Electrolyte composition, electrode, and secondary battery

Abstract

The present disclosure provides an electrolyte composition containing a polymer, inorganic particles, and an organic solvent. When a specific surface area of the inorganic particles as measured by a multipoint BET method using N2 as an adsorption gas is defined as BET(N2) and a specific surface area of the inorganic particles as measured by a multipoint BET method using H2O as an adsorption gas is defined as BET(H2O), the ratio of the BET(H2O) with respect to the BET(N2) is not less than 0.30.

Description

Electrolyte composition, electrode, and secondary battery

[0001] This disclosure relates to an electrolyte composition, an electrode, and a secondary battery.

[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 used in lithium-ion batteries, research is progressing on solid electrolytes and polymer electrolytes from the standpoint of safety and processability (Patent Documents 1 or 2). Furthermore, research is also underway on batteries using other alkali ions, such as sodium and potassium, which are more abundant than lithium, in addition to lithium-ion batteries.

[0003] Korean Published Patent No. 10-2016-0050870, Japanese Patent Publication No. 2023-511906

[0004] To prevent lithium dendrite formation, inorganic particles are sometimes incorporated into polymer electrolytes to improve the mechanical strength of the electrolyte. Even among electrolyte compositions containing inorganic particles, those with superior ionic conductivity would be particularly useful.

[0005] The purpose of this disclosure is to provide an electrolyte composition with excellent ionic conductivity.

[0006] This disclosure provides the following [1] to

[11] .

[0007] [1] A polymer, inorganic particles, and an organic solvent, wherein the inorganic particles are N as an adsorbent gas. ２ The specific surface area measured by the BET multipoint method using BET(N) is expressed as BET(N) ２ ) and H as the adsorbent gas ２ The specific surface area measured by the BET multipoint method using O is BET(H ２ When O), the BET(N ２ ) the BET(H ２An electrolyte composition in which the ratio of (O) is 0.30 or more. [2] The electrolyte composition according to [1], wherein the inorganic particles contain at least one selected from the group consisting of silica particles, alumina particles, and titania particles. [3] The electrolyte composition according to [1] or [2], further containing metal ions. [4] The electrolyte composition according to [3], wherein the metal ions contain alkali metal ions. [5] The electrolyte composition according to any one of [1] to [4], wherein the polymer has an anionic group and an alkali metal ion as a counter cation of the anionic group. [6] The polymer is an alkali metalated phenol group, an alkali metalated carboxylic acid group (-CO ２ A), an alkali metalated sulfonic acid group (-SO ３ A), an alkali metalated carbonylsulfonylimide group (-SO ２ NACO-), and an alkali metalated sulfonylimide group (-SO ２ NASO ２ -), and the electrolyte composition according to any one of [1] to [5], having at least one functional group selected from the group consisting of. [7] The electrolyte composition according to any one of [1] to [6], wherein the organic solvent contains at least one selected from the group consisting of carbonate solvents, ether solvents, fluorine solvents, nitrile solvents, lactone solvents, phosphate ester solvents, and sulfone solvents. [8] The electrolyte composition according to any one of [1] to [7], further containing an alkali metal salt. [9] An electrode containing an electrolyte, wherein the electrolyte is the electrolyte composition according to any one of [1] to [8].

[10] A secondary battery including the electrode according to [9].

[11] A secondary battery including an electrolyte containing the electrolyte composition according to any one of [1] to [8].

[0008] According to the present disclosure, an electrolyte composition excellent in ionic conductivity can be provided.

[0009] Hereinafter, embodiments of the present disclosure will be described. However, the following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents. In this specification, a numerical range indicated by the symbol "~" includes a lower limit value and an upper limit value. That is, the numerical range indicated by "x~y" means x or more and y or less.

[0010] Unless otherwise specified, the materials exemplified herein may be used individually or in combination of two or more. The content of each component in a composition means the total amount of any multiple substances present in the composition, unless otherwise specified, if there are multiple substances corresponding to each component in the composition.

[0011] One embodiment of the electrolyte composition comprises a polymer, inorganic particles, and an organic solvent. The inorganic particles contain N as an adsorbent gas. ２ The specific surface area measured by the BET multipoint method using BET(N) is expressed as BET(N) ２ ) and H as the adsorbent gas ２ The specific surface area measured by the BET multipoint method using O is BET(H ２ When O), the above BET(N ２ The above BET(H ２ The ratio of O) is 0.30 or higher. The above electrolyte composition may contain metal ions.

[0012] In electrolyte compositions containing polymer electrolytes, attempts have been made to facilitate the movement of metal ions compared to the case of polymer electrolytes alone by filling them with inorganic particles, thereby forming an ion conduction zone through the interaction between the inorganic particles and the polymer electrolyte near the inorganic particles. Such movement of metal ions can be called particle surface conduction type ion conduction. In the electrolyte composition according to this disclosure, the inorganic particles blended into the electrolyte composition are BET(N ２ BET(H) ２ A composition is used in which the ratio of O) falls within a predetermined range. The reason why having the above-described configuration results in an electrolyte composition with excellent ionic conductivity is not entirely clear, but the inventors of the present invention deduce the following.

[0013] N ２ When H is used as the adsorbed gas, the specific surface area corresponds to the specific surface area that reflects the entire surface of the inorganic particles. ２ When O is the adsorbed gas, the specific surface area corresponds to the specific surface area that reflects the portion of the inorganic particle's surface that has polar functional groups (e.g., OH groups). That is, BET(N) ２ BET(H)２ The ratio of O) can be said to be an indicator of the extent to which polar functional groups are distributed on the surface of the inorganic particles. When polar functional groups are present on the surface of the inorganic particles, the positively charged constituent element (H in the case of an OH group) in that functional group interacts with the counter anion of the cation flowing through the electrolyte composition, weakening the negative charge of the counter anion and thereby loosening the binding of the cation. Similarly, the presence of a negatively charged constituent element (O in the case of an OH group) in the functional group on the surface of the inorganic particles creates an electrostatic attraction between the cation's counter anion and the negatively charged constituent element of the functional group. As a result, the electrostatic attraction felt by the cation is weakened, and the binding of the cation is loosened. Due to these effects, the electrolyte composition is presumed to have superior ionic conductivity compared to a composition containing inorganic particles that do not meet the above requirements. The cation may be, for example, a metal ion. The metal ion may be, for example, an alkali metal ion, an alkaline earth metal ion, etc.

[0014] The polymer may be, for example, polyethylene oxide, or a polymer having anionic groups and a metal ion as a countercation to the anionic groups. The metal ion in the polymer having anionic groups and a metal ion as a countercation to the anionic groups may be an alkali metal ion, an alkaline earth metal ion, etc., and the metal ion may be a metal ion contained in the electrolyte composition.

[0015] A polymer having an anionic group and an alkali metal ion as a countercation to the anionic group (hereinafter, as may be referred to as "polymer (A)") may have the anionic group as a side chain with respect to the main chain structure of the polymer, or it may have the anionic group in the main chain structure. As described above, polymer (A) has the ability to conduct alkali metal ions by having anionic groups.

[0016] The structure of polymer (A) is not particularly limited, but examples include polymers having a carbon chain as the main chain. This carbon chain may be formed by radical addition polymerization of monomers having ethylenically unsaturated groups.

[0017] The alkali metal ion conduction performance of polymer (A) may be evaluated by the alkali metal ion transportity, and the alkali metal ion transportity of polymer (A) may be, for example, 0.4 or higher, 0.5 or higher, 0.6 or higher, or 0.7 or higher.

[0018] In this specification, the transportity of alkali metal ions in polymer (A) refers to the transportity measured using the polymer under consideration under at least one of the following conditions (X) and (Y): Condition (X): A composition is prepared containing 33% by mass of the polymer and 67% by mass of a nonionic plasticizer, and the transportity of alkali metal ions is measured at room temperature (25°C). Condition (Y): A composition is prepared containing 31.9% by mass of the polymer, an alkali metal salt, and the remaining amount of nonionic plasticizer, with an alkali metal ion concentration of 0.3 mol / L, and the transportity of alkali metal ions is measured at room temperature (25°C).

[0019] In the above conditions (X) and (Y), the alkali metal ions contained in the composition to be measured may be countercations of the anionic functional groups of the polymer. Furthermore, the nonionic plasticizer may be at least one of a solvent and other resins such as fluororesins. The 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. The solvent may be a mixed solvent of ethylene carbonate and propylene carbonate (volume ratio of 1:1). The fluororesin may be a resin having a carbon chain as its main chain. The carbon chain in the fluororesin may be formed by radical polymerization of ethylenically unsaturated groups. The fluororesin may be PVDF-HFP.

[0020] Polymer (A) has anionic groups and alkali metal ions as countercations to the anionic groups, but may also have alkali metalized functional groups that contain the anionic groups and alkali metal ions. Polymer (A) may also have alkali metalized functional groups as side groups.

[0021] In this specification, an alkali-metallated functional group refers to a group in which an anionic functional group, which is the conjugate base of the acidic form of the functional group, forms a salt with an alkali metal ion. The alkali-metallated functional group may be a monovalent or a divalent or more-valent functional group, or a monovalent or divalent functional group.

[0022] Examples of alkali-metallated functional groups include alkali-metallated phenol groups, alkali-metallated carboxylic acid groups, alkali-metallated sulfonic acid groups, alkali-metallated carbonylsulfonylimide groups, alkali-metallated sulfonylimide groups, alkali-metallated alcohol groups, and alkali-metallated phosphate groups. Preferably, the alkali-metallated functional group includes at least one selected from the group consisting of alkali-metallated phenol groups, alkali-metallated carboxylic acid groups, alkali-metallated sulfonic acid groups, alkali-metallated carbonylsulfonylimide groups, and alkali-metallated sulfonylimide groups.

[0023] Alkali metallated phenol groups are -OA groups (-O) in which the hydrogen atom of the phenolic hydroxyl group -OH is replaced by an alkali metal element A. － A ＋ This refers to a group, for example, a lithium-ionized phenol group. An alkali metallated carboxylic acid group is a -COOA group ([-COOH]) in which the hydrogen atom of a carboxylic acid group (-COOH group) is replaced by an alkali metal element A. － A ＋ This refers to a group, for example, a lithium carboxylic acid group. An alkali metallated sulfonic acid group is a sulfonic acid group (-SO ３ -SO4 (H group) where the H is replaced by alkali metal element A ３ A group ([-SO ３ ] － A ＋This refers to a group, for example, a lithium sulfonic acid group. An alkali metallated carbonyl sulfonylimide group is a carbonyl sulfonylimide acid group (-SO ２ -SO₂ (NH-CO group) where the H is replaced by an alkali metal element A ２ -NA-CO- group ([-SO ２ -N-CO-] － A ＋ This refers to a group, for example, a lithium carbonyl sulfonylimide group. An alkali metallized sulfonylimide group is a sulfonylimide acid group (-SO ２ -NH-SO ２ -SO4) is a group in which the H of the - group is replaced by an alkali metal element A. ２ -NA-SO ２ -Base ([-SO ２ -N-SO ２ -] － A ＋ This refers to a group, such as a lithium sulfonylimide group.

[0024] In the alkali metallized functional group described above, alkali metal element A may include at least one selected from the group consisting of lithium, sodium, potassium, rubidium, and cesium, or at least one selected from the group consisting of lithium, sodium, and potassium, or at least one of lithium and sodium, or lithium.

[0025] The alkali metal element A contained in polymer (A) may be one type or multiple types. If multiple alkali metal elements A are included, the content of the element with the highest content may be, for example, 80 mol% or more, 85 mol% or more, or 90 mol% or more, based on the total amount of alkali metal elements A. If multiple alkali metal elements A are included, the element with the highest content may be, for example, potassium, sodium, or lithium, or sodium, or lithium, or lithium.

[0026] Polymer (A) may have structural units having alkali-metallated functional groups (hereinafter, as may be referred to as "structural unit (A)"). Structural unit (A) may be, for example, a structural unit represented by the following general formula (A1), a structural unit represented by the following general formula (A2), etc. Note that in general formula (A1), R １ ~R ３ The structure excluding and Y, and in general formula (A2), R ４ , R ５ The structure excluding Z is also simply called an ethylene unit.

[0027] (In general formula (A1), Y represents an alkali-metallated monovalent group. R １ ~R ３ Each is independently a hydrogen atom or a monovalent substituent, or R １ and R ２ One of them is R ３ It forms a ring together with the other atom, and the other atom is a hydrogen atom or a monovalent substituent. １ ~R ３ It may have an alkali metallized group. １ ~R ３ At least one of these may be a functional group other than a hydrogen atom or a fluorine atom.

[0028] (In general formula (A2), Z represents an alkali-metallated divalent group. R ４ and R ５ Each is independently a hydrogen atom or a monovalent substituent, or R ４ and R ５ They come together to form a ring. R ４ and R ５ (It may have alkali-metallated groups.)

[0029] In general formula (A1), Y includes at least one alkali-metallated functional group. The alkali-metallated functional group in general formula (A1) may include, for example, at least one selected from the group consisting of alkali-metallated phenol groups, alkali-metallated carboxylic acid groups, alkali-metallated carbonylsulfonylimide groups, and alkali-metallated sulfonylimide groups. Polymer (A) may contain one or more structural units (A) having different functional groups as Y.

[0030] In general formula (A1), R １ ~R ３ If 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 general formula (A1), R １ ~R ３ At least one of them may be a hydrogen atom, and all of them may be hydrogen atoms.

[0031] In general formula (A1), R １ and R ２ One of them is R ３ When R is together with others to form a ring, １ or R ２ and R ３ This involves forming divalent substituents that bond to the two carbon atoms of the ethylene unit in general formula (A1).

[0032] If Y in general formula (A1) contains an alkali-metallated carboxylic acid group (-COOA group), Y may be the -COOA group itself, or it may be a monovalent organic group having a -COOA group. If 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 above organic group includes the carbon atoms that make up the -COOA group. A monovalent organic group having a -COOA group may have one or more -COOA groups, or it may have one -COOA group. In addition to the -COOA group, Y may have electron-withdrawing groups such as halogen atoms.

[0033] In general formula (A1), Y may be a group represented by -R ９ -COOA. Here, R ９ is a divalent organic group or a covalent bond (that is, Y is the -COOA group itself). The number of carbon atoms in the divalent organic group may be, for example, 1 to ９ 19, 1 to 14, 1 to 9, 1 to 4, 1, or 2. When R ９ contains carbon atoms, R ９ may be a divalent group other than a group in which all carbon atoms contained in R ９ are substituted with fluorine atoms. When R ９ contains carbon atoms, at least one of the carbon atoms contained in R ９ is bonded to a hydrogen atom or a substituent other than a fluorine atom.

[0034] When Y in general formula (A1) has a phenol hydroxyl group that has been alkali metalated, Y may be, for example, a group represented by R １０ -Y ２ . Here, R １０ is a divalent substituent (linking group) or a covalent bond, and may be a covalent bond. Y ２ may be a group having one or more -OA groups directly bonded to a carbon atom that is a ring member of an aromatic ring such as a benzene ring, a naphthalene ring, or an anthracene ring. Another ring structure may be condensed to the aromatic ring. For example, Y ２ may have a group represented by any of the following general formulas (A21) to (A Ａ１ 26).

[0035] (In general formula (A21), at least one of the R Ａ１ to R Ａ５ groups is an -OA group, and the rest are hydrogen atoms or monovalent substituents. The R Ａ３ group may be an -OA group. In general formula (A22), at least one of the R Ｂ１～ R Ｂ７ groups is an -OA group, and the rest are hydrogen atoms or monovalent substituents. At least one of the R Ｂ３ to R Ｂ６ groups may be an -OA group. In general formula (A23), at least one of the R[[ID= Ｃ１～ 46]]R Ｃ９At least one of the groups is an -OA group, and the rest are hydrogen atoms or monovalent substituents. R Ｃ２ ~R Ｃ８ At least one of the groups may be an -OA group. In general formula (A24), R Ｄ１～ R Ｄ６ At least one of the groups is an -OA group, and the rest are hydrogen atoms or monovalent substituents. R Ｄ３～ R Ｄ６ At least one of the groups may be an -OA group. In general formula (A**25**), R Ｅ１～ R Ｅ９ At least one of the groups is an -OA group, and the rest are hydrogen atoms or monovalent substituents. R Ｅ２ ~R.. [[ID=1...]] Ｅ８ At least one of the groups may be an -OA group. In general formula (A26), R Ｆ１～ R Ｆ９ At least one of the groups is an -OA group, and the rest are hydrogen atoms or monovalent substituents. R Ｆ１～ R Ｆ９ At least one of the groups may be an -OA group.)

[0036] The groups represented by general formulas (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, and the -OA group may be 1.

[0037] The monovalent substituent in general formulas (A21) to (A26) is preferably an electron-withdrawing group. Examples of the electron-withdrawing group include a halogen atom, a sulfonic acid group or its salt, a sulfonic acid ester, a nitro group, and a nitrile group. The halogen atom may be any of F, Cl, Br, and I.

[0038] The monovalent substituent in formulas (A21) to (A26) may be an organic group having 1 to 20 carbon atoms. The number of carbon atoms of the organic group may be, for example, 1 to 15, 1 to 10, 1 to 5, or 1 to 3.

[0039] When Y in general formula (A1) is R １０ -Y ２ is a group represented by, and the R １０ It should be noted that there seems to be an error in the original text where "In general formula (A**25**)" in line 12 has a wrong number in the superscript. I've translated it as it is but this might need to be corrected in the original content.If the substituent is divalent, 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 It may have a heterocycle, and may also have a ring containing an imide group.

[0040] When Y in general formula (A1) is an alkali-metallated sulfonic acid group, Y may be a group represented by the following general formula (A3). (In general formula (A3), R １９ (A is a covalent or divalent organic group. A is an alkali metal element.)

[0041] In general 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. In general formula (A3), R １９ If the divalent organic group is a hydrocarbon group, then at least one of the carbon atoms constituting the hydrocarbon group is bonded to a hydrogen atom. In other words, the divalent organic group in general formula (A3) is a group other than a total fluorinated hydrocarbon group.

[0042] Examples of alkali metallated sulfonic acid groups represented by the above general formula (A3) include -SO ３ A, -CH ２ -SO ３ A, and -C ６ H ４ -SO ３ A is one example.

[0043] When Y in the above general formula (A1) is an alkali-metallated sulfonylimide group, Y may be a group represented by the following general formula (A4). (In general formula (A4), R ２０ R is a covalent or divalent organic group. ２１ is a hydrogen atom or a monovalent substituent. A ＋ (It is an alkali metal ion.)

[0044] R in general formula (A4) ２０If the group 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.

[0045] When Y in the above general formula (A1) is an alkali-metallated carbonylsulfonylimide group, examples of Y include the group represented by the following general formula (A5-1) and the group represented by the following general formula (A5-2). (In general formulas (A5-1) and (A5-2), R ２０ R is a covalent or divalent organic group. ２１ is a hydrogen atom or a monovalent substituent. A ＋ (It is an alkali metal ion.)

[0046] R in general formula (A5-1) and general formula (A5-2) ２０ If the group 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.

[0047] If the structural unit (A) of polymer (A) has a structural unit represented by general formula (A2), then in general formula (A2), R ４ and R ５ When they come together to form a ring, R ４ and R ５ This involves forming divalent substituents bonded to the two carbon atoms of the ethylene unit of general formula (A2). These rings may be either carbocyclic or heterocyclic. The number of ring members in these rings may be, for example, 4 to 10, 5 to 8, 5, or 6. Substituents may be bonded to the carbon atoms or heteroatoms that are ring members.

[0048] In general formula (A2), Z is bonded to two carbon atoms of an ethylene unit to form a ring. This ring may be a carbocyclic ring or a heterocyclic ring. The ring may also be aliphatic or aromatic. Examples of heterocyclic rings include rings having imide groups, such as maleimide rings. Alkali metallized functional groups may be bonded to this 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.

[0049] The structural unit (A2) may be a group containing a maleimide ring having an alkali-metallated functional group, and an example of a structural unit represented by the following general formula (A6) is given. In the following general formula (A6), * indicates the position where the structural unit is bonded to other structural units. (In general formula (A6), X is a divalent organic group having 1 to 20 carbon atoms, and Y １ A is a monovalent organic group having a halogen atom or 1 to 20 carbon atoms, ＋ (It is an alkali metal ion.)

[0050] The number of carbon atoms in X in general formula (A6) may be, for example, 1 to 15, 2 to 10, or 3 to 8. If 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 are replaced with halogen atoms such as fluorine atoms, and may be a substituted phenylene group substituted with an alkyl group, halogen atom, electron-withdrawing group, etc.

[0051] Y in general formula (A6) １ If is a monovalent organic group, Y １ The number of carbon atoms in may be, for example, 1 to 15, 1 to 10, 1 to 8, 1 to 5, or 1 to 3. １If 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 are substituted with halogen atoms such as fluorine atoms, may be a fluorinated alkyl group having 1 to 5 carbon atoms, or may be a fluorinated alkyl group having 1 to 3 carbon atoms such as a trifluoromethyl group. The fluorinated alkyl group may be a total fluorinated alkyl group. １ If the element is a halogen atom, the halogen atom may be a fluorine atom or a chlorine atom, and may be a fluorine atom.

[0052] When a polymer (A) has a structural unit (A) represented by general formula (A2), and general formula (A2) includes an alkali-metallated phenolic hydroxyl group, Z in general formula (A2) can be, for example, a group represented by the following general formula (A7). (In general formula (A7), R １８ (A is a covalent or divalent organic group. A is an alkali metal element.)

[0053] In general formula (A7), 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. １８ If it contains carbon atoms, R １８ R １８ All carbon atoms contained in the group may be divalent groups other than those in which fluorine atoms are substituted. １８ If it contains carbon atoms, R １８ At least one of the carbon atoms contained in is bonded to a substituent other than a hydrogen atom or a fluorine atom.

[0054] Examples of alkali metallated phenol groups represented by general formula (A7) include -C ６ H ４ -OA and -CH ２ -C ６ H ４ - Examples include OA (Office Automation).

[0055] When a polymer (A) has a structural unit (A) represented by general formula (A2), and general formula (A2) includes an alkali-metallated carboxylic acid group, Z in general formula (A2) can be, for example, a group represented by the following general formula (A8). (In general formula (A8), R １８ (A is a covalent or divalent organic group. A is an alkali metal element.)

[0056] In general formula (A8), 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. １８ If it contains carbon atoms, R １８ R １８ All carbon atoms contained in the group may be divalent groups other than those in which fluorine atoms are substituted. １８ If it contains carbon atoms, R １８ At least one of the carbon atoms contained in is bonded to a substituent other than a hydrogen atom or a fluorine atom.

[0057] Examples of alkali metallated carboxylic acid groups represented by general formula (A8) include -COOA and -CH ２ - COOA and others are examples.

[0058] When a polymer (A) has a structural unit (A) represented by general formula (A2), and general formula (A2) includes an alkali-metallated sulfonic acid group, Z in general formula (A2) can be, for example, a group represented by the following general formula (A9). (In general formula (A9), R １８ (A is a covalent or divalent organic group. A is an alkali metal element.)

[0059] In general formula (A9), 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. １８ If it contains carbon atoms, R １８ R １８ All carbon atoms contained in the group may be divalent groups other than those in which fluorine atoms are substituted.１８ If it contains carbon atoms, R １８ At least one of the carbon atoms contained in is bonded to a substituent other than a hydrogen atom or a fluorine atom.

[0060] Examples of alkali metallated sulfonic acid groups represented by general formula (A9) include -SO ３ A, -CH ２ -SO ３ A, and -C ６ H ４ -SO ３ A is one example.

[0061] When a polymer (A) has a structural unit (A) represented by general formula (A2), and general formula (A2) includes an alkali-metallated carbonylsulfonylimide group, examples of Z in general formula (A2) include the group represented by the following general formula (A10-1) and the group represented by the following general formula (A10-2). (In general formulas (A10-1) and (A10-2), R １８ R is a covalent or divalent organic group. ２１ (where A is a hydrogen atom or a monovalent substituent; A is an alkali metal element.)

[0062] In general formulas (A10-1) and (A10-2), 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. １８ If it contains carbon atoms, R １８ R １８ All carbon atoms contained in the group may be divalent groups other than those in which fluorine atoms are substituted. １８ If it contains carbon atoms, R １８ At least one of the carbon atoms contained in is bonded to a substituent other than a hydrogen atom or a fluorine atom.

[0063] Polymer (A) may further contain structural units having functional groups that function as anion receptors (hereinafter also referred to as structural unit (B)), in addition to structural units having alkali-metallated functional groups.

[0064] The electrolyte composition according to this embodiment may further include, in addition to polymer (A), other polymers that do not contain alkali metallized functional groups but have the ability to conduct alkali metal ions. Examples of other polymers include polymers having structural unit (B) but not structural unit (A) (hereinafter referred to as polymer (B)).

[0065] Structural unit (B) functions as an anion receptor. In this specification, "anion receptor" refers to a chemical species that captures an anion by forming electrostatic interactions, hydrogen bonds, or acid-base complexes with the anion.

[0066] Structural unit (B) captures the counter anion of the alkali metal ion in the alkali metal salt and promotes the dissociation of the counter anion and the alkali metal ion. Therefore, the inclusion of polymer (B) in the electrolyte composition can further increase the mobility of alkali metal ions. On the other hand, since the counter anion is captured by polymer (B) via structural unit (B), the mobility of the counter anion decreases. As a result, when the electrolyte composition contains polymer (B), the transport rate of alkali metal ions in the electrolyte composition can be further improved. In addition, since the mobility of alkali metal ions increases, the conductivity of alkali metal ions also tends to improve.

[0067] 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 No. 6,022,643, U.S. Patent No. 5,705,689, and U.S. Patent No. 6,120,941, among others.

[0068] A functional group that functions as an anion receptor may be Lewis acidic. In this case, the functional group that functions as an anion receptor can accept the lone pair of electrons of an anion and capture the anion species by forming an acid-base complex. Examples of Lewis acidic functional groups include those having electron-deficient atoms. In this specification, an "electron-deficient atom" refers to an atom that is covalently bonded to another atom, but whose outermost electron shell does not form an octet. Examples of electron-deficient atoms include atoms belonging to Group 13 of the periodic table, and more specifically, at least one of aluminum and boron, or boron.

[0069] A functional group having the function of anion receptor may be a group having an azaether moiety. A group having an azaether moiety is a group having an azaether compound as a substituent, and the azaether compound has the -O- of the ether compound as -NR Ｅ - (Here, R Ｅ The compound is one in which ( is a hydrogen atom or an organic group) is replaced. The azaether portion may be either a linear azaether portion or a cyclic azaether portion, and may have both a linear azaether portion and a cyclic azaether portion. The group having the azaether portion may have an electron-withdrawing group in the hydrocarbon portion, for example.

[0070] The structural unit (B) may be, for example, a structural unit represented by the following general formula (B). The polymer (B) may contain at least one structural unit that satisfies the requirements of the structural unit represented by the following general formula. Note that in the following general formula (B), R １１ ~R １３ The structure excluding W is also simply called an ethylene unit. In the general formula (B) below, * indicates the position where structural unit (B) is bonded to other structural units. (In general formula (B), W is a functional group that functions as an anion receptor, and R １１ ~R １３ Each is independently a hydrogen atom or a monovalent substituent, or R １１ and R １３One of them is R １２ It forms a ring together with the other atom, and the other atom is a hydrogen atom or a monovalent substituent. １１ ~R １３ (One or more of these atoms may be hydrogen atoms, or all of them may be hydrogen atoms.)

[0071] In general formula (B), R １１ ~R １３ If the substituent is monovalent, 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.

[0072] In general formula (B), R １１ ~R １３ If the substituent is monovalent, 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.

[0073] In general formula (B), R １１ and R １３ One of them is R １２ When R is together with others to form a ring, １１ or R １２ and R １３ This involves forming divalent substituents bonded to the two carbon atoms of the ethylene unit of general formula (B). These rings may be either carbocyclic or heterocyclic. The number of ring members in these rings may be, for example, 4 to 10, 5 to 8, 5, or 6. Substituents may be bonded to the carbon atoms or heteroatoms that are ring members.

[0074] In general formula (B), W preferably has a functional group represented by the following general formula (B1). (In general formula (B1), W Ｂ R is an atom belonging to Group 13 of the periodic table. １５ R is a covalent or divalent organic group.１６ and R １７ Each of these is independently a hydrogen atom, an -OH group, a halogen atom, or a monovalent organic group, or together they form a ring. １６ and R １７ (These may be the same group or different groups.)

[0075] W in general formula (B1) Ｂ This may be at least one of an aluminum atom and a boron atom, and may be a boron atom.

[0076] R in general formula (B1) １５ If the group 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 If it is a divalent organic group, the organic group can be, for example, 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. １５ The bond may be covalent.

[0077] R in general formula (B1) １６ or R １７ If R is a halogen atom, １６ or R １７ R may be any of the following: a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and may be a fluorine atom. １６ or R １７ They may be the same or different.

[0078] R in general formula (B1) １６ or R １７ If it 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 １７For example, 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.

[0079] The group represented by general formula (B1) may be a functional group represented by the following formula (B1a) or a functional group represented by the following general formula (B1b). (In general formula (B1a), R １５ X is a covalent or divalent organic group, １１ and X １２ Each of these is independently an oxygen atom or a covalent bond. １１ If the bond is covalent, then R ２２ X is a hydrogen atom, a halogen atom, or a monovalent organic group. １１ If R is an oxygen atom, ２２ X is a hydrogen atom or a monovalent organic group. １２ If the bond is covalent, then R ２３ X is a hydrogen atom, a halogen atom, or a monovalent organic group. １２ If R is an oxygen atom, ２３ X is a hydrogen atom, a halogen atom, or a monovalent organic group. １１ and X １２ (If each of these is an oxygen atom, it may be an oxygen atom that forms an ether bond.) (In general formula (B1b), R １５ X is a covalent or divalent organic group, １３ and X １４ Each of these is an oxygen atom or a covalent bond, R ２４ (This is a divalent organic group.)

[0080] In general formula (B1a), R ２２ Or R ２３If 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 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. ２２ Or R ２３ If the element is a halogen atom, the halogen atom may be a fluorine atom.

[0081] R in general formula (B1a) ２２ and R ２３ These are, independently, -F and -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 between 0 and 4, and may be an integer between 0 and 3.) -CF ３ ien-CH ２ CF ３ ien-CH ２ CF ２ CF ３ , -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.)

[0082] In the general formula (B1b), R ２４The group is a divalent organic group, but 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 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.

[0083] R in general 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 - Examples include those in which these hydrogen atoms are partially or completely replaced with fluorine. ２４ More specifically, -C(CH ３ ) ２ -C(CH ３ ) ２ - That's fine.

[0084] Polymer (A) may further have structural units (C) that are neither structural unit (A) nor structural unit (B). Structural unit (C) may include, for example, a structural unit represented by the following general formula (C). In the following general formula (C), * indicates a position where structural unit (C) bonds with other structural units. (In general formula (C), R ２５ R is a hydrogen atom or a monovalent substituent, ２６ ~R ２８ Each is independently a hydrogen atom or a monovalent substituent, or R ２６ and R ２７ One of them is a hydrogen atom or a monovalent substituent, and the other is R２８ (They form a ring together.)

[0085] In general formula (C), R ２５ R may be a monovalent organic group. ２５ The number of carbon atoms it has may be, for example, 1 to 40, 1 to 20, 2 to 15, or 4 to 13. The above monovalent organic group is -Z １ -R ２９ The base may be represented by . Here, Z １ is a divalent linking group, for example, covalent bonds, -O-, -S-, -C(=O)-, -C(=O)O-, -OC(=O)-, -C(=O)NR ３８ -, or -NR ３９ It may be a group represented as C(=O)-. １ If the bond is covalent, -O-, -S-, -C(=O)-, -C(=O)O-, or -OC(=O)-, then R ２９ This is a hydrogen atom or a monovalent organic group.

[0086] The above divalent linking group Z １ However, -C(=O)NR ３８ - If R ２９ , R ３８ Each of these is either a hydrogen atom or a monovalent organic group, or R ２９ R ３８ Together with it, it forms a ring. Z １ However, -NR ３９ If C (= O) -, then R ２９ , R ３９ Each of these is either a hydrogen atom or a monovalent organic group, or R ２９ R ３９ It forms a ring together with R. ２９ , R ３８ and R ３９ The number of carbon atoms in a monovalent organic group may be 1 to 20 or 1 to 10. ３８ If it is a monovalent organic group, it may be a monovalent hydrocarbon group having 1 to 20 carbon atoms.

[0087] The above divalent linking group Z １ If the bond is covalent or -C(=O)O-, then R ２９This may be a monovalent hydrocarbon group having a hydrogen atom or 1 to 20 carbon atoms. １ The bond is covalent and R ２９ If R is a hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. ２９ This may be a monovalent organic group other than a hydrocarbon group, or a hydrocarbon group having a cyclic structure.

[0088] In a group having an aromatic ring (for example, the above-mentioned aromatic hydrocarbon group), a monovalent substituent may be attached to the aromatic ring. Examples of monovalent substituents include monovalent organic groups, and monovalent organic groups include substituted or unsubstituted hydrocarbon groups, formula: -R ６１ - (W １ -R ６２ ) ｎ -W ２ R ６３ Examples of bases represented by the formula: -R ６１ - (W １ -R ６２ ) ｎ -W ２ R ６３ The group represented by may be bonded to a benzene ring. １ This may be a divalent group such as -O-, -S-, -C(=O)-, or -C(=O)O-, and may also be -O-. ２ This may be a divalent group such as -O-, -S-, -C(=O)-, or -C(=O)O-, and may also be -O-.

[0089] R in the monovalent organic group described above ６１This is a covalent or divalent organic group. The divalent organic group may be a divalent hydrocarbon group. The number of carbon atoms in the divalent hydrocarbon group may be, for example, 1 to 8, 1 to 5, or 1 to 3. The hydrogen atoms bonded to the divalent hydrocarbon group may be substituted by substituents such as monovalent substituents (i.e., it may be a substituted hydrocarbon group). Examples of substituents include halogen atoms such as fluorine atoms. Specifically, 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 in these groups are substituted with halogen atoms such as fluorine atoms, or it may be a methylene group.

[0090] R in the monovalent organic group described above ６２ This is a divalent organic group, and may be a divalent hydrocarbon group. The number of carbon atoms in the divalent hydrocarbon group may be, for example, 1 to 8, 1 to 5, or 1 to 3. The hydrogen atoms bonded to the above divalent hydrocarbon group may be substituted with substituents such as monovalent substituents (i.e., it 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 are substituted with halogen atoms such as fluorine atoms, and may be an ethylene group.

[0091] The above formula: -R ６１ - (W １ -R ６２ ) ｎ -W ２ R ６３ In the group represented by , n may be, for example, 1 to 10, 1 to 5, or 1 to 3. The above n may be an integer or a rational number (for example, when n is the average value over the structural units (C) of the polymer). Within one structural unit R ６２ If there are multiple instances, they may be different or identical.

[0092] R in the monovalent organic group described above ６３This 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 atom bonded to the monovalent hydrocarbon group may be substituted by a substituent such as a monovalent substituent (i.e., it may be a substituted hydrocarbon group). Examples of substituents include halogen atoms such as fluorine atoms. 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 of these groups are substituted with halogen atoms such as fluorine atoms, and may be a methyl group.

[0093] If polymer (A) has structural units (C), structural units (C) may include structural units derived from monomers represented by the following general formula (C1). (In the general formula (C1), m is between 0 and 4, and n is between 0 and 10. R ３１ This 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, or it may be a methyl group.

[0094] In general formula (C1), m may be, for example, 1 to 3, 1 to 2, or 1. m may be an integer and may be the average value over all structural units derived from the monomer represented by general formula (C1) contained in the polymer (in this case, m is a rational number). In general formula (C1), n ​​may be, for example, 1 to 4, or 1 to 3. n may be an integer and may be the average value over all structural units derived from the monomer represented by general formula (C1) contained in the polymer (in this case, n is a rational number).

[0095] If polymer (A) has structural units (C), then R ２６ and R ２７ One of them is R ２８ When they form a ring together, the ring members of the ring may be, for example, 4 to 10, 4 to 8, or 5 to 7. In the structural unit (C), R ２７ R ２８ When forming a ring together, the structural unit (C) may be a structural unit represented by the following general formula (C2). (In general formula (C2), X is an oxygen atom or -NR ３１ It is a tertiary amino group represented by -, R ３１ is a monovalent organic group, R ２５ and R ２６ Each of these is independently either a hydrogen atom or a monovalent substituent.

[0096] In the general formula (C2), X is -NR ３１ If it is a tertiary amino group represented by -, R ３１ The number of carbon atoms in R may be, for example, 1 to 20, 1 to 15, or 2 to 10. ３１ This 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.

[0097] The ratio of structural unit (A) to the total structural units contained in polymer (A) may be, for example, 0.2 to 0.95, 0.2 to 0.8, 0.3 to 0.7, or 0.4 to 0.6.

[0098] The ratio of structural unit (C) to the total structural units contained in 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 structural unit (C) to the total structural units contained in 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.

[0099] The total ratio of structural unit (A) and structural unit (C) to the total structural units contained in 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.

[0100] The content of structural units (A) relative to the total mass of polymer (A) may be, for example, 25 to 95% by mass, 40 to 90% by mass, or 50 to 90% by mass.

[0101] The content of structural units (C) relative to the total mass of polymer (A) may be, for example, 5 to 75% by mass, 10 to 60% by mass, or 10 to 50% by mass. The content of structural units (C) relative to the total mass of polymer (A) may be, for example, 75% by mass or less, 60% by mass or less, 50% by mass or less, or 25% by mass or less.

[0102] The total content of structural unit (A) and structural unit (C) relative to the total mass of polymer (A) may be, for example, 90% by mass or more, 95% by mass or more, or 98% by mass or more.

[0103] If polymer (A) contains structural units (B), the molar ratio m of structural units (B) to the total structural units contained in 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.

[0104] The content of structural units (B) relative to the total mass of polymer (A) may be, for example, more than 10% by mass and 95% by mass or less, 15 to 95% by mass, 20 to 80% by mass, 25 to 60% by mass, or 30 to 45% by mass.

[0105] The number-average molecular weight (Mn) of 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 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 polymer (A) may be, for example, 1.0 to 5.0, 1.2 to 3.0, or 1.3 to 2.5.

[0106] The number-average molecular weight and weight-average molecular weight of polymer (A) in this specification can be measured by gel permeation chromatography (GPC) under the following conditions. For the preparation of the calibration curve, a standard sample of polymethyl methacrylate (manufactured by Polymer Laboratories, Mn 800 to 2,200,000) shall be used as the standard substance. <GPC Measurement Conditions> Apparatus: JASCO Corporation, High-Performance Liquid Chromatograph PU-2080 precision pump RI-2031 reflective-index detector UV-2075 UV / vis detector 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

[0107] The content of polymer (A) in the electrolyte composition according to this embodiment may be, for example, 10 to 95 volume%, 13 to 90 volume%, 15 to 80 volume%, 17 to 70 volume%, or 20 to 65 volume%, based on the total amount of the electrolyte composition. If the content of polymer (A) is 10 volume% or more based on the total amount of the electrolyte composition, the decrease in ionic conductivity can be further suppressed. If the content of polymer (A) is 90 volume% or less based on the total amount of the electrolyte composition, the decrease in the effect due to compounding with inorganic fillers can be suppressed.

[0108] The methods for producing polymer (A) and polymer (B) are not particularly limited, but for example, they can be produced by carrying out polymerization reactions such as radical addition polymerization on the corresponding monomers.

[0109] The electrolyte composition according to this embodiment includes inorganic particles. The inorganic particles are N as an adsorbent gas. ２ The specific surface area measured by the BET multipoint method using BET(N) is expressed as BET(N) ２ ) and H as the adsorbent gas ２The specific surface area measured by the BET multipoint method using O is BET(H ２ When O), the above BET(N ２ The above BET(H ２ O) ratio (BET(H ２ O) / BET(N ２ The value of () is 0.30 or greater. BET(H ２ O) / BET(N ２ The value of ) can be adjusted, for example, by changing the grinding conditions and drying conditions of inorganic particles in the manufacturing process.

[0110] The above BET(H ２ O) / BET(N ２ The lower limit of the value of ) may be, for example, 0.33 or higher, 0.34 or higher, 0.35 or higher, 0.40 or higher, 0.50 or higher, 0.60 or higher, 0.70 or higher, or 0.80 or higher. ２ O) / BET(N ２ The fact that the lower limit of the value of ) is within the above range corresponds to a wider distribution of polar functional groups that adsorb water vapor on the inorganic particle surface, and the movement of metal ions in the conduction band formed near the inorganic particle surface becomes easier. This makes it possible to further improve the ionic conductivity of the electrolyte composition. ２ O) / BET(N ２ The upper limit of the value of ) may be, for example, 1.5 or less, 1.2 or less, or 1.0 or less.

[0111] BET(N) in this specification ２ ) and BET(H ２ O) represents the values ​​measured under the following conditions:

[0112] Nitrogen adsorption BET specific surface area (BET(N) ２ The measurement was performed using the multi-point method with the "BELSORP-mini II" (product name) manufactured by Microtrac-Bell. The measurement conditions were as follows, and the nitrogen adsorption cross-section was set to 0.162 nm. ２ The analysis range for nitrogen adsorption BET specific surface area is P / P ０The result was calculated by selecting two points with good linearity within the range of 0.05 to 0.2 and analyzing them. Note that BET(N) ２ ) Considering the total surface area, sufficient adsorption can be obtained (when the total surface area is 1 m² ２ The sample amount was adjusted to achieve the above result. <Measurement conditions_Nitrogen adsorption> Sample amount: 0.05-0.1 g Adsorption temperature: -196°C Saturated vapor pressure: Measured maximum adsorption pressure: P / P ０ = 0.99 Adsorption equilibrium time: 500 seconds

[0113] Water vapor adsorption BET specific surface area (BET(H) ２ The measurement of O)) was performed using the multi-point method with the "BELSORP-aqua3" (product name) manufactured by Microtrac-Bel. The measurement conditions for each were as follows, and the adsorption cross-section of water was set to 0.125 nm. ２ The analysis range for the specific surface area of ​​water vapor adsorption BET is P / P ０ The analysis was performed and calculated under the conditions of =0.1 to 0.2. Note that BET(H ２ O) Considering the total surface area, a sufficient amount of adsorption (total surface area is 1 m²) ２ The sample amount was adjusted to obtain the above results. <Measurement conditions_Water vapor adsorption> Sample amount: 0.15-0.3 g Pretreatment conditions: Air constant temperature bath temperature: 80°C, heated at 150°C for 8 hours under vacuum Adsorption temperature: 25°C Saturated vapor pressure: 3.169 kPa Maximum adsorption pressure: P / P ０ = 0.95 Adsorption equilibrium time: 500 seconds

[0114] The inorganic particles may be, for example, oxide particles, nitride particles, carbide particles, carbon particles, sulfur particles, and silicate mineral particles, and may be oxide particles from the viewpoint of improving the number of polar functional groups on the surface of the inorganic particles.

[0115] 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.

[0116] The upper limit of the average particle diameter of the inorganic particles may be, for example, 200 nm or less, 150 nm or less, 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, 60 nm or less, or 50 nm or less. By having the upper limit of the average particle diameter within the above range, the specific surface area of ​​the inorganic particles increases, which can further expand the conduction band of metal ions in the electrolyte composition. The lower limit of the average particle diameter of the inorganic particles may be, for example, 1 nm or more, 3 nm or more, or 5 nm or more. By having the lower limit of the average particle diameter within the above range, particle aggregation is further suppressed, resulting in a more homogeneous electrolyte composition. The average particle diameter of the inorganic particles may be adjusted within the above range, for example, 1 to 200 nm, 3 to 200 nm, 3 to 150 nm, 5 to 100 nm, 5 to 80 nm, or 5 to 50 nm.

[0117] In this specification, the average particle size refers to the particle size (D50) at which the cumulative value from the smallest particle size reaches 50% in the volume-based particle size distribution measured by a laser diffraction particle size analyzer. Examples of the laser diffraction particle size analyzer that can be used include the "SALD2200" (product name) and "SALD2300" (product name) manufactured by Shimadzu Corporation.

[0118] The inorganic particle content in the electrolyte composition according to this embodiment may be, for example, 5 to 70 volume%, 7 to 60 volume%, 10 to 50 volume%, 12 to 40 volume%, or 15 to 30 volume%, based on the total volume of the electrolyte composition. If the inorganic particle content is 5 volume% or more based on the total volume of the electrolyte composition, it is possible to suppress the decrease in the effect of compounding with inorganic fillers. If the inorganic particle content is 70 volume% or less based on the total volume of the electrolyte composition, it is possible to further suppress the decrease in ionic conductivity.

[0119] The electrolyte composition according to this embodiment contains an organic solvent. In the electrolyte composition, polymer (A) may be swollen with the organic solvent. Examples of organic solvents include aprotic solvents. The organic solvent may contain, for example, one or more solvents selected from the group consisting of carbonate solvents, ether solvents, fluorine solvents, nitrile solvents, phosphate ester solvents, and sulfone solvents, and may contain a carbonate solvent.

[0120] The carbonate solvent may be, for example, a linear carbonate and a cyclic carbonate. The linear carbonate may be, for example, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, etc. The cyclic carbonate may be, for example, ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, etc.

[0121] The ether solvent may be, for example, a linear ether and a cyclic ether. The linear ether may be, for example, 1,2-dimethoxyethane, 1,2-diethoxyethane, and ethoxymethoxyethane. The cyclic ether may be, for example, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, and the like.

[0122] The fluorine-based solvent may be, for example, hydrofluorocarbons, hydrofluoroethers, hydrofluoroolefins, and 2,2,2-trifluoro-N,N-dimethylacetamide. Hydrofluorocarbons may be, for example, perfluorooctane. Hydrofluoroethers may be, for example, methyl nonafluorobutyl ether, ethyl nonafluorobutyl ether, and the like. Hydrofluoroolefins may be, for example, 1,3,3,3-tetrafluoropropene.

[0123] Nitrile-based solvents may include, for example, acetonitrile and succinonitrile. Lactone-based solvents may include γ-butyrolactone.

[0124] Phosphate ester solvents may include, for example, trimethyl phosphate (TMP), triethyl phosphate (TEP), and tris(2,2,2-trifluoroethyl) phosphate (TFEP).

[0125] The sulfone solvent may be, for example, sulfolane and 3-methylsulfolane.

[0126] In addition to the solvents mentioned above, the organic solvent may further include, for example, solvents having a sulfonyl group, amide solvents, organic solvents having a carbonyl group (excluding amide compounds), and nitrogen-containing aromatic compounds. Solvents having a sulfonyl group may be, for example, dimethyl sulfoxide (DMSO). Amide solvents may be, for example, dimethylformamide (DMF) or dimethylacetamide (DMA). Organic solvents having a carbonyl group (referring to carbonyl compounds other than amide compounds such as -C(=O)-, esters, ketones, and aldehydes) may be, for example, acetone. Nitrogen-containing aromatic compounds (compounds containing nitrogen as a ring member of an aromatic ring, which may be monocyclic or fused ring systems) may be, for example, pyridine.

[0127] The amount of 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 per 100 parts by mass of polymer contained in the electrolyte composition.

[0128] The electrolyte composition according to this embodiment may further contain other components in addition to the polymer, inorganic particles, and organic solvent described above. These other components may include, for example, other resins (such as binder resins, resins other than polymers (A) and (B)), porous materials, alkali metal salts, film-forming additives, nonwoven fabrics or other fabrics, viscosity modifiers, and anion receptors.

[0129] Other resins may be fluororesins, etc. Fluorine-based resins may be resins having a carbon chain as their main chain. The carbon chain may be formed by radical polymerization of ethylenically unsaturated groups. Examples of fluororesins include polytetrafluoroethylene (PTFE), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), and polyvinylidene fluoride (PVDF).

[0130] The content of other resins in the electrolyte composition may be, for example, 0.1 to 20% by mass, 0.5 to 10% by mass, or 1 to 5% by mass, relative to the total amount of the electrolyte composition. The content of other resins may be 10 to 200 parts by mass, or 50 to 150 parts by mass, per 100 parts by mass of polymer.

[0131] The porous material may be a porous material made of resin. The porous material may be, for example, a porous polyolefin membrane and a porous ceramic membrane.

[0132] Examples of alkali metal salts include MF, MCl, MBr, MI, and MNO. ３ , MClO ４ MPF ６ MBF ４ M ２ SO ４ , M[(C ｈ F ２ｈ＋１ ) SO ３ ] (h is 0-3), M[(C ｈ F ２ｈ＋１ ) SO ２ ] ２ N (h is 0-3), M {[(C ｈ F ２ｈ＋１ ) SO ２ ]N[(C ｉ F ２ｉ＋１ ) SO ２]} (h, i are 0 to 3), and MBOB (BOB is bisoxalatoborate), etc. (The above M represents an alkali metal element and may be the same as or different from the alkali metal element A mentioned above). The above alkali metal M is not particularly limited as long as it is an element classified as an alkali metal, but for example it may contain lithium, sodium, or potassium, may contain lithium or sodium, or may contain lithium.

[0133] The alkali metal salt content 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 alkali metal ions contained in the alkali metal salt, relative to the total amount of structural units (A) of the polymer (A).

[0134] A film-forming additive is a compound that can form a film (electrolyte interface, SEI) on the electrode surface by an electrolytic reaction. Therefore, the film-forming additive may also be an SEI-forming agent. The film-forming additive may be at least one of an electrolytically oxidatively polymerizable compound and an electrolytically reductively polymerizable compound, but it may be an electrolytically reductively polymerizable compound. By using an electrolytically reductively polymerizable compound, a film can be formed on the negative electrode.

[0135] The amount 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 per 100 parts by mass of polymer (A).

[0136] The electrolyte composition may be molded into a film or pellet form and used as a molded body.

[0137] The method for producing the electrolyte composition is not particularly limited, but may include mixing the polymer, the inorganic particles, and the organic solvent. In this case, alkali metal salts and the like may also be added.

[0138] The electrolyte compositions described above can be used, for example, as compositions for forming electrolytes in electrode compositions, electrodes, batteries, and capacitors.

[0139] One embodiment of the electrode composition has an electrolyte, and the electrolyte may include the electrolyte composition described above. The electrolyte composition of this embodiment may be used as an electrode composition, or it may be included in at least one of the positive electrode and the negative electrode. That is, the electrolyte composition described above is suitable as an electrode composite material. An electrode made of the electrode composition may have excellent ion conductivity within the electrode.

[0140] One embodiment of an electrode is an electrode containing an electrolyte, wherein the electrolyte contains the above-described electrolyte composition.

[0141] One embodiment of the battery and capacitor comprises the electrodes described above. Another embodiment of the battery and capacitor comprises an electrolyte containing the electrolyte composition described above. The battery may be, for example, a primary battery or a secondary battery. The secondary battery may be an alkali metal ion secondary battery that charges and discharges by the movement of alkali metal ions. The alkali metal ion secondary battery may be, for example, a lithium-ion secondary battery, a sodium-ion secondary battery, and the like.

[0142] The battery configuration may include a positive electrode, a negative electrode, and an electrolyte (such as an electrolyte layer) disposed between the positive and negative electrodes. The electrolyte may include an electrolyte other than the electrolyte formed from the electrolyte composition according to this disclosure.

[0143] The positive electrode may be a layer containing a positive electrode material formed on a current collector. Similarly, the negative electrode may be a layer containing a negative electrode material formed on a current collector. Furthermore, since the electrolyte composition according to this disclosure contains an organic solvent, the adhesion between the electrodes (positive and negative electrodes) and the electrolyte can be improved. When assembling the battery, an organic solvent may be added between the electrodes and the electrolyte composition.

[0144] The battery according to this embodiment will be described below, using a lithium-ion battery as an example. For examples other than lithium-ion batteries, for example, the following description can be applied by replacing Li with an alkali metal element other than Li.

[0145] The positive electrode of the lithium-ion battery is not particularly limited and may include a positive electrode active material and, if necessary, a conductive additive, a binder, etc.

[0146] The positive electrode active material is not particularly limited and may be, for example, a lithium composite metal oxide 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.

[0147] The above lithium composite metal oxide is, for example, 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 (PO ４ ) ３ Li ２ CuO ２ Li ２ FeSiO ４ , and Li ２ MnSiO ４ That's fine.

[0148] The negative electrode of the lithium-ion battery is not particularly limited and may include a negative electrode active material and, if necessary, a conductive additive, a binder, etc.

[0149] The negative electrode active material may be, for example, 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, materials in which lithium ions are inserted between layers of the carbon material, and oxides containing titanium.

[0150] The positive electrode (positive electrode material) and negative electrode (negative electrode material) in this embodiment may further include an electrolyte material, a binding resin (binder), and a conductive additive.

[0151] The battery according to this embodiment may have a separator. The separator may be a porous material, or a porous resin material. Specific examples of porous materials include, for example, a porous polyolefin film and a porous ceramic film.

[0152] Although several embodiments have been described above, this disclosure is not limited in any way to the embodiments described above. Furthermore, the descriptions of the embodiments described above are applicable to each other.

[0153] The present disclosure will be described in more detail below with reference to examples and comparative examples. However, the present disclosure is not limited to the following examples.

[0154] <Synthesis of Monomer X> Monomer X, represented by the following formula, was synthesized by the following method.

[0155]

[0156] First, at 0°C, chlorosulfonic acid (69 mL, 1.04 mol) was added to N-phenylmaleimide (30 g, 0.17 mol), and the mixture was stirred at 45–50°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 filtered off, and the obtained crystals were purified by silica gel column chromatography. In this process, a mixture of hexane and ethyl acetate in a volume ratio of 1 / 2 to 1 / 1 was used as the eluent. As a result of the purification, 34 g (73% yield) of the intermediate represented by the following formula was obtained. The obtained intermediate was a slightly yellowish solid.

[0157]

[0158] 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, 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 sequentially, 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 removed from the filtrate under reduced pressure. The residue was decanted with diethyl ether and dried under reduced pressure, resulting in 10.5 g of monomer X as a slightly brown solid.

[0159] <Synthesis of Copolymer (Polymer (A))> 0.558 g of monomer X, 0.149 g of styrene, and 11.7 mg of azobisisobutyronitrile obtained as described above were dissolved in 6.7 mL of dehydrated acetonitrile. Tetralin was added as an internal standard, and the reaction was carried out at 60°C for 24 hours under a nitrogen atmosphere while checking 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, Mn, was calculated from 1H-NMR. Mn = 9.4 × 10⁻⁶ ４ , weight average molecular weight Mw=4.2×10 ５ The molecular weight distribution Mw / Mn was 4.45. The number-average molecular weight and weight-average molecular weight were measured by gel permeation chromatography.

[0160] (Example 1) [Production of Electrolyte Composition] First, a mixed solvent was prepared by mixing ethylene carbonate (EC) and propylene carbonate (PC) in a volume ratio of 1:1, and then adding fluoroethylene carbonate (FEC) to a mixture that was 5% by mass, and this was used as the organic solvent. Next, 100 parts by mass of the copolymer prepared as described above and 50 parts by mass of PVDF-HFP (poly(vinylidene fluoride-co-hexafluoropropylene)) as a fluororesin were mixed, and 450 parts by mass of the organic solvent was added to the mixture to prepare a gel-like composition.

[0161] The gel-like composition prepared as described above was mixed with fumed silica in an amount of 88.5% by volume and 11.5% by volume to prepare the electrolyte composition. Note that the BET (N) of the fumed silica was ２ BET(H) ２ The ratio of O) was 0.38, and the average particle size was 21 nm.

[0162] (Example 2) Instead of fumed silica, alumina particles A (BET(N) ２ BET(H) ２ An electrolyte composition was prepared in the same manner as in Example 1, except that alumina particles with an O ratio of 0.67 and an average particle size of 15 nm were used.

[0163] (Example 3) Instead of fumed silica, alumina particles B (BET(N) ２ BET(H) ２ An electrolyte composition was prepared in the same manner as in Example 1, except that alumina particles with an O ratio of 1.13 and an average particle diameter of 19 nm were used.

[0164] (Example 4) Instead of fumed silica, alumina particles C(BET(N) ２ BET(H) ２ An electrolyte composition was prepared in the same manner as in Example 1, except that alumina particles with an O ratio of 0.99 and an average particle diameter of 9 nm were used.

[0165] (Comparative Example 1) Instead of fumed silica, silica particles (BET(N) ２ BET(H)２ An electrolyte composition was prepared in the same manner as in Example 1, except that silica particles with an O ratio of 0.26 and an average particle diameter of 7 nm were used.

[0166] <Evaluation of Electrolyte Compositions> The ionic conductivity and activation energy of each electrolyte composition prepared in the examples and comparative examples were evaluated using the method shown below.

[0167] [Measurement of Ionic Conductivity] First, the inside of the glove box was adjusted to a dry argon atmosphere. Under this dry argon atmosphere, layers were stacked in the evaluation cell in the order of stainless steel plate, electrolyte composition, and stainless steel plate, thereby creating a test laminate (evaluation cell for coin-type battery CR2032) with a stainless steel plate / electrolyte composition / stainless steel plate laminate structure.

[0168] The impedance was measured using an impedance measuring device under the following conditions: 25°C, frequency range 0.1 Hz to 1 MHz, and applied voltage 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 sample area, and t represents the sample thickness. The results are shown in Table 1. σ (S・cm) －１ )=t(cm) / (R(Ω)×A(cm ２ ))

[0169] [Measurement of Activation Energy] Using a test laminate prepared in the same manner as the ionic conductivity measurement described above, ionic conductivity measurements were performed at 25°C, 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 the graph between the common logarithm of ionic conductivity and the reciprocal of temperature using the Arrhenius equation (log k = log A - Ea / RT, k: reaction rate constant, A: frequency factor, Ea: activation energy, R: gas constant, T: absolute temperature). The results are shown in Table 1.

[0170]

[0171] According to this disclosure, an electrolyte composition with excellent ionic conductivity can be provided.

Claims

1. The material comprises a polymer, inorganic particles, and an organic solvent, wherein the inorganic particles contain N as an adsorbent gas. ２ The specific surface area measured by the BET multipoint method using BET(N) is expressed as BET(N) ２ ) and H as the adsorbent gas ２ The specific surface area measured by the BET multipoint method using O is BET(H ２ When O), the BET(N ２ ) the BET(H ２ An electrolyte composition in which the ratio of O) is 0.30 or higher.

2. The electrolyte composition according to claim 1, wherein the inorganic particles include at least one selected from the group consisting of silica particles, alumina particles, and titania particles.

3. The electrolyte composition according to claim 1 or 2, further comprising metal ions.

4. The electrolyte composition according to claim 3, wherein the metal ions include alkali metal ions.

5. The electrolyte composition according to claim 1 or 2, wherein the polymer has an anionic group and an alkali metal ion as a countercation of the anionic group.

6. The electrolyte composition according to claim 1 or 2, wherein the polymer has at least one functional group selected from the group consisting of alkali metallated phenol group, alkali metallated carboxylic acid group, alkali metallated sulfonic acid group, alkali metallated carbonylsulfonylimide group, and alkali metallated sulfonylimide group.

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

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

9. An electrode comprising an electrolyte, wherein the electrolyte is the electrolyte composition described in claim 1 or 2.

10. A secondary battery comprising the electrode described in claim 9.

11. A secondary battery comprising an electrolyte containing the electrolyte composition described in claim 1 or 2.

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