methylene groups) in the hydrocarbon group with -O-, -S-, -C(=O)-, or -C(=O)O- linking groups, and groups having heterocyclic structures. The above-mentioned divalent organic group may also have substituents that substitute for hydrogen atoms bonded to carbon atoms. Examples of substituents include halogen atoms. The above-mentioned hydrocarbon group is not particularly limited and may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be a linear hydrocarbon group, a branched hydrocarbon group, or a cyclic hydrocarbon group. The hydrocarbon group may also be a saturated hydrocarbon group or an unsaturated hydrocarbon group. Examples of hydrocarbon groups include propylene groups and butylene groups.

[0065] It is preferable that W has a group represented by the following formula (B1). [ka] (In formula (B1), W B R is an atom belonging to Group 13 of the periodic table. 5 R is a covalent or divalent organic group. 6 and R 7 R is a halogen atom or a monovalent organic group, or together forms a divalent organic group. 6 and R 7 (These may be the same group or different groups.)

[0066] W B This may be at least one of aluminum and boron, and may be boron.

[0067] R 5If is a divalent organic group, the number of carbon atoms in the divalent organic group may be 1 to 20, 1 to 15, 1 to 10, 1 to 5, or 1 to 3. Examples of organic groups include hydrocarbon groups, groups having a chemical structure formed by substituting one or more carbon atoms (methylene groups) in the hydrocarbon group with linking groups of -O-, -S-, -C(=O)-, or -C(=O)O-, and monovalent substituents such as heterocyclic groups. Furthermore, the above divalent organic group may have substituents that substitute for hydrogen atoms bonded to carbon atoms. The substituents may be electron-withdrawing groups. Examples of electron-withdrawing groups include halogen atoms, sulfonic acid groups or their salts, sulfonic acid esters, nitro groups, and nitrile groups. The halogen atom may be any of fluorine, chlorine, bromine, and iodine atoms. 5 This refers to a hydrocarbon group, a halogen-substituted hydrocarbon group, or a hydrocarbon group or halogen-substituted hydrocarbon group connected via an ether bond. B It may be a group that bonds to. The halogen-substituted hydrocarbon group may be one in which some or all of the hydrogen atoms of the hydrocarbon group are replaced with halogen atoms, and may be a partially fluorinated hydrocarbon group or a fully fluorinated hydrocarbon group. 5 The bond may be covalent.

[0068] R 6 or R 7 If the atom is a halogen atom, it may be any of fluorine, chlorine, bromine, or iodine, with fluorine being preferred.

[0069] R 6 or R 7When is a monovalent organic group, the number of carbon atoms in the monovalent organic group may be 1 to 20, 1 to 15, 1 to 10, 1 to 5, or 1 to 3. Examples of organic groups include hydrocarbon groups, groups having a chemical structure formed by substituting one or more carbon atoms (methylene groups) in the hydrocarbon group with -O-, -S-, -C(=O)-, or -C(=O)O- linking groups, and monovalent substituents such as heterocyclic groups. Furthermore, the above monovalent organic group may have substituents that substitute for hydrogen atoms bonded to carbon atoms. The substituents may be electron-withdrawing groups. Examples of electron-withdrawing groups include halogen atoms, sulfonic acid groups or their salts, sulfonic acid esters, nitro groups, and nitrile groups. The halogen atom may be any of fluorine, chlorine, bromine, and iodine atoms. 6 or R 7 This refers to a hydrocarbon group, a halogen-substituted hydrocarbon group, or a hydrocarbon group or halogen-substituted hydrocarbon group connected via an ether bond. B It may be a group that bonds to the hydrocarbon group. The halogen-substituted hydrocarbon group may be one in which some or all of the hydrogen atoms of the hydrocarbon group are replaced with halogen atoms, and may be a partially fluorinated hydrocarbon group or a fully fluorinated hydrocarbon group.

[0070] W may be a group represented by the following formula (B1a) or a group represented by the following formula (B1b). [ka] (In formula (B1a), X 1 and X 2 Each of these is either an oxygen atom (ether bond) or a covalent bond, R 11 and R 12 Each of these is a halogen atom, a monovalent hydrocarbon group, a hydrogen atom, or a monovalent halogen-substituted hydrocarbon group, and may be a halogen atom, a monovalent hydrocarbon group, or a monovalent halogen-substituted hydrocarbon group, R 11 and R 12 At least one of them may be a monovalent hydrocarbon group or a monovalent halogen-substituted hydrocarbon group. 11 and R12 These may be the same group or different groups. [ka] (In formula (B1b), X 3 and X 4 Each of these is either an oxygen atom (ether bond) or a covalent bond, R 13 (This refers to a divalent hydrocarbon group or a divalent halogen-substituted hydrocarbon group.)

[0071] In equation (B1a), R 11 If X is a halogen atom, 1 The bond may be a covalent bond, R 12 If X is a halogen atom, 2 The bond may be covalent. 11 Or R 12 If is a monovalent hydrocarbon group or a monovalent halogen-substituted hydrocarbon group, the number of carbon atoms in the monovalent hydrocarbon group or monovalent halogen-substituted hydrocarbon group may be 1 to 20, 1 to 15, 1 to 10, 1 to 5, or 1 to 3. The halogen-substituted hydrocarbon group may be one in which some or all of the hydrogen atoms in the hydrocarbon group are replaced with halogen atoms, and may be a partially fluorinated hydrocarbon group or a fully fluorinated hydrocarbon group.

[0072] R 11 and R 12 These are independently -F, -CH3, -C2H5, -C3H7, -C6H5 (phenyl group), and -C6H n F 5-n (n is an integer from 0 to 4, and may be an integer from 0 to 3.) -CF3, -CH2CF3, -CH2CF3F7, -CH(CF3)2, -C(CF3)2-C6H5, -C(CF3)3, -C6H n (CF3) 5-n (n is an integer between 0 and 4, and can be either 1 or 2.)

[0073] In formula (B1b), the number of carbon atoms in the divalent hydrocarbon group or the divalent halogen-substituted hydrocarbon group may be 1 to 20, 1 to 15, 2 to 10, or 3 to 8. The halogen-substituted hydrocarbon group may be one in which some or all of the hydrogen atoms in the hydrocarbon group are replaced with halogen atoms, and may be a partially fluorinated hydrocarbon group or a fully fluorinated hydrocarbon group.

[0074] R 13 -C2H4-, -C3H6-, -C4H8-, -C5H 10 -, -C6H 12 -, -C7H 14 -, -C8H 16 -, -C9H 18 -, -C 10 H 20 Examples include those in which these hydrogen atoms are partially or completely replaced with fluorine. More specifically, -C(CH3)2-C(CH3)2- is preferred.

[0075] The molar ratio m of structural units (B) to total structural units contained in the polymer may be 0.2 to 0.8, 0.25 to 0.75, 0.3 to 0.7, 0.35 to 0.65, or 0.4 to 0.6.

[0076] The molar ratio n of structural unit (A) to total structural units contained in the polymer may be 0.25 to 0.75, 0.3 to 0.7, 0.35 to 0.65, or 0.4 to 0.6.

[0077] The sum of m and n is acceptable as long as it is 1 or less, but it may also be 0.95 or less. Furthermore, the sum of m and n may be 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, 0.9 or more, or 0.95 or more.

[0078] The content of structural units (A) relative to the total mass of the polymer may be 5 to 90% by mass, 20 to 80% by mass, 40 to 75% by mass, or 55 to 70% by mass.

[0079] The content of structural units (B) relative to the total mass of the polymer may be 10 to 95% by mass, 20 to 80% by mass, 25 to 60% by mass, or 30 to 45% by mass.

[0080] The total content of structural unit (A) and structural unit (B) may be 50% by mass or more, 70% by mass or more, 90% by mass or more, or 95% by mass or more, based on the total mass of the polymer.

[0081] The polymer may contain structural unit (C) which is different from both structural unit (A) and structural unit (B). Examples of structural unit (C) include structural unit (C1), structural unit (C2), and others. [ka] (In equation (C1), R 21 ~R 24 Each of these is a monovalent organic group, independently containing a hydrogen atom, a halogen atom, and 1 to 20 carbon atoms. * indicates the position where a structural unit (C1) is bonded to another structural unit. [ka] (In formula (C2), R 25 R is a divalent organic group having 1 to 20 carbon atoms. 26 and R 27 These are, respectively, monovalent organic groups having a hydrogen atom, a halogen atom, or 1 to 20 carbon atoms.

[0082] Furthermore, structural unit (C) may include structural units that are precursors to structural unit (A) (also called structural unit (Ap)). Examples of such structural units include unreacted structural units and intermediate structural units that could not be converted to structural unit (A) from structural units that are precursors to structural unit (A) (for example, structural units derived from monomer (A2') described later), for example, a group that is the conjugate acid of structural unit (A) (that is, an alkali metal ion that is the countercation of structural unit (A)) + Examples include those that have been replaced with , and groups in which the counter cation of structural unit (A) is replaced with a cation other than an alkali metal ion. Examples of counter cations included in structural unit (Ap) include NH4 + Examples include organic ammonium cations and metal ions such as alkaline earth metal ions. The polymer may contain 85 mol% or more, 90 mol% or more, or 95 mol% or more of structural unit (A) relative to the total amount of structural unit (A) and structural unit (Ap).

[0083] The polymer may contain structural units derived from hydrocarbon compounds having multiple ethylenically unsaturated groups, such as butadiene and isoprene.

[0084] The polymer may have structural units derived from the crosslinking agent. Examples of crosslinking agents include compounds having multiple ethylenically unsaturated groups in their molecules, such as hexanediol diacrylate, pentaerythritol tetraacrylate, divinylbenzene, and triethylene glycol divinyl ether.

[0085] The number-average molecular weight (Mn) of the polymer may be between 5,000 and 200,000, between 8,000 and 120,000, or between 10,000 and 100,000. The weight-average molecular weight (Mw) of the polymer may be between 5,000 and 300,000, between 10,000 and 250,000, or between 20,000 and 100,000. The molecular weight distribution (Mw / Mn) of the polymer may be between 1.0 and 3.5, or between 1.3 and 2.7. The number-average molecular weight and weight-average molecular weight of the polymer can be measured, for example, by gel permeation chromatography.

[0086] The polymer content in the electrolyte composition may be 0.5 to 40% by mass, 1 to 30% by mass, or 2 to 20% by mass. The polymer content in the electrolyte composition may be 1 to 50% by volume, 3 to 40% by volume, or 7 to 35% by volume.

[0087] The method for producing the polymer is not particularly limited, but examples include polymerizing a monomer (monomer mixture) that includes at least one of a monomer having an alkali metal ionized anionic functional group or a monomer having a precursor of said anionic functional group (hereinafter referred to as monomer (A')) and a monomer (B') having a functional group that functions as an anion receptor. The monomer may further include a monomer (C') that is different from monomer (A') and monomer (B').

[0088] Monomer (A') and monomer (B') may have ethylenically unsaturated groups. In this case, monomer (A') and monomer (B') can be polymerized by radical addition polymerization. In this case, the monomers can be polymerized in the presence of an initiator. That is, the polymerization reaction may be carried out in a polymerizable composition containing monomers and an initiator.

[0089] Monomer (A') is a monomer that induces structural unit (A) in a polymer. Examples of monomer (A') include monomer (A1') represented by formula (A1') and monomer (A2') represented by formula (A2'). [ka] (X, Y and M in equation (A1')) + This has the same meaning as equation (A1). [ka] (In equation (A2'), R 15 ~R 17R is the R in equation (A2). 15 ~R 17 It has the same meaning, and Y2' is Y in equation (A2). 2 A group that can derive a phenolic hydroxyl group corresponding to the -OM group possessed by, or Y 2 It is a group that has a group capable of deriving a sulfonic acid group corresponding to the -SO3M group that it possesses.

[0090] Y 2 ' is, Y 2 It may be the same base, but Y 2 It may be a precursor group of Y. 2 ' is the Y that you are trying to obtain 2 It is a group that has a group that can be converted to an -OM group or -SO3M group at the same position as the -OM group or -SO3M group that the other group possesses.

[0091] Y 2 Examples of groups that can derive a phenolic hydroxyl group corresponding to the -OM group possessed by include hydrolyzable groups, and by hydrolyzing the hydrolyzable group, Y 2 A phenolic hydroxyl group can be introduced at the position corresponding to the -OM group present. Examples of hydrolyzable groups include alkoxide groups or -OSi(R k )3 groups (R k Examples include monovalent organic groups such as hydrocarbon groups. Phenolic hydroxyl groups can be converted to -OM groups by reacting them with basic alkali metal salts such as MOH, M2CO3, and MHCO3.

[0092] Similarly, Y 2Groups that can derive a sulfonic acid group corresponding to the -SO3M group present in include, for example, sulfonic acid ester groups and groups that can derive a sulfonic acid group (-SO3H), such as -SO2Cl groups. Sulfonic acid groups can be converted to -OM groups by reacting them with alkali metal salts such as MOH, M2CO3, MHCO3, and alkali metal halides. In addition, -SO2Cl groups can be converted to -SO3M groups by reacting them with MOH. When an excess amount of MOH is used, almost all of the -SO2Cl groups can be converted to -SO3M groups. In such reactions, some of the -SO2Cl groups may become -SO3H groups, but the -SO3H groups may be reacted separately with a base containing M to form -SO3M groups. 2 ' is, Y 2 It may also be a group that has the same anionic moiety as and forms a salt with a cation other than an alkali metal ion. In this case, the structural unit (A2) can be derived by carrying out a cation exchange reaction on the resulting polymer. Reaction rate of Y2' (Y 2 Of the total amount of 'Y 2 The proportion of the converted product may be 85 mol% or more, 90 mol% or more, or 95 mol% or more.

[0093] Monomer (B') is a monomer that induces structural unit (B) in a polymer. Examples of monomer (B') include monomer (B') represented by the following formula (B'). [ka] (In the formula, R 1 ~R 3 And W is R in equation (B). 1 ~R 3 (And it has the same meaning as W.)

[0094] The radical polymerization initiator may be either a thermal initiator or a photoinitiator. For example, thermal initiators include azo initiators such as 2,2-azobis(isobutyronitrile) (AIBN), 2,2-azobis(2-methylbutyronitrile) (AMBN), 2,2-azobis(2,4-dimethylvaleronitrile) (ADVN), 1,1-azobis(1-cyclohexanecarbonitride) (ACHN, V-40), and dimethyl-2,2-azobisisobutyrate (MAIB); and organic peroxides such as dibenzoyl peroxide, di-8,5,5-trimethylhexanoyl peroxide, dilauroyl peroxide, didecanoyl peroxide, and di(2,4-dichlorobenzoyl) peroxide. Photoinitiators include oxime compounds, metallocene compounds, acylphosphine compounds, and aminoacetophenone compounds. One or more initiators may be used.

[0095] [Ionic liquid] The ionic liquid is not particularly limited and may be any liquid that can be used for applications such as batteries. Specifically, examples include imidazolium salts, pyrrolidinium salts, piperidinium salts, pyridinium salts, quaternary ammonium salts, and quaternary phosphonium salts. There are no particular restrictions on the anions that the ionic liquid possesses; for example, Cl - , Br - , I - ClO4 - PF6 - BF4 - CF3SO3 - , (FSO2)2N - , (CF3SO2)2N - , (C r F 2r+1 SO2)2N - (r is an integer greater than or equal to 2), HSO3 - These are some examples, and from the perspective of electrochemical stability, PF6 - BF4 - CF3SO3 - , (FSO2)2N - , (CF3SO2)2N - or (C m F 2m+1 SO2)2N- (CF3SO2)2N is preferred. - This is more preferable. The ionic liquid may be liquid at 25°C.

[0096] Examples of pyrrolidinium cations found in pyrrolidinium salts include the following: [ka] In the formula, R 41 and R 42 Each of these is independently a monovalent organic group, and it is preferable that the organic group has 1 to 15 carbon atoms. Examples of monovalent organic groups include alkyl groups having 1 to 15 carbon atoms, such as a butyl group, or formula:-A 1 -O-(A 2 -O) k -A 3 The group represented by (A 1 A is an alkylene group having one or two carbon atoms, 2 A is an alkylene group having 2 or 3 carbon atoms, 3 It is an alkyl group having 1 to 3 carbon atoms, and k is 0 to 3. Formula:-A 1 -O-(A 2 -O) k -A 3 The group represented by is preferably a group having 1 to 10 carbon atoms, and more preferably a -CH3OCH2CH2OCH3 group or a -CH2CH2-O-CH3 group. 41 R is an alkyl group having 1 to 3 carbon atoms, and may be a methyl group. 41 and R 42 These may be the same or different. Furthermore, the hydrogen atoms bonded to the carbon atoms constituting the pyrrolidine ring may be substituted with substituents.

[0097] Examples of piperidinium cations found in piperidinium salts include the following: [ka] In the formula, R 43 and R 44 Each of these is independently a monovalent organic group, and it is preferable that the organic group has 1 to 15 carbon atoms. The monovalent organic group is an alkyl group having 1 to 15 carbon atoms or formula:-A 1 -O-(A 2 -O) k -A 3 The group represented by (A 1 A is an alkylene group having one or two carbon atoms, 2 A is an alkylene group having 2 or 3 carbon atoms, 3 It is an alkyl group having 1 to 3 carbon atoms, and k is 0 to 3. R 44 The alkyl group is more preferably an alkyl group having 2 to 6 carbon atoms, such as a butyl group. Formula: -A 1 -O-(A 2 -O) k -A 3 The group represented by is preferably a group having 1 to 10 carbon atoms, and more preferably a -CH3OCH2CH2OCH3 group or a -CH2CH2-O-CH3 group. 43 R is an alkyl group having 1 to 3 carbon atoms, and may be a methyl group. 43 and R 44 These may be the same or different. Furthermore, the hydrogen atoms bonded to the carbon atoms constituting the piperidine ring may be substituted with substituents.

[0098] Examples of imidazolium cations found in imidazolium salts include the following: [ka] In the formula, R 46 and R 47 Each of these is independently a monovalent organic group, and it is preferable that the organic group has 1 to 15 carbon atoms. The monovalent organic group is an alkyl group having 1 to 15 carbon atoms or formula:-A 1 -O-(A 2 -O)k -A 3 The group represented by (A 1 A is an alkylene group having one or two carbon atoms, 2 A is an alkylene group having 2 or 3 carbon atoms, 3 It is an alkyl group having 1 to 3 carbon atoms, and k is 0 to 3. R 47 The alkyl group is preferably an alkyl group having 2 to 6 carbon atoms, such as a butyl group. Formula: -A 1 -O-(A 2 -O) k -A 3 The group represented by is preferably a group having 1 to 10 carbon atoms, and more preferably a -CH3OCH2CH2OCH3 group or a -CH2CH2-O-CH3 group. 46 R is an alkyl group having 1 to 3 carbon atoms, and may be a methyl group. 46 and R 47 These may be the same or different. Furthermore, the hydrogen atoms bonded to the carbon atoms constituting the imidazole ring may be substituted with substituents.

[0099] Examples of ammonium cations found in quaternary ammonium salts include the following: [ka] In the formula, R 51 ~R 54 Each of these is independently a monovalent organic group, and it is preferable that the organic group has 1 to 15 carbon atoms. The monovalent organic group is an alkyl group having 1 to 15 carbon atoms or a group of the formula:-A 1 -O-(A 2 -O) k -A 3 The group represented by (A 1 A is an alkylene group having one or two carbon atoms, 2 A is an alkylene group having 2 or 3 carbon atoms, 3It is preferable that it is an alkyl group having 1 to 3 carbon atoms, and k is 0 to 3. 51 ~R 54 They may all be the same, but they may also be two or more different groups. For example, R 51 R is an alkyl group having 1 to 10 carbon atoms, 52 ~R 54 It is preferable that R is an alkyl group having 1 to 3 carbon atoms, 51 R is an alkyl group having 3 to 8 carbon atoms, such as a butyl group. 52 ~R 54 It is more preferable that the group is a methyl group or an ethyl group. Formula: -A 1 -O-(A 2 -O) k -A 3 The group represented by is preferably a group having 1 to 10 carbon atoms, and more preferably a -CH3OCH2CH2OCH3 group or a -CH2CH2-O-CH3 group.

[0100] Examples of phosphonium cations found in quaternary phosphonium salts include the following: [ka] In the formula, R 56 ~R 59 Each of these is independently a monovalent organic group, and it is preferable that the organic group has 1 to 15 carbon atoms. The monovalent organic group is an alkyl group having 1 to 15 carbon atoms or a group of the formula:-A 1 -O-(A 2 -O) k -A 3 The group represented by (A 1 A is an alkylene group having one or two carbon atoms, 2 A is an alkylene group having 2 or 3 carbon atoms, 3 It is preferable that it is an alkyl group having 1 to 3 carbon atoms, and k is 0 to 3. 56 ~R 59 They may all be the same, but they may also be two or more different groups. For example, R 56R is an alkyl group having 1 to 10 carbon atoms, 57 ~R 59 It is preferable that R is an alkyl group having 1 to 3 carbon atoms, 56 R is an alkyl group having 3 to 8 carbon atoms, such as a pentyl group. 57 ~R 59 It is more preferable that it is a methyl group or an ethyl group.

[0101] Examples of ionic liquids include 1-(2-methoxyethoxymethyl)-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-n-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide, 1-n-butyl-1-methylpyrrolidinium trifluoromethanesulfonic acid, 1-n-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, triethyl-n-pentylphosphonium bis(trifluoromethylsulfonyl)imide, and n-butyltrimethylammonium bis(trifluoromethylsulfonyl)imide.

[0102] The ionic liquid content may be 1 to 50% by mass, 3 to 40% by mass, or 5 to 30% by mass, relative to the total amount of the electrolyte composition. The organic solvent content may be 1 to 70% by volume, 5 to 60% by volume, or 15 to 55% by volume, relative to the total amount of the electrolyte composition.

[0103] The electrolyte composition may contain metal salts in addition to the polymers mentioned above. The metal salt may be at least one of alkali metal salts and alkaline earth metal salts, and may be an alkali metal salt. The alkali metal salt is not particularly limited, but M can be MF, MCl, MBr, MI, MClO4, MPF6, MBF4, M2SO4, M[(C h F 2h+1 )SO3](h is 0~3), M[(C h F2h+1 Examples include )SO2]2N (h is 0-3). If the polymer has structural unit (A), M may be the same alkali metal element as the alkali metal element of structural unit (A). M may be lithium, sodium, or potassium, and may be lithium. Furthermore, if the polymer has functional group (B), the electrolyte composition may contain an alkali metal salt.

[0104] The electrolyte composition may further be a composite containing other resins such as fluororesins, fabrics such as nonwoven fabrics, porous materials, viscosity modifiers, etc. Examples of other resins include fluororesins. As for fluororesins, resins having carbon chains as the main chain are preferred. The carbon chains may be formed by radical polymerization of ethylenically unsaturated groups. Examples of fluororesins include poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and polyvinylidene fluoride (PVDF).

[0105] The total amount of the ion-conducting inorganic solid electrolyte, the polymer having the ability to preferentially conduct metal ions, and the ionic liquid in the electrolyte composition may be 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, 97% by mass or more, 99.9% by mass or less, or 99% by mass or less, relative to the total amount of the electrolyte composition. Furthermore, the total amount of the ion-conducting inorganic solid electrolyte, the polymer having the ability to preferentially conduct metal ions, and the ionic liquid in the electrolyte composition may be 70 to 99.9% by mass, or 80 to 99% by mass, relative to the total amount of the electrolyte composition. The total amount of the ion-conducting inorganic solid electrolyte, the polymer having the ability to preferentially conduct metal ions, and the ionic liquid in the electrolyte composition may be 70% or more by volume, 80% or more by volume, 90% or more by volume, 95% or more by volume, 97% or more by volume, 99.9% or less by volume, or 99% or less by volume, relative to the total amount of the electrolyte composition. Furthermore, the total amount of the ion-conducting inorganic solid electrolyte, the polymer having the ability to preferentially conduct metal ions, and the ionic liquid in the electrolyte composition may be 70 to 99.9% by volume, or 80 to 99% by volume, relative to the total amount of the electrolyte composition.

[0106] The ionic conductivity of the electrolyte composition of this embodiment at 25°C is 10 -4 S / cm or more is acceptable, and 2.0 × 10 -4 S / cm or more, 3.0 × 10 -4 S / cm or more is acceptable, and 5.0 × 10 -4 It may be S / cm or higher.

[0107] The activation energy of the electrolyte composition of this embodiment may be 30 kJ / mol or less, 28 kJ / mol or less, or 26 kJ / mol or less.

[0108] The electrolyte composition of this embodiment tends to be highly flexible. For example, the dynamic hardness DH of the electrolyte composition of this embodiment, calculated using the following formula based on the results of nanoindenter testing at 25°C, is 10 3 N / mm 2 The following may be true: 8.0 × 10 2 N / mm 2 The following may be true: 6.0 × 10 2 N / mm 2 The following may be true: 5.0 × 10 2 N / mm 2The following may apply: In the measurement using a nanoindenter, the test force required to reach a preset indentation depth h may be measured, or the indentation depth due to a preset test force may be measured. As a measurement sample for the nanoindenter, for example, a sheet-like sample with a diameter of 1.5 cm obtained by press-molding 150 mg of electrolyte composition at a pressure of 200 MPa may be used. The value of the dynamic hardness DH may be obtained from the average value of several test results (e.g., 5 points) measured so as not to overlap with each other. DH = α × F / h 2 ×10 3 α = 3.8584: Constant due to indenter shape F: Testing ability h: depth of indentation

[0109] The electrolyte composition of this embodiment can be used as a constituent material for electrochemical devices such as capacitors and batteries, and can be used, for example, as an electrolyte material for batteries. The electrolyte may be formed by pressure molding of the electrolyte composition. Examples of batteries include lithium-ion batteries and sodium-ion batteries, which charge and discharge by the movement of alkali metal ions. The battery may be a primary battery, a secondary battery, or an all-solid-state battery. The electrolyte composition of this embodiment may be a non-liquid electrolyte composition such as a solid electrolyte composition.

[0110] The battery of this embodiment includes a positive electrode, a negative electrode, and an electrolyte disposed between the positive and negative electrodes. The electrolyte may include the electrolyte composition of this embodiment. For example, in the case of a lithium-ion battery, the positive electrode is not particularly limited and may include a positive electrode active material and, if necessary, a conductive additive, a binder, etc. The positive electrode may be a layer containing these materials formed on a current collector. Examples of positive electrode active materials include lithium-containing composite metal oxides containing lithium (Li) and at least one transition metal selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, Cu, and Al. Examples of such lithium composite metal oxides include LiCoO2, LiNiO2, LiMn2O4, Li2MnO3, and LiNi x Mn y Co 1-x-y O2[0 <x+y<1])、LiNi x Co y Al 1-x-y O2[0 <x+y<1])、LiCr 0.5 Mn 0.5 Examples include O2, LiFePO4, Li2FeP2O7, LiMnPO4, LiFeBO3, Li3V2(PO4)3, Li2CuO2, Li2FeSiO4, and Li2MnSiO4.

[0111] The negative electrode of a lithium-ion battery is not particularly limited and may include a negative electrode active material and, if necessary, a conductive additive, a binder, etc. Examples include elemental elements such as Li, Si, P, Sn, Si-Mn, Si-Co, Si-Ni, In, and Au, as well as alloys or composites containing these elements, carbon materials such as graphite, and materials in which lithium ions are inserted between layers of the carbon material.

[0112] Lithium-ion batteries may have a separator. The separator may be a porous material, or a porous resin material. Specifically, examples include porous polyolefin films and porous ceramic films.

[0113] The method for producing the electrolyte composition is not particularly limited as long as it allows for the mixing of each component of the electrolyte composition. Examples include a method of mixing each component of the electrolyte composition in a mortar and pestle (solid-phase method) and a method of producing a precursor composition by dissolving and dispersing each component of the electrolyte composition in an organic solvent, and then removing the organic solvent from the precursor composition by drying or other means (liquid-phase method). The organic solvent used in the liquid-phase method may be an aprotic solvent, such as N-methyl-2-pyrrolidone. The amount of organic solvent used may be 200 to 2000 parts by mass or 500 to 1500 parts by mass per 100 parts by mass of the electrolyte composition to be produced. The ion-conducting inorganic solid electrolyte may be subjected to acid treatment before mixing with other components.

[0114] The battery manufacturing method of this embodiment may include, for example, a step of preparing an electrolyte composition (battery coating agent) and a step of pressurizing the electrolyte composition to produce an electrolyte. The produced electrolyte is placed between the positive electrode and the negative electrode. Pressurization may be performed with the electrolyte composition placed on the negative electrode or positive electrode, or between the positive and negative electrodes. Pressurization may also be performed with the electrolyte composition placed between the negative electrode and the positive electrode. The pressure during pressurization may be, for example, 10 to 300 MPa or 100 to 250 MPa. Pressurization may be performed at 10°C to 60°C or 20°C to 50°C. [Examples]

[0115] [Production of polymers that have the ability to preferentially conduct metal ions] First, monomer A1 was manufactured as follows. [ka]

[0116] (Synthesis of monomer A1) Under a nitrogen atmosphere, trifluoromethanesulfonamide (52.5 mmol, 7.83 g, manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in dehydrated acetonitrile (150 mL, manufactured by Kanto Chemical Co., Ltd.). To this solution, lithium hydroxide (105 mmol, 2.51 g, manufactured by Tokyo Chemical Industry Co., Ltd.) and 4-acetamidobenzenesulfonyl chloride (50 mmol, 11.68 g, manufactured by Tokyo Chemical Industry Co., Ltd.) were added sequentially and the mixture was heated under reflux for 5 hours. After cooling to room temperature, an excess amount of acetonitrile (700 mL) was added to precipitate the solid, which was separated by filtration and washed with dichloromethane (manufactured by Kanto Chemical Co., Ltd.) to obtain intermediate 1. The yield was 97.1%. • Structural formula of intermediate 1: [ka]

[0117] Under a nitrogen atmosphere, 5% hydrochloric acid (22.5 mL) was added to intermediate 1 (15 mmol, 5.28 g) and stirred at 90°C for 2 hours. After cooling to room temperature, lithium hydroxide aqueous solution was added until the pH reached 7 or higher, as confirmed by pH test paper, and then a solid was obtained by vacuum drying. The obtained solid was extracted with acetonitrile solution and vacuum drying was obtained to obtain intermediate 2. The yield was 92.6% based on the raw materials of intermediate 1. • Structural formula of intermediate 2: [ka]

[0118] Under a nitrogen atmosphere, maleic anhydride (13.3 mmol, 1.30 g, manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in dehydrated 1,4-dioxane (manufactured by Kanto Chemical Co., Ltd.). To this solution, the entire volume of a solution of intermediate 2 (13.2 mmol, 4.09 g) prepared under a nitrogen atmosphere in dehydrated tetrahydrofuran (26.4 mL, manufactured by Kanto Chemical Co., Ltd.) was added dropwise, and the mixture was stirred at room temperature for 12 hours. After the reaction, the precipitate was filtered and vacuum-dried at 60°C for 4 hours to obtain a solid containing intermediate 3. • Structural formula of intermediate 3: [ka]

[0119] Under a nitrogen atmosphere, a solid containing Intermediate 3 (14.0 mmol, 5.70 g) and an aqueous sodium acetate solution (13.3 mmol, 1.09 g, manufactured by Tokyo Chemical Industry Co., Ltd.) were added to acetic anhydride (12.3 mL, manufactured by Tokyo Chemical Industry Co., Ltd.), and the mixture was stirred at 70 °C for 3 hours. The reaction solution was dropwise added in its entirety to an excess amount of diethyl ether (manufactured by Kanto Chemical Co., Inc.) at 0 °C, and the precipitate was collected by filtration. Under an inert atmosphere, the precipitate was extracted with dehydrated acetonitrile (manufactured by Kanto Chemical Co., Inc.) and dried under reduced pressure to obtain Monomer A1. The yield through all steps was 72.8%.

[0120] (Polymer 1) 0.936 g of Monomer A1, 1.53 g of n-dodecyl vinyl ether, and 16.4 mg of AIBN were dissolved in 20 mL of dehydrated acetonitrile, and tetralin was added as an internal standard substance. While confirming the monomer consumption rate, the reaction was carried out at 60 °C for 24 hours under a nitrogen atmosphere. The polymerization solution was dialyzed in acetonitrile and dried under vacuum at 120 °C to obtain 0.637 g (yield 44%) of Polymer 1. The monomer introduction ratio was A1:n-dodecyl vinyl ether = 55:45. The monomer introduction ratio was calculated from the 1 1H-NMR of the copolymer. As for n-dodecyl vinyl ether, a commercially available reagent with a purity >98% manufactured by Aldrich was sealed with CaCl2 and dried overnight, and then CaH2 was added and the purity was improved by distillation under reduced pressure before use. In Polymer 1, the number average molecular weight Mn = 4.9×10 4 and the weight average molecular weight Mw = 7.9×10 4 with a molecular weight distribution Mw / Mn = 1.63.

[0121] (Polymer 2) Monomer A1: 1.17 g, tetraethylene glycol methyl vinyl ether: 2.25 g, AIBN: 24.6 mg were dissolved in 30 mL of dehydrated acetonitrile. Tetralin was added as an internal standard substance, and the reaction was carried out at 60 °C for 24 hours under a nitrogen atmosphere while confirming the monomer consumption rate. The polymerization solution was dialyzed in acetonitrile and vacuum dried at 120 °C to obtain 1.49 g (yield 79%) of Polymer 2. The monomer introduction ratio was A1:tetraethylene glycol methyl vinyl ether = 41:59. The monomer introduction ratio of the copolymer was 1 Calculated from 1H-NMR. As tetraethylene glycol methyl vinyl ether, a commercially available reagent with a purity >98% manufactured by Aldrich was used as it was. For Polymer 2, the number average molecular weight Mn = 1.4×10 4 and the weight average molecular weight Mw = 2.7×10 4 with a molecular weight distribution Mw / Mn = 1.85.

[0122] (Polymer 3) Monomer A1: 3.121 g, styrene: 0.833 g, AIBN: 57.5 mg were dissolved in 70 mL of dehydrated acetonitrile. Tetralin was added as an internal standard substance, and the reaction was carried out at 60 °C for 24 hours under a nitrogen atmosphere while confirming the monomer consumption rate. The polymerization solution was dialyzed in acetonitrile and vacuum dried at 120 °C to obtain 3.50 g (yield 89%) of the polymer. The monomer introduction ratio was A1:styrene = 54:46. The monomer introduction ratio of the copolymer was 1 Calculated from 1H-NMR. As styrene, a commercially available reagent with a purity >98% manufactured by Aldrich was sealed with CaCl2 and dried overnight, and then CaH2 was added and distilled under reduced pressure to improve the purity before use. For the synthesized polymer, the number average molecular weight Mn = 9.3×10 4 and the weight average molecular weight Mw = 3.0×10 5 with a molecular weight distribution Mw / Mn = 3.19.

[0123] [Ionic Conductive Inorganic Solid Electrolyte] As the ionic conductive inorganic solid electrolyte, LLZT powder: manufactured by Toyoshima Seisakusho Co., Ltd., Li 6.6La3Zr 1.6 Ta 0.4 O 12 I used it.

[0124] (Example 1) A gel-like polymer composition was prepared by mixing 6 parts by mass of polymer 1 with 13 parts by mass of ethylmethylimidazolium bisfluorosulfonylimide (EMIFSI). Next, a mixture was obtained by ball milling 81 parts by mass of LLZT powder and 19 parts by mass of the gel-like polymer composition at room temperature (25°C) and 300 rpm for 4 hours. An electrolyte composition with a diameter of 1.5 cm was obtained by press molding 150 mg of the above mixture at a pressure of 200 MPa (solid-phase method).

[0125] (Example 2) The electrolyte composition was prepared in the same manner as in Example 1, except that polymer 1 was replaced with polymer 2.

[0126] (Example 3) Six parts by mass of polymer 1, thirteen parts by mass of ethylmethylimidazolium bisfluorosulfonylimide (EMIFSI), and 81 parts by mass of LLZT powder were mixed in 1000 parts by mass of N-methyl-2-pyrrolidone, and the solvent was removed by drying to obtain a mixture. 150 mg of the above mixture was press-molded at a pressure of 200 MPa to obtain an electrolyte composition with a diameter of 1.5 cm (liquid phase method).

[0127] (Comparative Example 1) As the electrolyte composition, a 1.5 cm diameter pellet was used, obtained by press-molding 150 mg of LLZT powder at a pressure of 200 MPa.

[0128] (Comparative Example 2) LLZT sintered body: Manufactured by Toyoshima Seisakusho Co., Ltd., Li 6.6 La3Zr 1.6 Ta 0.4 O 12 3N Φ10×0.5mmt was used as is.

[0129] (Comparative Example 3) An electrolyte composition was prepared in the same manner as in Example 1, except that 6 parts by mass of a mixture of Aldrich polyethylene oxide (Poly(ethylene oxide) average Mv 600,000, powder) and lithium bisfluorosulfonylimide (LiFSI) (molar ratio of O atoms:Li atoms = 20:1) was used instead of polymer 1.

[0130] <Measurement of ionic conductivity> An evaluation cell for a CR2032 coin cell was assembled inside a glove box under a dry argon atmosphere. Specifically, a test laminate was created by stacking each layer in the following order within the evaluation cell. (Stainless steel plate / Electrolyte composition / Stainless steel plate) The impedance is measured using an impedance measuring device under the following conditions: 25°C, frequency range 0.1Hz to 1MHz, and applied voltage 10mV (vs. open-circuit voltage). The ionic conductivity σ can be calculated using the following formula. σ(S·cm -1 ) = t(cm) / (R(Ω) × A(cm) 2 )) In the formula, R represents the impedance value, A represents the sample area, and t represents the sample thickness. The results are shown in Table 1.

[0131] <Measurement of activation energy> Ionic conductivity measurements using the evaluation cell described above were also performed under conditions of 30, 40, 50, 60, and 70°C to measure the change in ionic conductivity with respect to temperature. The activation energy was calculated from the slope of the graph of the common logarithm of ionic conductivity and the reciprocal of temperature using the Arrhenius equation (logk = logA - Ea / RT, where k is the reaction rate constant, A is the frequency factor, Ea is the activation energy, R is the gas constant, and T is the absolute temperature). The results are shown in Table 1.

[0132] [Table 1]

[0133] (Examples 4 and 5) An electrolyte composition was produced in the same manner as in Example 3 except that the compounding amounts (weight ratios) of the respective components were changed as described in Table 2, and the ionic conductivity at 25°C was measured.

[0134] <Measurement of Dynamic Hardness> The mechanical properties of the electrolyte composition were measured using a nanoindenter DUH-211 manufactured by Shimadzu Corporation. The dynamic hardness was calculated as follows from the value of the test force F when the indentation depth h was 3 μm. The same measurement was carried out at 5 non-consecutive points per sample, and the average value was calculated. The results are shown in Table 2. The test was conducted at 25°C. Dynamic hardness DH (N / mm 2 ) DH = α × F / h 2 × 10 3 α = 3.8584: Constant depending on the indenter shape F: Test force (mN) h: Indentation depth (μm)

[0135]

Table 2

Claims

1. Ion-conducting inorganic solid electrolytes, A polymer having the ability to preferentially conduct metal ions, It contains an ionic liquid, The polymer is an electrolyte composition comprising an anionic functional group having a metal ion as a countercation.

2. The electrolyte composition according to claim 1, wherein the ion-conducting inorganic solid electrolyte is an oxide, sulfide, hydride, or halide containing at least one of an alkali metal element and an alkaline earth metal.

3. The electrolyte composition according to claim 2, wherein the ion-conducting inorganic solid electrolyte is a perovskite-type oxide, a NASICON-type oxide, a LISICON-type oxide, or a garnet-type oxide.

4. The electrolyte composition according to claim 1 or 2, wherein the polymer further comprises a functional group having anion-scavenging ability.

5. The ionic conductivity at 25°C is 10 －４ The electrolyte composition according to claim 1 or 2, wherein the S / cm is 1 or higher.

6. The electrolyte composition according to claim 1 or 2, wherein the activation energy is 30 kJ / mol or less.

7. The dynamic hardness DH calculated from the following formula using the results of nanoindenter tests at 25°C is 10 ３ N / mm ２ The following is the electrolyte composition. DH=α×F / g ２ ×10 ３ α＝３．８５８４ F: Test power h: depth of indentation

8. An electrolyte comprising the electrolyte composition according to claim 1 or 2.

9. A battery comprising the electrolyte composition according to claim 1 or 2.

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