Electrolyte composition, electrode composition, and battery

Abstract

The present disclosure provides an electrolyte composition which contains a polymer, an organic solvent, and particles, wherein the polymer has a side group that comprises one or more groups selected from the group consisting of an alkali metallized phenolic group, an alkali metallized carboxylic acid group, an alkali metallized sulfonic acid group, and an alkali metallized sulfonyl imide group.

Description

Electrolyte composition, electrode composition, and battery

[0001] The present disclosure relates to electrolyte compositions, electrode compositions, and batteries.

[0002] Batteries such as lithium-ion batteries, which charge and discharge through the transfer of metal ions between a positive electrode and a negative electrode, have been the subject of vigorous research due to their high capacity. Known electrolytes used in lithium-ion batteries include solutions of lithium salts containing organic solvents or ionic liquids. However, from the perspectives of safety and processability, research into solid electrolytes, polymer electrolytes, and the like is also underway (see Patent Documents 1 and 2). In addition to lithium-ion batteries, research is also underway into batteries using other alkali ions, such as sodium and potassium, which are more abundant than lithium.

[0003] Korean Patent Publication No. 10-2016-0050870 Special Publication No. 2023-511906

[0004] Here, electrolytes used in lithium ion batteries and the like are required to have the property of being able to pass a larger current with a small overvoltage. However, when a large current is passed through an electrolyte composition containing a polymer, the overvoltage increases rapidly due to low ionic conductivity, non-uniformity of the electrolyte, and the like, and there is still room for improvement in such properties.

[0005] The present disclosure has been made in view of the above circumstances, and aims to provide an electrolyte composition, an electrode composition, and a battery including the same that are capable of passing a larger current with a small overvoltage.

[0006] The present disclosure includes the following exemplary embodiments. [1] An electrolyte composition comprising a polymer, an organic solvent, and particles, wherein the polymer has side groups containing one or more groups selected from the group consisting of an alkali metal phenol group, an alkali metal carboxylic acid group, an alkali metal sulfonic acid group, and an alkali metal sulfonylimide group. [2] The electrolyte composition of [1], wherein the particles are nanoparticles. [3] The electrolyte composition of [1] or [2], wherein the side groups contain lithium ions or sodium ions. [4] The electrolyte composition of any one of [1] to [3], wherein the organic solvent contains one or more solvents selected from the group consisting of carbonate-based solvents, ether-based solvents, fluorine-based solvents, nitrile-based solvents, lactone-based solvents, and phosphate ester-based solvents. [5] The electrolyte composition of any one of [1] to [4], wherein the side groups contain one or more groups selected from the group consisting of a lithiated phenol group, a lithiated carboxylic acid group, a lithiated sulfonic acid group, and a lithiated sulfonylimide group. [6] The electrolyte composition according to any one of [1] to [5], further comprising an alkali metal salt. [7] The electrolyte composition according to any one of [1] to [6], having a transference number of 0.5 or more. [8] The electrolyte composition according to any one of [1] to [7], wherein the particles comprise one or more particles selected from the group consisting of carbon particles, sulfur particles, silicon oxide particles, aluminum oxide particles, titanium oxide particles, and organic particles. [9] The electrolyte composition according to any one of [1] to [8], wherein the content of the particles is 50 mass% or less with respect to the total amount of the electrolyte composition.

[10] An electrode composition comprising the electrolyte composition according to any one of [1] to [9].

[11] A battery comprising the electrolyte composition according to any one of [1] to [9].

[0007] According to the present disclosure, it is possible to provide an electrolyte composition, an electrode composition, and a battery including the same that are capable of passing a larger current with a small overvoltage.

[0008] FIG. 1 is a graph showing the relationship between the number of cycles and the voltage value in a lithium dissolution and deposition test.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings where appropriate. However, the following embodiments are merely examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents.

[0010] (Electrolyte Composition) The electrolyte composition of this embodiment contains a polymer, an organic solvent, and particles, and the polymer has a side group containing one or more groups selected from the group consisting of an alkali metal phenol group, an alkali metal carboxylic acid group, an alkali metal sulfonic acid group, and an alkali metal sulfonylimide group. In this specification, the group containing one or more groups selected from the group consisting of an alkali metal phenol group, an alkali metal carboxylic acid group, an alkali metal sulfonic acid group, and an alkali metal sulfonylimide group is also referred to as functional group (A), and a polymer having the functional group (A) as a side group is also referred to as polymer (A).

[0011] In the present specification, in any case, examples of the "substituent" include both organic groups and groups other than organic groups (inorganic groups). In the present specification, the term "organic group" refers to a group having a chemical structure in which at least one hydrogen atom has been removed from an organic compound. In the present specification, the term "organic group" refers to, in any case, a hydrocarbon group or a group in which some carbon atoms of a hydrocarbon group have been replaced with heteroatoms, a group in which at least one hydrogen atom of a hydrocarbon group or a group in which some carbon atoms of a hydrocarbon group have been replaced with heteroatoms, and the like, regardless of the valence of the organic group. When the organic group has a ring structure, the ring may be either a heterocycle or a carbocycle, and may be either a monocycle or a fused ring. In any case herein, examples of the hydrocarbon group include both an aliphatic hydrocarbon group and an aromatic hydrocarbon group. In any case herein, examples of the aliphatic hydrocarbon group include a linear hydrocarbon group, a branched hydrocarbon group, and a cyclic hydrocarbon group. Furthermore, in any case herein, examples of the hydrocarbon group include both a saturated hydrocarbon group and an unsaturated hydrocarbon group. In this specification, an aromatic hydrocarbon group refers to a hydrocarbon group having an aromatic moiety such as a benzene ring, and may also have an aliphatic moiety. Furthermore, in this specification, a cyclic hydrocarbon group refers to a hydrocarbon group having an aliphatic carbon ring moiety, and may also have a linear or branched aliphatic moiety. The heteroatom substituting the carbon atom is not particularly limited, and examples thereof include a boron atom, an oxygen atom, a nitrogen atom, a silicon atom, a phosphorus atom, and a sulfur atom. Specifically, the organic group may contain a linking group containing a heteroatom, such as an -O- (ether bond), an -S- (thioether bond), a sulfonyl group, a sulfinyl group, a secondary amino group, or a tertiary amino group. In any case in this specification, specific examples of the organic group include a substituted or unsubstituted hydrocarbon group, and a linking group in which one or more carbon atoms (methylene groups) in the hydrocarbon group contain a heteroatom such as —O— (ether bond), —S— (thioether bond), —C(═O)—, —C(═O)O—, or —C(═O)NR— (R is a monovalent organic group) (the linking group may be a divalent linking group).In any case herein, examples of the inorganic group include an electron-withdrawing group and an electron-donating group, and specific examples thereof include a halogen atom and —NH. ２ , -NH ３ ＋ , —CN, sulfonic acid group and its salts or esters, —NO ２ etc.

[0012] <Polymer: Polymer Capable of Preferentially Conducting Alkali Metal Ions> The polymer (A) may be a polymer capable of preferentially conducting alkali metal ions. A polymer capable of preferentially conducting alkali metal ions may be one that satisfies at least one of the following conditions (X) and (Y). The polymer may simply be referred to as a polymer capable of conducting alkali metal ions. Condition (X): When the transference number of alkali metal ions is measured at room temperature (25°C) for a composition containing 33 mass% of polymer and 67 mass% of nonionic plasticizer, the transference number of alkali metal ions is 0.4 or greater. Condition (Y): When the transference number of alkali metal ions is measured at room temperature (25°C) for a composition containing 31.9 mass% of polymer, an alkali metal salt, and the remaining total amount of nonionic plasticizer, and having an alkali metal ion concentration of 0.3 mol / L, the transference number of alkali metal ions is 0.4 or greater.

[0013] The polymer (A) may be one in which the transference number of the alkali metal ion under the above conditions (X) and (Y) is, for example, 0.5 or more, 0.6 or more, or 0.7 or more. The alkali metal ion contained in the composition for which the transference number is to be measured under the above conditions (X) and (Y) may be a counter cation of the anionic functional group of the polymer. Examples of nonionic plasticizers include at least one of an organic solvent and another resin such as a fluororesin. 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-based solvents, and ether-based solvents. The organic solvent may be a mixed solvent of ethylene carbonate and propylene carbonate (volume ratio 1:1). The fluororesin is preferably a resin having a carbon chain as the main chain. The carbon chain may be formed by radical polymerization of an ethylenically unsaturated group. The fluororesin may be PVDF-HFP.

[0014] The polymer (A) contains an alkali metalated group as a side group. Here, in this specification, the alkali metalated group refers to a group in which an anionic functional group, which is a conjugate base of the acid form of the group, forms a salt with an alkali metal ion. Specifically, the alkali metalated phenolic hydroxyl group is an -OA group (-O － A ＋ An alkali metal carboxylic acid group refers to a —COOA group ([—COO] group) in which H of a carboxylic acid group (—COOH group) is substituted with an alkali metal element A, for example. － A ＋ The alkali metal sulfonic acid group refers to a sulfonic acid group (-SO ３ H group) in which H is replaced by an alkali metal element A. ３ A group ([-SO ３ ] － A ＋ The alkali metal sulfonylimide group refers to a sulfonylimide acid group (-SO ２ -NH-SO２ - group) in which H is substituted with an alkali metal element A ２ -NA-SO ２ - group ([-SO ２ -N-SO ２ -] － A ＋ group), and examples thereof include a lithiated sulfonylimide group.

[0015] The structure of the polymer (A) is not particularly limited, but examples thereof include those having a carbon chain as the main chain, and the carbon chain may be formed by radical addition polymerization of a monomer having an ethylenically unsaturated group.

[0016] The alkali metal element A may contain at least one selected from the group consisting of lithium, sodium, potassium, rubidium, and cesium, may contain at least one selected from the group consisting of lithium, sodium, and potassium, may contain at least one of lithium and sodium, or may contain lithium.

[0017] The content of one alkali metal element among the alkali metal elements contained in the polymer (A) may be 80 mol% or more, 85 mol% or more, or 90 mol% or more, and the one alkali metal element may be potassium, sodium, or lithium, or may be sodium or lithium, or may be lithium.

[0018] The polymer (A) may have a structural unit (A). The structural unit (A) is a structural unit having a functional group (A), and may include at least one of a structural unit represented by the following formula (A1) and a structural unit represented by the following formula (A2). In formula (A1), R １ ~R ３ and Y are omitted, and in formula (A2), R ４ , R ５ The structure excluding Z is also simply called an ethylene unit. (In formula (A1), Y is a monovalent group modified with an alkali metal and contains a functional group (A). R １ ~R ３ are each independently a hydrogen atom or a monovalent substituent, or R１ and R ２ One of them is R ３ and form a ring together, and the other is a hydrogen atom or a monovalent substituent. １ ~R ３ may have an alkali metal group. １ ~R ３ At least one of may be a functional group other than a hydrogen atom or a fluorine atom. (In formula (A2), Z is a divalent group modified with an alkali metal and contains a functional group (A). R ４ and R ５ are each independently a hydrogen atom or a monovalent substituent, or R ４ and R ５ are joined together to form a ring. ４ and R ５ may have an alkali metalated group.

[0019] In formula (A1), Y contains at least the functional group (A), which may contain at least one of an alkali metal carboxylic acid group and an alkali metal phenolic hydroxyl group. The polymer (A) may contain one or more structural units (A) having different functional groups as Y.

[0020] In formula (A1), R １ ~R ３ When R is a monovalent substituent, the substituent may be a monovalent organic group. The number of carbon atoms in the monovalent organic group may be, for example, 1 to 20, 1 to 15, 1 to 10, 1 to 5, or 1 to 3. In formula (A1), R １ ~R ３ At least one of may be a hydrogen atom, or all of may be hydrogen atoms.

[0021] In formula (A1), R １ and R ２ One of them is R ３ When R forms a ring together with １ or R ２ and R ３In formula (A2), R forms a divalent substituent bonded to two carbon atoms of the ethylene unit of formula (A1). ４ and R ５ are taken together to form a ring, R ４ and R ５ form divalent substituents bonded to two carbon atoms of the ethylene unit of formula (A1), respectively. These rings may be either carbocyclic or heterocyclic. The number of ring members of these rings may be, for example, 4 to 10, 5 to 8, 5, or 6. A substituent may be bonded to the carbon atom or heteroatom that is a ring member.

[0022] When Y in formula (A1) contains an alkali metal-modified carboxylic acid group (-COOA group, A is an alkali metal), Y may be the -COOA group itself, or may be a monovalent organic group having a -COOA group. When Y is a monovalent organic group having a -COOA group, the number of carbon atoms in the organic group may be, for example, 1 to 20, 1 to 15, 1 to 10, 1 to 5, or 1 to 3. The number of carbon atoms in the organic group includes the number of carbon atoms constituting the -COOA group. The monovalent organic group having a -COOA group may have one or more -COOA groups, or may have one -COOA group. When Y is a monovalent organic group having a -COOA group, Y may have an electron-withdrawing group such as a halogen atom in addition to the -COOA group.

[0023] In formula (A1), Y is -R ９ -COOA, where R ９ is a divalent organic group or a covalent bond (i.e., Y is the -COOA group itself). The number of carbon atoms in the divalent organic group may be, for example, 1 to 19, 1 to 14, 1 to 9, 1 to 4, 1, or 2. ９ When contains a carbon atom, R ９ is R ９ may be a divalent group other than a group in which all carbon atoms included in R are substituted with fluorine atoms. ９ When contains a carbon atom, R ９ At least one of the carbon atoms contained in is bonded to a hydrogen atom or a substituent other than a fluorine atom.

[0024] When Y in formula (A1) has an alkali metal-substituted phenolic hydroxyl group, Y is, for example, R １０ -Y ２ where R １０ is a divalent substituent (linking group) or a covalent bond, and may be a covalent bond. ２ may be a group having one or more -OA groups (A is an alkali metal element) directly bonded to a carbon atom that is a member of an aromatic ring such as a benzene ring, a naphthalene ring, or an anthracene ring. The aromatic ring may be condensed with another ring structure. For example, Y ２ may have a group represented by any one of the following formulae (A21) to (A26). (In formula (A21), R Ａ１ ~R Ａ５ At least one of the groups is an -OA group, and the rest are hydrogen atoms or monovalent substituents. Ａ３ In formula (A22), R Ｂ１～ R Ｂ７ At least one of the groups is an -OA group, and the rest are hydrogen atoms or monovalent substituents. Ｂ３ ~R Ｂ６ At least one of the groups may be an —OA group. Ｃ１～ R Ｃ９ At least one of the groups is an -OA group, and the rest are hydrogen atoms or monovalent substituents. Ｃ２ ~R Ｃ８ At least one of the groups may be an —OA group. Ｄ１～ R Ｄ６ At least one of the groups is an -OA group, and the rest are hydrogen atoms or monovalent substituents. Ｄ３～ R Ｄ６ At least one of the groups may be an —OA group. Ｅ１～ R Ｅ９ At least one of the groups is an -OA group, and the rest are hydrogen atoms or monovalent substituents. Ｅ２ ~R Ｅ８ At least one of the groups may be an —OA group. Ｆ１～ RＦ９ At least one of the groups is an -OA group, and the rest are hydrogen atoms or monovalent substituents. Ｆ１～ R Ｆ９ At least one of the groups may be an —OA group.

[0025] The groups represented by formulae (A21) to (A26) have at least one -OA group, and the number of -OA groups may be, for example, 1 to 3, 1, or 2, or may be 1 -OA group.

[0026] In formulae (A21) to (A26), the monovalent substituent is preferably an electron-withdrawing group. Examples of the electron-withdrawing group include a halogen atom, a sulfonic acid group or a salt thereof, a sulfonic acid ester, a nitro group, and a nitrile group. The halogen atom may be any of F, Cl, Br, and I.

[0027] In formulae (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, for example, 1 to 15, 1 to 10, 1 to 5, or 1 to 3.

[0028] In formula (A1), Y is R １０ -Y ２ is a group represented by the formula １０ When R is a divalent substituent, the substituent may be a divalent organic group. The number of carbon atoms in the divalent organic group may be, for example, 1 to 15, 1 to 10, 1 to 8, or 1 to 5. １０ may have a heterocyclic ring or a ring having an imide group.

[0029] When Y in formula (A1) is a sulfonic acid group modified with an alkali metal, examples of Y include a group represented by the following formula (A3). (In formula (A3), R １９ is a covalent bond or a divalent organic group. A is an alkali metal element.

[0030] In formula (A3), the number of carbon atoms in the divalent organic group may be, for example, 1 to 20, 1 to 15, 1 to 10, 1 to 6, 1 to 5, or 1 to 3. １９ is a divalent organic group, and when the divalent organic group is a hydrocarbon group, at least one of the carbon atoms constituting the hydrocarbon group is bonded to a hydrogen atom. That is, the divalent organic group in formula (A3) is a group other than a perfluorinated hydrocarbon group.

[0031] The alkali metal sulfonic acid group represented by formula (A3) is, for example, —SO ３ A, -CH ２ -SO ３ A and -C ６ H ４ -SO ３ Examples include A.

[0032] When Y in formula (A1) is a sulfonylimide group modified with an alkali metal, examples of Y include a group represented by the following formula (A4). (In formula (A4), R ２０ is a covalent bond or a divalent organic group, and R ２１ is a hydrogen atom or a monovalent substituent. ＋ is an alkali metal ion.)

[0033] R in formula (A4) ２０ When is a divalent organic group, the number of carbon atoms in the divalent organic group may be, for example, 1 to 20, 1 to 15, 1 to 10, 1 to 6, 1 to 5, or 1 to 3.

[0034] When the structural unit (A) of the polymer (A) has a structural unit represented by formula (A2), in formula (A2), Z bonds to two carbon atoms of the ethylene unit to form a ring. The ring may be either a carbocyclic ring or a heterocyclic ring. Furthermore, the ring may be either aliphatic or aromatic. Examples of heterocyclic rings include rings having an imide group, such as a maleimide ring. A functional group (A) may be bonded to the ring. The number of carbon atoms in Z may be, for example, 1 to 20, 1 to 15, 2 to 10, or 3 to 8.

[0035] The structural unit (A2) may be a group containing a maleimide ring having an alkali metal-substituted group, and examples thereof include the following structural unit (A5). (In formula (A5), X is a divalent organic group having 1 to 20 carbon atoms, and Y １ is a halogen atom or a monovalent organic group having 1 to 20 carbon atoms, and A ＋ represents an alkali metal ion, and * represents the position where the structural unit (A5) is bonded to another structural unit.

[0036] The number of carbon atoms owned by X in formula (A5) may be, for example, 1 to 15, 2 to 10, or 3 to 8. When X is a hydrocarbon group, the hydrocarbon group may be, for example, 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 of these groups have been substituted with halogen atoms such as fluorine atoms, or a phenylene group or a substituted phenylene group substituted with an alkyl group, a halogen atom, an electron-withdrawing group, or the like.

[0037] Y in formula (A5) １ is a monovalent organic group, Y １ The number of carbon atoms contained in Y in formula (A5) may be, for example, 1 to 15, 1 to 10, 1 to 8, 1 to 5, or 1 to 3. １ When Y is a hydrocarbon group, the hydrocarbon group may be 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 of these groups have been substituted with halogen atoms such as fluorine atoms, or may be a fluorinated alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 3 carbon atoms such as a trifluoromethyl group. The fluorinated alkyl group may be a perfluorinated alkyl group. １ When is a halogen atom, the halogen atom may be a fluorine atom or a chlorine atom, and may be a fluorine atom.

[0038] When the structural unit (A) of the polymer (A) has a structural unit represented by formula (A2), and when formula (A2) contains a sulfonic acid group modified with an alkali metal, examples of Z in formula (A2) include a group represented by formula (A6) below. (In formula (A6), R １８ is a covalent bond or a divalent organic group. A is an alkali metal element.

[0039] In formula (A6), the divalent organic group may have, for example, 1 to 20, 1 to 15, 1 to 10, 1 to 6, 1 to 5, or 1 to 3 carbon atoms. １８ When contains a carbon atom, R １８ is R １８ may be a divalent group other than a group in which all carbon atoms included in R are substituted with fluorine atoms. １８ When contains a carbon atom, R １８ At least one of the carbon atoms contained in is bonded to a hydrogen atom or a substituent other than a fluorine atom.

[0040] The alkali metal sulfonic acid group represented by formula (A6) is, for example, —SO ３ A, -CH ２ -SO ３ A and -C ６ H ４ -SO ３ Examples include A.

[0041] The polymer (A) may have an alkali metal-modified group other than the functional group (A) (hereinafter also referred to as functional group (A')). Examples of such groups include an alkali metal-modified alcohol group and an alkali metal-modified phosphate group. The functional group (A') may be contained in the structural unit (A), or may be contained in a structural unit other than the structural unit (A) (i.e., a structural unit that does not have the functional group (A) but has the functional group (A'), and does not fall under any of the structural units (B) described below; hereinafter also referred to as structural unit (A')). The polymer (A) may also contain a structural unit having a functional group that functions as an anion receptor (hereinafter also referred to as structural unit (B)).

[0042] The electrolyte composition according to this embodiment may contain, in addition to the polymer (A), another polymer that does not contain the functional group (A) but has the ability to preferentially conduct alkali metal ions. Examples of the other polymer include a polymer containing at least one of the structural unit (A') and the structural unit (B) (hereinafter referred to as polymer (B)). The polymer (B) does not contain the functional group (A).

[0043] The structural unit (B) functions as an anion receptor, which is a chemical species that captures anions by forming electrostatic interactions, hydrogen bonds, acid-base complexes, or the like with anions.

[0044] The structural unit (B) captures the counter anion of the alkali metal ion in the alkali metal salt and promotes dissociation of the counter anion from the alkali metal ion. This increases the mobility of the alkali metal ion. Meanwhile, the counter anion is captured by the polymer via the structural unit (B), decreasing the mobility of the counter anion. As a result, it is believed that the transport number of the alkali metal ion is improved. Furthermore, since the mobility of the alkali metal ion is increased, the conductivity of the alkali metal ion also tends to improve. Low-molecular-weight chemical species (compounds, etc.) that function as anion receptors are known, and examples of such compounds include those described in U.S. Patent Nos. 6,022,643, 5,705,689, and 6,120,941.

[0045] The functional group functioning as an anion receptor may have Lewis acidity. In this case, the functional group can capture the anion by accepting the unshared electron pair of the anion and forming an acid-base complex. Examples of such functional groups include functional groups having an electron-deficient atom. Note that an electron-deficient atom refers to an atom that is covalently bonded to another atom but the electrons in the outermost shell of the atom do not form an octet. Examples of electron-deficient atoms include atoms belonging to Group 13 of the periodic table, and more specifically, may be at least one of aluminum and boron, or may be boron.

[0046] 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 formed by replacing —O— of an ether compound with —NR Ｅ - (where R Ｅ is a hydrogen atom or an organic group). The azaether moiety may be either a linear azaether moiety or a cyclic azaether moiety, or may have both a linear azaether moiety and a cyclic azaether moiety. The group having an azaether moiety may have an electron-withdrawing group, for example, in the hydrocarbon moiety.

[0047] The structural unit (B) may contain at least one structural unit represented by the following formula (B): １１ ~R １３ The structure excluding W is also simply called an ethylene unit. (In formula (B), W is a functional group having a function as an anion receptor, and R １１ ~R １３ are each independently a hydrogen atom or a monovalent substituent, or R １１ and R １３ One of them is R １２ and form a ring together, and the other is a hydrogen atom or a monovalent substituent. * indicates the position where the structural unit (B) is bonded to another structural unit. R １１ ~R １３ may be hydrogen atoms, or all of may be hydrogen atoms.)

[0048] In formula (B), R １１ ~R １３ is a monovalent substituent, the monovalent substituent may be a monovalent organic group. The number of carbon atoms in the organic group may be, for example, 1 to 20, 1 to 15, 1 to 10, 1 to 5, or 1 to 3.

[0049] In formula (B), R １１ ~R １３is a monovalent substituent, the monovalent substituent may have an electron-withdrawing group or 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 the electron-withdrawing group include a halogen atom, a sulfonic acid group or a salt thereof, a sulfonic acid ester, a nitro group, and a nitrile group. The halogen atom may be a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

[0050] In formula (B), R １１ and R １３ One of them is R １２ When R forms a ring together with １１ or R １２ and R １３ form divalent substituents bonded to two carbon atoms of the ethylene unit of formula (B), respectively. These rings may be either carbocyclic or heterocyclic. The number of ring members of these rings may be, for example, 4 to 10, 5 to 8, 5, or 6. A substituent may be bonded to the carbon atom or heteroatom that is a ring member.

[0051] W in formula (B) preferably has a group represented by the following formula (B1). (In formula (B1), W Ｂ is an atom belonging to group 13 of the periodic table, and R １５ is a covalent bond or a divalent organic group, and R １６ and R １７ are each independently a hydrogen atom, an —OH group, a halogen atom, or a monovalent organic group, or are joined together to form a ring. １６ and R １７ may be the same group or different groups.)

[0052] W in formula (B1) Ｂ may be at least one of an aluminum atom and a boron atom, and may be a boron atom.

[0053] R in formula (B1) １５ When R is a divalent organic group, the number of carbon atoms in the divalent organic group may be, for example, 1 to 20, 1 to 15, 1 to 10, 1 to 5, or 1 to 3.１５ When is a divalent organic group, the organic group may be, for example, a hydrocarbon group, a halogen-substituted hydrocarbon group, or a hydrocarbon group or a halogen-substituted hydrocarbon group connected to W via an ether bond. Ｂ The halogen-substituted hydrocarbon group may be a hydrocarbon group in which some or all of the hydrogen atoms have been substituted with halogen atoms, and may be a partially fluorinated hydrocarbon group or a fully fluorinated hydrocarbon group. １５ may be a covalent bond.

[0054] R in formula (B1) １６ or R １７ is a halogen atom, R １６ or R １７ R may be any of a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and may also be a fluorine atom. １６ or R １７ may be the same or different.

[0055] R in formula (B1) １６ or R １７ When R is a monovalent organic group, the number of carbon atoms in the monovalent organic group may be, for example, 1 to 20, 1 to 15, 1 to 10, 1 to 5, or 1 to 3. １６ or R １７ is, for example, a hydrocarbon group, a halogen-substituted hydrocarbon group, or a hydrocarbon group or a halogen-substituted hydrocarbon group connected to W via an ether bond. Ｂ The halogen-substituted hydrocarbon group may be a hydrocarbon group in which some or all of the hydrogen atoms have been substituted with halogen atoms, and may be a partially fluorinated hydrocarbon group or a fully fluorinated hydrocarbon group.

[0056] The group represented by formula (B1) may be a group represented by formula (B1a) below or a group represented by formula (B1b) below. (In formula (B1a), R １５ is a covalent bond or a divalent organic group, W Ｂ is an atom belonging to group 13 of the periodic table, and X １１ and X １２ are each independently an oxygen atom or a covalent bond.１１ is a covalent bond, R ２２ is a hydrogen atom, a halogen atom, or a monovalent organic group. １１ is an oxygen atom, R ２２ is a hydrogen atom or a monovalent organic group. １２ is a covalent bond, R ２３ is a hydrogen atom, a halogen atom, or a monovalent organic group. １２ is an oxygen atom, R ２３ is a hydrogen atom, a halogen atom, or a monovalent organic group. １１ and X １２ When each is an oxygen atom, they may be oxygen atoms that form an ether bond. (In formula (B1b), R １５ is a covalent bond or a divalent organic group, W Ｂ is an atom belonging to group 13 of the periodic table, and X １３ and X １４ are each an oxygen atom or a covalent bond, and R ２４ is a divalent organic group.

[0057] In formula (B1a), R ２２ Or R ２３ When R is a monovalent organic group, the monovalent organic group may be a monovalent hydrocarbon group or a monovalent halogen-substituted hydrocarbon group. The number of carbon atoms in the monovalent organic group may be, for example, 1 to 20, 1 to 15, 1 to 10, 1 to 5, or 1 to 3. The halogen-substituted hydrocarbon group may be a hydrocarbon group in which some or all of the hydrogen atoms have been substituted with halogen atoms, and may be a partially fluorinated hydrocarbon group or a fully fluorinated hydrocarbon group. ２２ Or R ２３ When is a halogen atom, the halogen atom may be a fluorine atom.

[0058] R in formula (B1a) ２２ and R ２３ are each independently —F, —CH ３ , -C ２ H ５ , -C ３ H ７ , -C ６ H ５(phenyl group), —C ６ H ｎ F ５－ｎ (n is an integer of 0 to 4, and may be an integer of 0 to 3), -CF ３ , -CH ２ CF ３ , -CH ２ CF ３ CF ７ , -CH(CF ３ ) ２ , -C(CF ３ ) ２ -C ６ H ５ , -C(CF ３ ) ３ , and -C ６ H ｎ (CF ３ ) ５－ｎ (n is an integer from 0 to 4, and may be 1 or 2).

[0059] In formula (B1b), R ２４ is a divalent organic group, and the number of carbon atoms in the divalent organic group may be, for example, 1 to 20, 1 to 15, 2 to 10, or 3 to 8. The divalent organic group may be a hydrocarbon group or a halogen-substituted hydrocarbon group. The halogen-substituted hydrocarbon group may be a hydrocarbon group in which some or all of the hydrogen atoms have been substituted with halogen atoms, and may be a partially fluorinated hydrocarbon group or a fully fluorinated hydrocarbon group.

[0060] R in formula (B1b) ２４ For example, -C ２ H ４ -, -C ３ H ６ -, -C ４ H ８ -, -C ５ H １０ -, -C ６ H １２ -, -C ７ H １４ -, -C ８ H １６ -, -C ９ H １８ -, -C １０ H ２０-, etc., in which the hydrogen atoms are partially or entirely substituted with fluorine atoms. ２４ More specifically, -C(CH ３ ) ２ -C(CH ３ ) ２ - may be.

[0061] The polymer (A) may have a structural unit (C) that is not one of the structural units (A), (A'), and (B). The structural unit (C) may contain a structural unit represented by the following formula (C): (In formula (C), R ２５ is a hydrogen atom or a monovalent substituent, and R ２６ ~R ２８ are each independently a hydrogen atom or a monovalent substituent, or R ２６ and R ２７ is a hydrogen atom or a monovalent substituent, and the other is R ２８ and form a ring. * indicates the bonding site of the structural unit (C) to other structural units.

[0062] In formula (C), R ２５ may be a monovalent organic group. ２５ The number of carbon atoms contained in may be, for example, 1 to 40, 1 to 20, 2 to 15, or 4 to 13. １ -R ２９ In this case, Z may be a group represented by １ is a divalent linking group, for example, a covalent bond, —O—, —S—, —C(═O)—, —C(═O)O—, —OC(═O)—, or —C(═O)NR ３８ - or -NR ３９ It may be a group represented by C(=O)-.

[0063] The divalent linking group Z １ is a covalent bond, —O—, —S—, —C(═O)—, —C(═O)O—, or —OC(═O)—, R ２９ is a hydrogen atom or a monovalent organic group.

[0064] The divalent linking group Z １ is -C(=O)NR ３８-, then R ２９ , R ３８ are each a hydrogen atom or a monovalent organic group, or R ２９ is R ３８ Together with Z it forms a ring. １ But, -NR ３９ When C(=O)-, R ２９ , R ３９ are each a hydrogen atom or a monovalent organic group, or R ２９ is R ３９ It forms a ring together with R. ２９ , R ３８ and R ３９ The number of carbon atoms in the monovalent organic group as R may be 1 to 20, or 1 to 10. ３８ When is a monovalent organic group, it may be a monovalent hydrocarbon group having 1 to 20 carbon atoms.

[0065] The divalent linking group Z １ is a covalent bond or —C(═O)O—, R ２９ may be a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. １ is a covalent bond and R ２９ When R is a hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. ２９ may be a monovalent organic group other than a hydrocarbon group or a hydrocarbon group having a ring structure.

[0066] The divalent linking group Z １ When is —O—, W ０ as alkyl ethers, ０ The monovalent organic group may be a monovalent organic group other than the group represented by —H. ２６ ~R ２８ When R is a monovalent organic group, the monovalent organic group is ２５ The same examples as those given above are included.

[0067] In a group having an aromatic ring (for example, the above-mentioned aromatic hydrocarbon group), a monovalent substituent may be bonded to the aromatic ring. Examples of the monovalent substituent include a monovalent organic group, and examples of the monovalent organic group include a substituted or unsubstituted hydrocarbon group, a group represented by the formula: -R ６１ - (W １ -R ６２ ) ｎ -W ２ R ６３ and the like.

[0068] Formula:-R ６１ - (W １ -R ６２ ) ｎ -W ２ R ６３ The group represented by the formula (I) may be bonded to the para position of the benzene ring. １ may be a divalent group such as -O-, -S-, -C(=O)-, or -C(=O)O-, or may be -O-. ２ may be a divalent group such as —O—, —S—, —C(═O)—, or —C(═O)O—, or may be —O—.

[0069] R in the monovalent organic group ６１ is a covalent bond or a divalent organic group. The divalent organic group may be a divalent hydrocarbon group. The divalent hydrocarbon group may have, for example, 1 to 8, 1 to 5, or 1 to 3 carbon atoms. The hydrogen atoms bonded to the divalent hydrocarbon group may be substituted with a substituent such as a monovalent substituent (i.e., the divalent hydrocarbon group may be a substituted hydrocarbon group). Examples of the substituent include a halogen atom such as a fluorine atom. Specific examples of the divalent hydrocarbon group include a methylene group, an ethylene group, a 1,2-propylene group, a 1,3-propylene group, or a group in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine atoms, and may be a methylene group.

[0070] R in the monovalent organic group ６２is a divalent organic group and may be a divalent hydrocarbon group. The divalent hydrocarbon group may have, for example, 1 to 8, 1 to 5, or 1 to 3 carbon atoms. The hydrogen atoms bonded to the divalent hydrocarbon group may be substituted with a substituent such as a monovalent substituent (i.e., the divalent hydrocarbon group may be a substituted hydrocarbon group). Examples of such substituents include halogen atoms such as fluorine atoms. The divalent hydrocarbon group may be a methylene group, an ethylene group, a 1,2-propylene group, a 1,3-propylene group, or a group in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine atoms, or may be an ethylene group.

[0071] The above formula: -R ６１ - (W １ -R ６２ ) ｎ -W ２ R ６３ In the group represented by the formula (I), n may be, for example, 1 to 10, 1 to 5, or 1 to 3. The n may be an integer or a rational number (for example, n may be an average value across the structural units (B) contained in the polymer). ６２ When there are multiple, they may be different or the same.

[0072] R in the monovalent organic group ６３ may be a hydrogen atom or a monovalent hydrocarbon group. The number of carbon atoms in the monovalent hydrocarbon group may be, for example, 1 to 8, 1 to 5, or 1 to 3. The hydrogen atoms bonded to the monovalent hydrocarbon group may be substituted with a substituent such as a monovalent substituent (i.e., the monovalent hydrocarbon group may be a substituted hydrocarbon group). Examples of the substituent include a halogen atom such as a fluorine atom. The monovalent hydrocarbon group may be a methyl group, an ethyl group, an isopropyl group, an n-propyl group, or a group in which some or all of the hydrogen atoms in these groups have been substituted with halogen atoms such as fluorine atoms, or may be a methyl group.

[0073] When the polymer (A) has the structural unit (C), the structural unit (C) may include a structural unit derived from a monomer represented by the following formula (C1). (In formula (C1), m is 0 to 4, and n is 0 to 10. R ３１ may be a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. The alkyl group may be a methyl group or an ethyl group, and may be a methyl group.

[0074] In formula (C1), m may be, for example, 1 to 3, 1 to 2, or 1. m may be an integer or an average value across all structural units derived from the monomer represented by formula (C1) contained in the polymer (in this case, m is a rational number). In formula (C1), n ​​may be, for example, 1 to 4, or 1 to 3. n may be an integer or an average value across all structural units derived from the monomer represented by formula (C1) contained in the polymer (in this case, n is a rational number).

[0075] When the polymer (A) has the structural unit (C), R ２６ and R ２７ One of them is R ２８ When R forms a ring together with the structural unit (C), the ring may have, for example, 4 to 10 members, 4 to 8 members, or 5 to 7 members. ２７ is R ２８ When the structural unit (C) is taken together with the structural unit (C) to form a ring, the structural unit (C) may be the following structural unit (C2). (In formula (C2), X represents an oxygen atom or —NR ３１ - is a tertiary amino group represented by R ３１ is a monovalent organic group, and R ２５ and R ２６ are each independently a hydrogen atom or a monovalent substituent.

[0076] In formula (C2), X is -NR ３１ When the tertiary amino group is represented by -, R ３１ The number of carbon atoms contained in the R may be, for example, 1 to 20, 1 to 15, or 2 to 10. ３１ may be a hydrocarbon group or a hydrocarbon group substituted with fluorine, and may be an ethyl group, a 2,2,2-trifluoroethyl group, an n-dodecyl group, a cyclohexyl group, or a benzyl group.

[0077] The ratio of the structural unit (A) to all structural units contained in the polymer (A) may be 0.2 to 0.95, 0.2 to 0.8, 0.3 to 0.7, or 0.4 to 0.6.

[0078] The ratio of the structural unit (C) to all structural units contained in the polymer (A) may be, for example, 0.05 to 0.8, 0.2 to 0.8, 0.3 to 0.7, or 0.4 to 0.6. The ratio of the structural unit (C) to all structural units contained in the polymer (A) may be 0.8 or less, 0.7 or less, 0.6 or less, 0.5 or less, 0.4 or less, or 0.3 or less.

[0079] The total proportion of the structural units (A) and (C) relative to all structural units contained in the polymer (A) may be, for example, 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.

[0080] The content of the structural unit (A) relative to the total mass of the polymer (A) may be, for example, 25 to 95 mass %, 40 to 90 mass %, or 50 to 90 mass %.

[0081] The content of the structural unit (C) relative to the total mass of the polymer (A) may be, for example, 5 to 75 mass%, 10 to 60 mass%, or 10 to 50 mass%, and the content of the structural unit (C) relative to the total mass of the polymer (A) may be, for example, 75 mass% or less, 60 mass% or less, 50 mass% or less, or 25 mass% or less.

[0082] The total content of the structural unit (A) and the structural unit (C) relative to the total mass of the polymer (A) may be, for example, 90 mass % or more, 95 mass % or more, or 98 mass % or more.

[0083] When the polymer (A) contains the structural unit (B), the molar ratio m of the structural unit (B) to all structural units contained in the polymer (A) may be, for example, 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.

[0084] The content of the structural unit (B) relative to the total mass of the polymer (A) may be, for example, more than 10% by mass and not more than 95% by mass, 15 to 95% by mass, 20 to 80% by mass, 25 to 60% by mass, or 30 to 45% by mass.

[0085] The number average molecular weight (Mn) of the polymer (A) may be, for example, 5,000 to 400,000, 8,000 to 200,000, 10,000 to 150,000, or 10,000 to 100,000. The weight average molecular weight (Mw) of the polymer (A) may be, for example, 5,000 to 600,000, 10,000 to 450,000, 20,000 to 200,000, or 20,000 to 100,000. The molecular weight distribution (Mw / Mn) of the polymer (A) may be, for example, 1.0 to 5.0, 1.2 to 3.0, or 1.3 to 2.5.

[0086] The number average molecular weight and weight average molecular weight of the polymer (A) in this specification can be measured by gel permeation chromatography (GPC) performed under the following conditions. For preparing a calibration curve, a standard sample of polymethyl methacrylate (manufactured by Polymer Laboratories, Mn 800 to 2,200,000) is used as the standard substance. <GPC measurement conditions> Apparatus: High-performance liquid chromatograph PU-2080 precision pump RI-2031 refractive-index detector UV-2075 UV / vis detector, manufactured by JASCO Corporation Column: Shodex KF-805L (exclusion limit: 4 × 10 ６ , particle size: 10 μm, pore size: 5000 Å, inner diameter: 0.8 cm, length: 30 cm) Temperature: 40° C. Solvent: dimethylformamide (DMF) Flow rate: 1.0 mL / min Back pressure: 3.0 MPa Detection: RI Sample concentration: 0.5 mass % DMF solution Injection volume: 10 μL

[0087] The content of the polymer (A) in the electrolyte composition according to this embodiment may be, for example, 1 to 80 mass%, 3 to 70 mass%, 5 to 60 mass%, or 10 to 40 mass%, relative to the total amount of the electrolyte composition.

[0088] The method for producing the polymer (A) and the polymer (B) is not particularly limited, but for example, they can be produced by subjecting the corresponding monomers to a polymerization reaction such as radical addition polymerization.

[0089] <Particles> The particles contained in the electrolyte composition according to this embodiment are not particularly limited and may be either inorganic particles or organic particles. The particles may be non-conductive particles. The material of the particles is preferably one that has the following conductivity measured at 25°C, for example, 1.0 × 10 －６ Sm －１ Below, 1.0 x 10 －７ Sm －１ or less, or 1.0 x 10 －１０ Sm －１ It may be the following:

[0090] Examples of inorganic particles include oxide particles, nitride particles, carbide particles, carbon particles, sulfur particles, and silicate mineral particles. Examples of oxide particles include silicon oxide particles (silica particles), aluminum oxide particles (alumina particles), and titanium oxide particles (titania particles). Examples of nitride particles include boron nitride particles and aluminum nitride particles. Examples of carbide particles include silicon carbide particles. Examples of silicate mineral particles include mica. Examples of organic particles include acrylic particles and melamine particles.

[0091] The particles may be nanoparticles. The average particle size of the particles may be, for example, 500 nm or less, 300 nm or less, 200 nm or less, 150 nm or less, 100 nm or less, or 80 nm or less, or 1 nm or more, 3 nm or more, or 5 nm or more. The average particle size of the particles may be 1 to 500 nm, 1 to 300 nm, 3 to 200 nm, 3 to 150 nm, 5 to 100 nm, 5 to 80 nm, or 5 to 50 nm or less.

[0092] The average particle size of particles in this specification means the particle size (D50) when the cumulative value from the small particle size reaches 50% in the volume-based particle size distribution measured by a laser diffraction particle size distribution analyzer. Examples of the laser diffraction particle size distribution analyzer that can be used include "SALD2200" (trade name) and "SALD2300" (trade name) manufactured by Shimadzu Corporation.

[0093] The maximum particle size of the primary particles of the above particles may be, for example, 500 nm or less, 300 nm or less, 200 nm or less, 150 nm or less, 100 nm or less, or 80 nm or less, or may be 1 nm or more, 3 nm or more, or 5 nm or more.

[0094] The maximum value of the primary particle diameter (maximum particle diameter) of the particles can be determined by analyzing an image acquired by a scanning electron microscope or a transmission electron microscope. More specifically, from the image acquired by the scanning electron microscope or the transmission electron microscope, 100 particles that are judged to be large visually are selected from the primary particles of the particles to be measured, and the particle diameters of the selected particles are measured, and the maximum value is defined as the maximum particle diameter.

[0095] The content of the particles in the electrolyte composition may be, for example, 50% by mass or less, 40% by mass or less, 35% by mass or less, or 30% by mass or less, or 0.1% by mass or more, 1% by mass or more, 5% by mass or more, 10% by mass or more, or 15% by mass or more, relative to the total amount of the electrolyte composition. The content of the particles in the electrolyte composition may be 0.1 to 50% by mass, 1 to 40% by mass, 5 to 35% by mass, 10 to 30% by mass, or 15 to 25% by mass, relative to the total amount of the electrolyte composition.

[0096] <Organic Solvent> Examples of the organic solvent include aprotic solvents. The organic solvent may include one or more solvents selected from the group consisting of carbonate-based solvents, ether-based solvents, fluorine-based solvents, nitrile-based solvents, phosphate ester-based solvents, and sulfone-based solvents, and may include a carbonate-based solvent. In the electrolyte composition, the polymer (A) may be swollen by the organic solvent.

[0097] Examples of carbonate solvents include chain 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. The organic solvent may be a mixed solvent containing two or more carbonate solvents, such as a mixed solvent containing one or more cyclic carbonate solvents and one or more chain carbonate solvents, or a mixed solvent containing two or more cyclic carbonate solvents.

[0098] Examples of ether solvents include cyclic ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, and 1,3-dioxolane; and chain ethers such as 1,2-diethoxyethane and ethoxymethoxyethane.

[0099] Examples of fluorine-based solvents include hydrofluorocarbons such as perfluorooctane; hydrofluoroethers such as methyl nonafluorobutyl ether and ethyl nonafluorobutyl ether; hydrofluoroolefins such as 1,3,3,3-tetrafluoropropene; and 2,2,2-trifluoro-N,N-dimethylacetamide.

[0100] Examples of the nitrile solvent include acetonitrile, succinonitrile, etc. Examples of the lactone solvent include γ-butyrolactone, etc.

[0101] Examples of phosphate ester solvents include trimethyl phosphate (TMP), triethyl phosphate (TEP), and tris(2,2,2-trifluoroethyl) phosphate (TFEP).

[0102] Examples of sulfonic acid solvents include sulfolane and 3-methylsulfolane.

[0103] In addition to the above-mentioned solvents, examples of the organic solvent include solvents having a sulfonyl group such as dimethyl sulfoxide (DMSO); amide solvents such as dimethylformamide (DMF) and dimethylacetamide (DMA); organic solvents having a carbonyl group such as acetone (referring to carbonyl compounds other than amide compounds such as -C(=O)-, esters, ketones, and aldehydes); and nitrogen-containing aromatic compounds such as pyridine (compounds containing nitrogen as a ring member of the aromatic ring, which may be either monocyclic or fused ring systems). The organic solvent may be used alone or as a mixed solvent containing two or more organic solvents.

[0104] The content of the organic solvent in the electrolyte composition may be, for example, 10 to 1000 parts by mass, 50 to 800 parts by mass, 100 to 600 parts by mass, 150 to 600 parts by mass, or 200 to 500 parts by mass relative to 100 parts by mass of the polymer contained in the electrolyte composition.

[0105] The transference number of the alkali metal ion in the electrolyte composition may be, for example, 0.5 or more, 0.6 or more, or 0.7 or more. The transference number is the transference number measured at room temperature (25° C.).

[0106] In addition to the components described above, the electrolyte composition according to this embodiment may further include, for example, other resins such as fluorine-based resins (binder resins, resins other than the polymer (A) and the polymer (B)), porous materials, alkali metal salts, coating-forming additives, fabrics such as nonwoven fabrics, viscosity modifiers, and anion receptors.

[0107] <Other Resins> The fluororesin may include a resin having a carbon chain as the main chain. The carbon chain may be formed by radical polymerization of an ethylenically unsaturated group. Examples of fluororesins include polytetrafluoroethylene (PTFE), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), and polyvinylidene fluoride (PVDF).

[0108] The content of the other resin in the electrolyte composition may be, for example, 0.1 to 20 mass%, 0.5 to 10 mass%, or 1 to 5 mass%, relative to the total amount of the electrolyte composition. The content of the other resin may be 10 to 200 mass parts, or 50 to 150 mass parts, relative to 100 mass parts of the polymer (A).

[0109] <Porous Material> The porous material may be a resin porous material. Specific examples of the porous material include a porous polyolefin membrane and a porous ceramic membrane.

[0110] <Alkali Metal Salt> Examples of alkali metal salts include MF, MCl, MBr, MI, and MNO, where M is an alkali metal. ３ , MClO ４ , MPF ６ , MBF ４ , M ２ SO ４ , M[(C ｈ F ２ｈ＋１ ) SO ３ ] (h is 0 to 3), M[(C ｈ F ２ｈ＋１ ) SO ２ ] ２ N (h is 0 to 3), M{[(C ｈ F ２ｈ＋１ ) SO ２ ]N[(C ｉ F ２ｉ＋１ ) SO ２ ]} (h and i are 0 to 3), and MBOB (BOB is bisoxalatoborate). The alkali metal salts may be used alone or in combination of two or more. The alkali metal M is not particularly limited as long as it is an element classified as an alkali metal, and may contain, for example, lithium, sodium, or potassium, or may contain lithium or sodium, or may contain lithium. The alkali metal element contained in the alkali metal salt may be the same alkali metal element as the alkali metal element contained in the structural unit (A) and the structural unit (A').

[0111] The content of the alkali metal salt in the electrolyte composition may be, for example, 0.1 to 200 mol %, 2.5 to 150 mol %, 5 to 100 mol %, or 10 to 60 mol % in terms of the alkali metal ions contained in the alkali metal salt, relative to the total amount of structural units (A) contained in the polymer (A).

[0112] <Film-forming additive> The film-forming additive is a compound that can form a film (solid electrolyte interface, SEI) on the electrode surface by an electrolytic reaction. Therefore, the film-forming additive may be an SEI-forming agent. The film-forming additive may be at least one of an electrolytic oxidation-polymerizable compound and an electrolytic reduction-polymerizable compound, but may also be an electrolytic reduction-polymerizable compound. By using an electrolytic reduction-polymerizable compound, a film can be formed on the negative electrode.

[0113] The content of the film-forming additive in the electrolyte composition may be, for example, 0.01 to 100 parts by mass, 0.1 to 80 parts by mass, 1 to 50 parts by mass, 1 to 30 parts by mass, 3 to 25 parts by mass, or 5 to 20 parts by mass relative to 100 parts by mass of the polymer (A).

[0114] The method for producing the electrolyte composition is not particularly limited, but it can be obtained by mixing a polymer, an organic solvent, and particles. At this time, an alkali metal salt or a film-forming additive may be added. The electrolyte composition may be formed into a film or pellets and used as a molded body.

[0115] The electrolyte composition of this embodiment can be used, for example, as a composition for forming an electrolyte in an electrode composition, a battery, a capacitor, or the like. That is, one embodiment of the electrode composition has an electrolyte, and the electrolyte may include the above-described electrolyte composition. Furthermore, one embodiment of the battery and capacitor has an electrolyte, and the electrolyte may include the above-described electrolyte composition. Examples of the battery include batteries that charge and discharge by the movement of alkali metal ions, such as lithium ion batteries and sodium ion batteries. The battery may be a primary battery, a secondary battery, or a solid-state battery. The electrolyte composition of this embodiment may be used as an electrode composition or may be contained in at least one of a positive electrode and a negative electrode. That is, the above-described electrolyte composition is suitable as an electrode mixture. An electrode made of the electrode composition can have excellent ionic conductivity within the electrode.

[0116] (Battery) The battery of this embodiment includes a positive electrode, a negative electrode, and an electrolyte disposed between the positive electrode and the negative electrode. The electrolyte may be formed by disposing the electrolyte composition of this embodiment between the positive electrode and the negative electrode. The battery may also include an electrolyte (such as a solid electrolyte layer) other than the electrolyte formed from the electrolyte composition of this embodiment. The positive electrode may be formed by forming a layer containing a positive electrode material on a current collector. The negative electrode may be formed by forming a layer containing a negative electrode material on a current collector. When the electrolyte composition includes an organic solvent, an interface can be more easily formed between the electrodes (positive electrode and negative electrode) and the electrolyte. In other words, the electrolyte composition may include an organic solvent to form an interface between at least one of the positive electrode and the electrolyte, and the negative electrode and the electrolyte. The organic solvent may be added to the electrolyte composition when the battery is assembled, or the organic solvent may be added between the electrodes and the electrolyte composition when the electrolyte composition is disposed between the electrodes. Below, the battery of this embodiment will be described using a lithium-ion battery as an example.

[0117] The negative electrode of the lithium ion battery is not particularly limited, and may contain a negative electrode active material and, if necessary, a conductive additive, a binder, etc. Examples of the negative electrode active material include simple elements such as Li, Si, P, Sn, Si—Mn, Si—Co, Si—Ni, In, and Au, alloys or composites containing these elements, carbon materials such as graphite, substances in which lithium ions are inserted between the layers of the carbon material, and oxides containing titanium.

[0118] The positive electrode of the lithium ion battery is not particularly limited, and may contain a positive electrode active material and, if necessary, a conductive additive, a binder, etc. The positive electrode active material is not particularly limited, and examples thereof include lithium composite metal oxides containing lithium and a transition metal element. The transition metal element may be at least one selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, Cu, and Al, and may contain Ni. Examples of lithium composite metal oxides include LiCoO ２ , LiNiO ２ , LiMn ２ O ４ , LiNi ０．５ Mn １．５ O ４ , Li ２ MnO ３ , LiNi ｘ Mn ｙ Co １－ｘ－ｙ O ２ [0<x+y<1]), LiNi ｘ Co ｙ Al １－ｘ－ｙ O ２ [0<x+y<1]), LiCr ０．５ Mn ０．５ O ２ , LiFePO ４ , Li ２ FeP ２ O ７ , LiMnPO ４ , LiFeBO ３ , Li ３ V ２ (P.O. ４ ) ３ , Li ２ CuO ２ , Li ２ FeSiO４ , and Li ２ MnSiO ４ When the positive electrode active material contains an alkali metal element other than Li, specific examples thereof include those in which Li in the above specific examples is replaced with another alkali metal.

[0119] The negative electrode (negative electrode material) and the positive electrode (positive electrode material) in this embodiment may further contain a solid electrolyte material, a binding resin (binder), a conductive assistant, and the like.

[0120] The battery according to this embodiment may include a separator. The separator may be a porous material, such as a porous resin material. Specific examples of the porous material include a porous polyolefin membrane and a porous ceramic membrane.

[0121] The present disclosure will be described in more detail below using examples and comparative examples, but the present disclosure is not limited to the following examples.

[0122] <Synthesis of Monomer X> Monomer X represented by the following formula was synthesized by the following method.

[0123]

[0124] First, chlorosulfonic acid (69 mL, 1.04 mol) was added to N-phenylmaleimide (30 g, 0.17 mol) at 0°C, and the mixture was stirred at 45 to 50°C for 1 hour. The resulting product was cooled to room temperature and poured onto ice. After stirring for a while, the precipitated crystals were collected by filtration and purified by silica gel column chromatography. The eluent used was a mixture of hexane and ethyl acetate in a volume ratio of 2 / 1 to 1 / 1. As a result of purification, 34 g (yield 73%) of an intermediate represented by the following formula was obtained. The resulting intermediate was a pale yellow solid.

[0125]

[0126] Next, under a nitrogen atmosphere, trifluoromethanesulfonamide (manufactured by Tokyo Chemical Industry Co., Ltd.) (4.22 g, 28.3 mmol) was dissolved in dehydrated acetonitrile (160 mL, manufactured by Kanto Chemical Co., Ltd.) to prepare a solution. To this solution, 1.0 equivalent of lithium carbonate relative to trifluoromethanesulfonamide, 2.0 equivalents of lithium hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd.), and the intermediate synthesized as described above (6.9 g, 25.5 mmol) were added in that order, and the reaction was carried out at 0°C for 4.5 hours. After the temperature of the reaction solution was returned to room temperature, it was filtered, and the solvent was distilled off from the filtrate under reduced pressure. The residue was decanted with diethyl ether and dried under reduced pressure, yielding 10.5 g of monomer X as a pale brown solid.

[0127] <Synthesis of Copolymer> 0.558 g of the monomer X obtained as described above, 0.149 g of styrene, and 11.7 mg of azobisisobutyronitrile were dissolved in 6.7 mL of dehydrated acetonitrile, and the mixture was reacted at 60°C for 24 hours under a nitrogen atmosphere while adding tetralin as an internal standard substance to check the monomer consumption rate. The polymerization solution was dialyzed in acetonitrile and vacuum dried at 120°C to obtain 0.640 g of copolymer (yield 87%). The monomer introduction ratio was monomer X:styrene = 52:48. １ The number average molecular weight of the copolymer was calculated from H-NMR. Mn = 9.4 × 10 ４ , weight average molecular weight Mw=4.2×10 ５ The number average molecular weight and the weight average molecular weight were measured by gel permeation chromatography.

[0128] Example 1 [Production of Electrolyte Composition] A resin mixture of 100 parts by mass of the above copolymer and 50 parts by mass of PVdF-HFP (poly(vinylidene fluoride-co-hexafluoropropylene)) was mixed with 450 parts by mass of an organic solvent to prepare a gel-like polymer composition 1 (gel polymer 1).

[0129] An electrolyte composition was obtained by weighing and mixing 80 parts by mass of the gel polymer 1 prepared as described above, 20 parts by mass of fumed silica (average particle size: 7 nm), and 3 parts by mass of polytetrafluoroethylene (PTFE) in a mortar. The organic solvent used was obtained by mixing a mixed solvent of ethylene carbonate (EC) and propylene carbonate (PC) (volume ratio 1:1) with fluoroethylene carbonate (FEC) in a mass ratio of 95:5.

[0130] Example 2 An electrolyte composition was obtained in the same manner as in Example 1, except that alumina A (average particle size: 13 nm) was used instead of fumed silica.

[0131] Example 3 An electrolyte composition was obtained in the same manner as in Example 1, except that alumina B (average particle size: 10 nm) was used instead of fumed silica.

[0132] Example 4 A resin obtained by mixing 100 parts by mass of the copolymer and 50 parts by mass of PVdF-HFP was mixed with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in an amount of 25 mol % relative to 100 mol % of the structural unit (A) of the copolymer, and 450 parts by mass of an organic solvent, to prepare a gel-like polymer composition 2 (gel polymer 2).

[0133] An electrolyte composition was obtained by weighing and mixing 80 parts by mass of the gel polymer 2 prepared as described above, 20 parts by mass of fumed silica (average particle size: 7 nm), and 3 parts by mass of polytetrafluoroethylene (PTFE) in a mortar. The organic solvent used was obtained by mixing a mixed solvent of ethylene carbonate (EC) and propylene carbonate (PC) (volume ratio 1:1) with fluoroethylene carbonate (FEC) in a mass ratio of 95:5.

[0134] Example 5 A resin obtained by mixing 100 parts by mass of the copolymer and 50 parts by mass of PVdF-HFP was mixed with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in an amount of 25 mol % relative to 100 mol % of the structural unit (A) of the copolymer, and 600 parts by mass of an organic solvent, to prepare a gel-like polymer composition 3 (gel polymer 3).

[0135] An electrolyte composition was obtained by weighing and mixing 80 parts by mass of the gel polymer 3 prepared as described above, 20 parts by mass of fumed silica (average particle size: 7 nm), and 3 parts by mass of polytetrafluoroethylene (PTFE) in a mortar. The organic solvent used was obtained by mixing a mixed solvent of ethylene carbonate (EC) and propylene carbonate (PC) (volume ratio 1:1) with fluoroethylene carbonate (FEC) in a mass ratio of 95:5.

[0136] Example 6 A resin obtained by mixing 100 parts by mass of the copolymer and 50 parts by mass of PVdF-HFP was mixed with lithium bis(trifluoromethanesulfonylimide) (LiTFSI) in an amount of 50 mol % relative to 100 mol % of the structural unit (A) of the copolymer, and 450 parts by mass of an organic solvent to prepare a gel-like polymer composition 4 (gel polymer 4).

[0137] An electrolyte composition was obtained by weighing and mixing 80 parts by mass of gel polymer 4, 20 parts by mass of fumed silica (average particle size: 7 nm), and 3 parts by mass of polytetrafluoroethylene (PTFE) in a mortar. The organic solvent used was obtained by mixing a mixed solvent of ethylene carbonate (EC) and propylene carbonate (PC) (volume ratio 1:1) with fluoroethylene carbonate (FEC) in a mass ratio of 95:5.

[0138] Example 7 100 parts by mass of the copolymer described above and 300 parts by mass of an organic solvent were mixed to prepare a gel-like polymer composition 5 (gel polymer 5).

[0139] An electrolyte composition was obtained by weighing and mixing 80 parts by mass of the gel polymer 5 prepared as described above, 20 parts by mass of fumed silica (average particle size: 7 nm), and 3 parts by mass of polytetrafluoroethylene (PTFE) in a mortar. The organic solvent used was obtained by mixing a mixed solvent of ethylene carbonate (EC) and propylene carbonate (PC) (volume ratio 1:1) with fluoroethylene carbonate (FEC) in a mass ratio of 95:5.

[0140] Comparative Example 1 The gel polymer 1 prepared in Example 1 was used as the electrolyte composition of Comparative Example 1 without any modification.

[0141] Comparative Example 2 The gel polymer 4 produced in Example 6 was used as the electrolyte composition of Comparative Example 2 without any modification.

[0142] Comparative Example 3 The gel polymer 5 produced in Example 5 was used as the electrolyte composition of Comparative Example 3 without any modification.

[0143] <Measurement of Maximum DC Current Density> An evaluation cell of the coin-type battery CR2032 was assembled in a glove box under a dry argon atmosphere. Specifically, first, each layer was laminated in the order of lithium / electrolyte composition / lithium in evaluation cell A to prepare a test laminate.

[0144] The evaluation cell was alternately energized in the positive and negative directions at 0.2 mA / cm ２ , 0.4mA / cm ２ , 0.8mA / cm ２ , 1.2mA / cm ２ , 1.6mA / cm ２ , 2.0mA / cm ２ , 2.4mA / cm ２ , 2.8mA / cm ２ , 3.2mA / cm ２ , 3.6mA / cm ２ , 4.0mA / cm ２ , and 4.4 mA / cm ２ A constant current test was carried out in which current densities of 10 ...

[0145] <Measurement of ionic conductivity> An evaluation cell of coin-type battery CR2032 was assembled in a glove box under a dry argon atmosphere. Specifically, first, a test laminate was prepared by laminating each layer in the following order in evaluation cell B: stainless steel plate / electrolyte composition / stainless steel plate.

[0146] Measurements were made using an impedance measuring device under the conditions of 25°C, a frequency range of 0.1 Hz to 1 MHz, and an applied voltage of 10 mV (vs. open circuit voltage). The ionic conductivity σ was calculated using the following formula. In the formula, R represents the impedance value, A represents the area of ​​the sample, and t represents the thickness of the sample. The results are shown in Table 1. σ (S cm －１ )=t(cm) / (R(Ω)×A(cm ２ ))

[0147] <Measurement of Activation Energy> Ion conductivity measurements using the above-mentioned evaluation cell B were also carried out under conditions of 30°C, 40°C, 50°C, 60°C, and 70°C, and the change in ionic conductivity with respect to temperature was measured. The activation energy was calculated from the slope of a graph of the common logarithm of ionic conductivity versus 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.

[0148] <Measurement of DC Current Density> Using evaluation cell A of the coin-type battery CR2032 (a test laminate obtained by laminating the layers in the order of lithium / electrolyte composition / lithium), DC current density was measured in the same manner as in the method described in "Measurement of maximum DC current density."

[0149] <Measurement of Lithium Ion Transference Number> The lithium ion transference number was measured using evaluation cell A of the coin-type battery CR2032 (a test laminate obtained by laminating the layers in the order of lithium / electrolyte composition / lithium).

[0150] The lithium ion transport number was determined under the following conditions: At room temperature (25° C.), 10 mV was applied to the test laminate, and the initial current value (I ０ ) and steady-state current value (I ｓｓThe obtained value was then inserted into the following equation to determine the lithium ion transport number (t Ｌｉ＋ The results are shown in Table 1. Ｌｉ＋ =I ｓｓ / I ０

[0151]

[0152] (Lithium Dissolution and Precipitation Test) The following lithium dissolution and precipitation test was carried out on the evaluation cell A (a test laminate obtained by stacking the layers in the order of lithium / electrolyte composition / lithium) of the coin-type battery CR2032 prepared using each of the electrolyte compositions of Example 6 and Comparative Example 2.

[0153] That is, for the evaluation cell, +400 μA / cm ２ and -400 μA / cm ２ A test was conducted in which current was alternately passed at current densities of 1000 and 10000 for one hour each, which constituted one cycle, and this cycle was repeated for evaluation cell A. In each cycle, the voltage value immediately before the current was reversed from the positive direction to the negative direction was measured as the voltage value for that cycle. The relationship between the number of cycles and the voltage value for each cycle is shown in Figure 1. In Figure 1, the measurement results when the electrolyte composition of Example 6 was used are shown as "Fumed Silica Added", and the measurement results when the electrolyte composition of Comparative Example 2 was used are shown as "Fumed Silica Not Added".

[0154] The results shown in Table 1 confirm that by satisfying the requirements of the electrolyte composition according to the present disclosure, a larger current can be passed at a lower voltage than with an electrolyte composition that does not satisfy the requirements. For example, in the case of using the same gel polymer, it has been confirmed that an electrolyte composition containing particles exhibits superior performance compared to an electrolyte composition that does not contain particles.

Claims

1. An electrolyte composition comprising a polymer, an organic solvent, and particles, wherein the polymer has side groups containing one or more groups selected from the group consisting of an alkali metal substituted phenol group, an alkali metal substituted carboxylic acid group, an alkali metal substituted sulfonic acid group, and an alkali metal substituted sulfonylimide group.

2. The electrolyte composition of claim 1, wherein the particles are nanoparticles.

3. The electrolyte composition of claim 1 or 2, wherein the side groups comprise lithium ions or sodium ions.

4. The electrolyte composition according to claim 1 or 2, wherein the organic solvent comprises one or more solvents selected from the group consisting of carbonate-based solvents, ether-based solvents, fluorine-based solvents, nitrile-based solvents, lactone-based solvents, phosphate ester-based solvents, and sulfone-based solvents.

5. The electrolyte composition according to claim 1 or 2, wherein the side groups comprise one or more groups selected from the group consisting of lithiated phenol groups, lithiated carboxylic acid groups, lithiated sulfonic acid groups, and lithiated sulfonylimide groups.

6. The electrolyte composition according to claim 1 or 2, further comprising an alkali metal salt.

7. The electrolyte composition according to claim 1 or 2, which has a transport number of 0.5 or more.

8. The electrolyte composition according to claim 1 or 2, wherein the particles comprise at least one selected from the group consisting of carbon particles, sulfur particles, silicon oxide particles, aluminum oxide particles, titanium oxide particles, and organic particles.

9. The electrolyte composition according to claim 1 or 2, wherein the content of the particles is 50 mass % or less based on the total amount of the electrolyte composition.

10. An electrode composition comprising the electrolyte composition of claim 1 or 2.

11. A battery comprising the electrolyte composition of claim 1 or 2.

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