Solid electrolytes and secondary batteries

Abstract

The purpose of the present disclosure is to provide a solid electrolyte medium and a composition for a solid electrolyte that make it possible to prepare a solid electrolyte which exhibits good ion conductivity and has high film strength, and further to provide a secondary battery that includes the solid electrolyte medium. Provided is a solid electrolyte medium that constitutes a solid electrolyte of an all solid state battery and comprises a polyurethane resin (U) which includes a structure derived from a polyol compound (A) and a structure derived from a polyisocyanate compound (B), wherein the polyol compound (A) includes a polyol compound (A1) having a PTME unit.

Description

[Technical Field]

[0001] The present disclosure relates to a solid electrolyte medium, a solid electrolyte composition, a secondary battery, and the like. [Background technology]

[0002] In recent years, there has been a strong desire to reduce carbon dioxide emissions in order to protect the environment. The automotive industry is hopeful that the introduction of electric vehicles (EVs), hybrid electric vehicles (HEVs), and other vehicles will help reduce carbon dioxide emissions, and efforts are being made to develop secondary batteries for motor drive, which hold the key to realizing these vehicles. Furthermore, with the development of portable devices such as personal computers and mobile phones, the demand for batteries as their power sources has increased significantly. Lithium-ion (secondary) batteries, which can achieve high energy density and high power density, are attracting attention as secondary batteries for use in such applications.

[0003] Most current lithium-ion secondary batteries use a liquid electrolyte, i.e., an electrolyte solution, in which a lithium electrolyte salt is dissolved in an electrolyte solvent primarily consisting of propylene carbonate, ethylene carbonate, etc. The electrolyte solution is an organic solvent-based electrolyte solution using an organic solvent as a medium, and batteries using such an electrolyte solution have safety issues, such as the risk of electrolyte leakage (leakage) and the risk of explosion, leakage, or fire due to an increase in internal pressure caused by a rise in temperature. Therefore, there has been active development into solidifying the electrolyte solution, i.e., solid electrolytes.

[0004] For example, Patent Document 1 proposes a polymer electrolyte composition containing a polyurethane resin (U) having a number average molecular weight of 1,000 to 500,000, obtained by reacting a polyether diol (A) having a number average molecular weight of 500 to 100,000 with an organic diisocyanate (B) as essential components, and a lithium salt. Patent Document 1 describes that a polymer electrolyte composition containing a polyurethane resin can achieve both high ionic conductivity at room temperature and cycle life characteristics.

[0005] Patent Document 2 proposes a polyurethane solid electrolyte comprising (A) a polyurethane containing, as a polyol component, (a) a polyalkylene carbonate polyol and / or (b) a polycarbonate polyurethane polyol obtained by reacting a polyalkylene carbonate polyol with a polyisocyanate, (B) an electrolyte salt, and (C) a nonaqueous organic solvent capable of dissolving the electrolyte salt. Patent Document 2 describes that polycarbonate-based polyurethane resins have high ionic conductivity and excellent mechanical strength.

[0006] However, in Patent Documents 1 and 2, it is necessary to use an organic solvent-based electrolyte solution in order to obtain high ionic conductivity, and the risk of fire remains unresolved.

[0007] To further improve safety, all-solid-state batteries using solid electrolytes that do not contain liquid electrolytes (electrolytic solutions) are also being developed. Patent Document 3 proposes a polymer electrolyte composition that does not use electrolytic solutions, and the polymer electrolyte composition contains a polymer of an acrylic monomer composition as the polymer. The polymer material used in Patent Document 3 is an acrylic material, and there is no mention of polyurethane materials. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-069388 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-076736 [Patent Document 3] Patent Publication No. 2021-118180 Summary of the Invention [Problem to be solved by the invention]

[0009] The solid electrolytes using resins described in Patent Documents 1 and 2 use an organic solvent-based electrolyte solution to obtain high ionic conductivity, and therefore still have the risk of battery ignition. Furthermore, in all-solid-state batteries that use solid electrolytes that do not contain an electrolytic solution, repeated charge and discharge can cause dendrites to grow from the negative electrode, which can come into contact with the positive electrode and cause a short circuit. Therefore, in order to put a solid electrolyte into practical use, it is necessary to have not only high ionic conductivity but also strength to prevent short circuits caused by dendrites.

[0010] The present disclosure aims to provide a solid electrolyte medium and a composition for a solid electrolyte, which can produce a solid electrolyte that exhibits good ionic conductivity and also has strong film strength, and further to provide a secondary battery having the solid electrolyte medium. [Means for solving the problem]

[0011] As a result of intensive research to solve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by a solid electrolyte medium constituting a solid electrolyte of an all-solid-state battery, the solid electrolyte medium containing a polyurethane resin (U) having a structure derived from a polyol compound (A) and a structure derived from a polyisocyanate compound (B), wherein the polyol compound (A) contains a polyol compound (A1) having a structural unit represented by the following formula (1) (hereinafter, also referred to as a PTME unit), and the degree of polymerization n of the PTME unit in the polyol compound (A1) having the PTME unit is 2 or more. The present disclosure has been completed as a result of further research based on these findings.

[0012] [ka] (wherein n is an integer of 2 or more).

[0013] That is, the present disclosure is as follows. [1] A solid electrolyte medium constituting a solid electrolyte of an all-solid-state battery, the solid electrolyte medium containing a polyurethane resin (U) including a structure derived from a polyol compound (A) and a structure derived from a polyisocyanate compound (B), wherein the polyol compound (A) includes a polyol compound (A1) having a structural unit represented by the following formula (1):

[0014] [ka] (wherein n is an integer of 2 or more).

[0015] [2] The solid electrolyte medium according to [1], wherein the polyol compound (A1) is polytetramethylene ether glycol or polyether polycarbonate diol. [3] The solid electrolyte medium according to [1] or [2], wherein the content of the polyol compound (A1) having the structural unit represented by the formula (1) in the polyol compound (A) is 1% by mass or more and 100% by mass or less. [4] The solid electrolyte medium according to any one of [1] to [3], wherein the content of the structural unit represented by formula (1) in the polyol compound (A1) having the structural unit represented by formula (1) is 80 mass % or more and 99.9 mass % or less. [5] The solid electrolyte medium according to any one of [2] to [4], wherein the polyol compound (A1) having the structural unit represented by the formula (1) is a polyether polycarbonate diol, and the content of the structural unit represented by the formula (1) in the polyol compound (A1) is 80 mass % or more and 99.9 mass % or less. [6] A solid electrolyte composition for an all-solid-state battery, comprising: a solid electrolyte medium containing a polyurethane resin (U) having a structure derived from a polyol compound (A) and a structure derived from a polyisocyanate compound (B); and a metal salt (C), wherein the polyol compound (A) comprises a polyol compound (A1) having a structural unit represented by the following formula (1):

[0016] [ka] (wherein n is an integer of 2 or more).

[0017] [7] The composition for solid electrolytes according to [6], wherein the weight ratio of the polyurethane resin (U) to the metal salt (C) in the composition for solid electrolytes is polyurethane resin / metal salt=20 / 80 to 95 / 5. [8] The solid electrolyte composition according to [6] or [7], wherein the metal salt (C) is an alkali metal salt. [9] The composition for solid electrolytes according to any one of [6] to [8], wherein the metal salt (C) is a lithium salt.

[10] A secondary battery comprising the solid electrolyte medium according to any one of [1] to [5]. [Effects of the Invention]

[0018] According to the present disclosure, a solid electrolyte medium and a composition for a solid electrolyte are provided that can produce a solid electrolyte that exhibits good ionic conductivity and also has strong film strength, and further a secondary battery having the solid electrolyte medium is provided. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present disclosure will be described in detail below.

[0020] solid electrolyte medium The electrolyte in a battery is a substance that transports charge carriers between the positive and negative electrodes. In the present disclosure, a solid electrolyte containing a metal salt as an electrolyte salt and a solid electrolyte medium, but not containing a liquid component such as an electrolytic solution, is used as the electrolyte. A battery containing such a solid electrolyte is an all-solid-state battery. Therefore, the solid electrolyte medium of the present disclosure constitutes the solid electrolyte of the all-solid-state battery.

[0021] The solid electrolyte medium of the present disclosure is a solid electrolyte medium constituting a solid electrolyte of an all-solid-state battery, which contains a polyurethane resin (U) including a structure derived from a polyol compound (A) and a structure derived from a polyisocyanate compound (B), and the polyol compound (A) includes a polyol compound (A1) having a PTME unit.

[0022] Polyurethane resin (U) Polyol compound (A) The polyol compound (A) includes a polyol compound having a PTME unit (hereinafter, also referred to as a "PTME unit-containing polyol compound") (A1). The PTME (polytetramethylene ether) unit is a structural unit represented by the following formula (1).

[0023] [ka]

[0024] n is usually an integer of 2 or more, preferably 2 or more and 139 or less, more preferably 5 or more and 70 or less, and particularly preferably 8 or more and 65 or less.

[0025] The PTME unit-containing polyol compound (A1) is not particularly limited, and examples thereof include polytetramethylene ether glycol, polyether polycarbonate diol, and the like.

[0026] The polytetramethylene ether glycol may be a commercially available product, such as PTMG250, PTMG650, PTMG850, PTMG1000, PTMG1300, PTMG1500, PTMG1800, PTMG2000, PTMG3000, or PTMG4000 manufactured by Mitsubishi Chemical Corporation. The polyether polycarbonate diol may be a commercially available product, such as PEPCD NT2006, PEPCD NT2002, or PEPCD NT1002 manufactured by Mitsubishi Chemical Corporation.

[0027] The PTME unit content in the PTME unit-containing polyol compound (A1) is preferably 80% by mass or more and 99.9% by mass or less.

[0028] The PTME unit-containing polyol compound (A1) is preferably polytetramethylene ether glycol or polyether polycarbonate diol.

[0029] When the PTME unit-containing polyol compound (A1) is polytetramethylene ether glycol, the PTME unit content is preferably 80% by mass or more and 99.9% by mass or less, more preferably 92% by mass or more and 99.8% by mass or less, and even more preferably 96% by mass or more and 99.6% by mass or less. When the PTME unit-containing polyol compound (A1) is a polyether polycarbonate diol, the PTME unit content is preferably 80% by mass or more and 99.9% by mass or less, more preferably 82% by mass or more and 98% by mass or less, and even more preferably 84% by mass or more and 96% by mass or less.

[0030] The average molecular weight of the PTME unit-containing polyol compound (A1) is not particularly limited, but is usually 150 or more, preferably 160 to 10,000, more preferably 400 to 5,000, even more preferably 600 to 4,700, and particularly preferably 1,500 to 3,500.

[0031] The molecular weight and degree of polymerization of the PTME unit contained in the polyurethane resin or polyether polycarbonate diol can be confirmed by the following method: 1 Examples include H-NMR measurement and GPC measurement. Polyurethane resin 1 For H-NMR measurement, the polyurethane resin, or components that have been decomposed or separated into constituent units by hydrolysis in advance, is dissolved in a deuterated solvent and measurement is performed, thereby enabling confirmation of the degree of polymerization of the PTME unit. In the hydrolysis method under basic conditions, 1 g of polyurethane resin is placed in a pressure decomposition vessel together with 20 mL of 20% aqueous sodium hydroxide solution and heated and decomposed at 160-180°C for 12 hours. After cooling, the mixture is extracted with chloroform, and 2N hydrochloric acid is added to the resulting organic layer 1, followed by separation. The resulting organic layer 2 is then used to obtain the polyether diol that constitutes the polyurethane resin. The resulting polyether diol is then added to the 1 Measure by H-NMR or GPC. Regarding GPC measurement, the molecular weight or degree of polymerization can be confirmed by measuring the polyether diol obtained by the hydrolysis method.

[0032] The polyol compound (A) may contain a polyol compound (A2) other than the PTME unit-containing polyol compound (A1).

[0033] The other polyol compound (A2) is not particularly limited as long as it is a compound having two or more hydroxyl groups (-OH) in one molecule. Examples of the other polyol compound (A2) include polyhydric alcohols, polyether polyols, polyester polyols, polyether ester polyols, polycarbonate polyols, polyacrylic polyols, polyacetal polyols, polybutadiene polyols, polysiloxane polyols, and fluorine polyols. The polyhydric alcohol is not particularly limited, and examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, polyoxyethylene glycol, 1,4-butanediol, propylene glycol, neopentyldiol, hexanediol, bisphenol A, bisphenol B, bisphenol S, hydrogenated bisphenol A, dibromobisphenol A, 1,4-cyclohexanedimethanol, dihydroxyethyl terephthalate, hydroquinone dihydroxyethyl ether, dimethylolpropionic acid, trimethylolpropane, glycerin, and pentaerythritol. The polyether polyol is not particularly limited, and examples of the polyether polyol include alkylene derivatives of polyhydric alcohols and polythioether polyols. The polyester polyol or polyether ester polyol is not particularly limited, and examples of the polyester polyol or polyether ester polyol include polyhydric alcohols, polycarboxylic acids, polycarboxylic anhydrides, polyether polyols, esters of polycarboxylic esters, castor oil polyols, polycaprolactone polyols, and polyalkylene carbonate diols. These may be used alone or in combination of two or more.

[0034] The content of the polyol compound (A1) having a PTME unit in the polyol compound (A) is preferably from 1% by mass to 100% by mass, more preferably from 50% by mass to 100% by mass, and even more preferably from 70% by mass to 99% by mass.

[0035] Monool Compound (D) The polyurethane resin may have a structure derived from a monool compound (D) in addition to the structure derived from the polyol compound (A). The monool compound (D) is a compound containing one hydroxyl group. Examples of the other monool compounds (D) include polyoxyethylene monomethyl ether, polyoxyethylene polyoxypropylene butyl ether, 2-hydroxyethyl methacrylate, and alcohols such as methanol, ethanol, isopropyl alcohol, and butanol. These may be used alone or in combination of two or more. When the monool compound (D) is contained, it is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of the polyol compound (A).

[0036] Polyisocyanate compound (B) The polyisocyanate compound (B) is a compound having two or more isocyanate groups (-NCO) in one molecule. Any polyisocyanate compound conventionally used in the production of polyurethanes can be used as the polyisocyanate compound (B) without any particular limitations. The polyisocyanate compound (B) includes, for example, organic polyisocyanate compounds such as aromatic polyisocyanates, araliphatic polyisocyanates, alicyclic polyisocyanates, and aliphatic polyisocyanates. The organic polyisocyanate compound may be a bifunctional compound, i.e., a compound having two isocyanate groups (-NCO) in one molecule, such as an aromatic diisocyanate, an araliphatic diisocyanate, an alicyclic diisocyanate, or an aliphatic diisocyanate. In addition, compounds having three or more functional groups, i.e., compounds having three or more isocyanate groups (-NCO) in one molecule, such as aromatic polyisocyanates, araliphatic polyisocyanates, alicyclic polyisocyanates, or aliphatic polyisocyanates, can be used. The polyisocyanate compound (B) may be used alone or in combination of two or more kinds.

[0037] Examples of the aromatic diisocyanate include m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4- or 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, and 4,4'-diphenyl ether diisocyanate.

[0038] Examples of the aromatic aliphatic diisocyanate include 1,3- or 1,4-xylylene diisocyanate, mixtures thereof, 1,3- or 1,4-bis(1-isocyanato-1-methylethyl)benzene, and mixtures thereof.

[0039] Examples of the alicyclic diisocyanate include 1,3-cyclopentene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, and 1,4-bis(isocyanatomethyl)cyclohexane.

[0040] Examples of the aliphatic diisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, and 2,6-diisocyanate methyl caproate.

[0041] Examples of the tri- or higher functional aromatic polyisocyanate include trifunctional aromatic polyisocyanates such as triphenylmethane-4,4',4"-triisocyanate, 1,3,5-triisocyanate benzene, and 2,4,6-triisocyanate toluene; and tetrafunctional aromatic polyisocyanates such as 4,4'-diphenylmethane-2,2',5,5'-tetraisocyanate.

[0042] Examples of the tri- or higher functional aromatic aliphatic polyisocyanate include trifunctional aromatic alicyclic polyisocyanates such as 1,3,5-triisocyanate methylbenzene.

[0043] Examples of the trifunctional or higher alicyclic polyisocyanate include 1,3,5-triisocyanate cyclohexane, 1,3,5-trimethylisocyanate cyclohexane, 2-(3-isocyanate propyl)-2,5-di(isocyanate methyl)bicyclo(2.2.1)heptane, 2-(3-isocyanate propyl)-2,6-di(isocyanate methyl)bicyclo(2.2.1)heptane, 3-(3-isocyanate propyl)-2,5-di(isocyanate methyl)bicyclo(2.2.1)heptane, 5-(2-isocyanate ethyl)bicyclo(2.2.1)heptane, )-2-isocyanatemethyl-3-(3-isocyanatepropyl)bicyclo(2.2.1)heptane, 6-(2-isocyanateethyl)-2-isocyanatemethyl-3-(3-isocyanatepropyl)bicyclo(2.2.1)heptane, 5-(2-isocyanateethyl)-2-isocyanatemethyl-2-(3-isocyanatepropyl)bicyclo(2.2.1)heptane, 6-(2-isocyanateethyl)-2-isocyanatemethyl-2-(3-isocyanatepropyl)bicyclo(2.2.1)heptane, etc.

[0044] Examples of the tri- or higher functional aliphatic polyisocyanates include trifunctional aliphatic polyisocyanates such as lysine ester triisocyanate, 1,4,8-triisocyanato octane, 1,6,11-triisocyanato undecane, 1,8-diisocyanato-4-isocyanato methyl octane, 1,3,6-triisocyanato hexane, and 2,5,7-trimethyl-1,8-diisocyanato-5-isocyanato methyl octane.

[0045] In addition to the above, derivatives of isocyanate compounds can also be used as polyisocyanates. Examples of such derivatives of isocyanate compounds include dimers, trimers, biuret, allophanates, carbodiimides, polymethylene polyphenyl polyisocyanates (crude MDI or polymeric MDI), crude TDI, and adducts of isocyanate compounds and low-molecular-weight polyols (e.g., trimethylolpropane).

[0046] The molar ratio of the hydroxyl groups in (A) and (D) to the isocyanate groups in (B) (R value: NCO groups / OH groups) is preferably 0.5-4, more preferably 0.8-3, and particularly preferably 0.9-2.

[0047] By using the solid electrolyte medium of the present disclosure, a solid electrolyte having good ionic conductivity and strong film strength can be obtained without using an organic solvent-based electrolyte solution.

[0048] Solid electrolyte composition for all-solid-state batteries In this specification, the solid electrolyte composition is a composition used for producing (molding) a solid electrolyte. When used in dry molding such as powder coating or injection molding, the composition may be in a (semi)solid state such as powder or paste. When used in wet forming such as coating or casting, the composition may be in a liquid state and become a solid electrolyte by drying or heating. The composition may contain a liquid medium such as water or an organic solvent as needed. Examples of solid electrolyte compositions used in the wet forming include coating liquids. Here, the solid electrolyte is used as an electrolyte for an all-solid-state battery. The solid electrolyte composition is a solid electrolyte medium containing a polyurethane resin (U) having a structure derived from a polyol compound (A) and a structure derived from a polyisocyanate compound (B); Metal salt (C) and A solid electrolyte composition for an all-solid-state battery, comprising: The polyol compound (A) includes a polyol compound (A1) having a PTME unit, The degree of polymerization n of the polyol compound (A1) having the PTME unit is 2 or more.

[0049] The solid electrolyte medium containing the polyurethane resin (U) of the present disclosure is in a solid state containing no liquid component when forming a solid electrolyte, but the properties when preparing the solid electrolyte composition vary depending on the molding method. In the case of a solid electrolyte composition for dry molding, it may be used in a (semi)solid state such as powder or paste. In the case of a solid electrolyte composition for wet molding, the polyurethane resin is preferably dispersed or dissolved in a liquid to facilitate molding, and therefore, the composition is preferably in the state of a liquid containing a polyurethane resin. The liquid material containing the polyurethane resin, which is a preferred embodiment of the solid electrolyte medium of the present disclosure, is not particularly limited as long as the liquid can be removed by drying. For example, an aqueous dispersion of the polyurethane resin (hereinafter sometimes referred to as an "aqueous dispersion-type polyurethane resin"), a solution of the polyurethane resin in a solvent (hereinafter sometimes referred to as a "solvent-type polyurethane resin"), etc. can be used.

[0050] The water-dispersible polyurethane resin can be produced by a known method. For example, the urethane prepolymer can be obtained by reacting a polyol compound (A), a polyisocyanate compound (B), and, if necessary, a hydrophilic group-containing compound, and, if necessary, neutralizing the contained hydrophilic groups or quaternizing them with a quaternizing agent to obtain a urethane prepolymer, emulsifying the urethane prepolymer with water, and then carrying out a chain extension reaction with water and / or a polyamine. When reacting the polyol compound (A) with the polyisocyanate compound (B), a solvent may be used as needed. Any organic solvent can be used as the solvent. Examples of the organic solvent include acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, ethyl acetate, and butyl acetate. The reaction conditions are, for example, 60°C to 80°C for about 2 to 4 hours, preferably about 70°C for about 3 hours, and if necessary, the reaction mixture can be cooled to 5°C to 45°C before the next step (neutralization or quaternization of the hydrophilic groups contained therein) can be carried out.

[0051] To promote the reaction, any known urethanization catalyst can be used without limitation, including, for example, inorganic metal catalysts, organometallic catalysts, and amine catalysts. Examples of the inorganic metal catalyst include inorganic tin catalysts and inorganic bismuth catalysts. Examples of the organometallic catalyst include an organotin catalyst, an organolead catalyst, and an organobismuth catalyst. Examples of the organotin catalyst include dioctyltin dilaurate, dibutyltin diacetate, dibutyltin dilaurate, and dioctyltin diacetate. Examples of the organic lead catalyst include lead octoate, lead octenoate, and lead naphthenate. Examples of the organic bismuth catalyst include bismuth octoate and bismuth neodecanoate. Examples of the amine catalyst include diethylenetriamine, triethylamine, and N,N-dimethylcyclohexylamine.

[0052] The molar equivalent ratio of isocyanate groups to hydroxyl groups used to obtain the urethane prepolymer is not particularly limited, as long as the ratio is isocyanate groups:hydroxyl groups=1.0 or more:1. The molar equivalent ratio is preferably 1.05 to 3:1, and more preferably 1.20 to 2.2:1, since this allows the urethane prepolymer to have a low viscosity and a stable emulsion to be obtained.

[0053] The hydrophilic group may be an anionic group, a cationic group, or a nonionic group. The hydrophilic group-containing compound for introducing the hydrophilic group is not particularly limited. Examples of the hydrophilic group-containing compound include neutralized products of (di)alkanolcarboxylic acids or sulfonic acids with tertiary amines or alkali metals, (methoxy)polyalkylene oxides, neutralized products of (di)alkanolamines with organic or inorganic acids, and quaternary ammonium salts obtained by reacting these with alkyl halide or dialkyl sulfate. Among these, neutralized products of (di)alkanolcarboxylic acids or sulfonic acids with tertiary amines or alkali metals, neutralized products of (di)alkanolamines with organic or inorganic acids, and quaternary ammonium salts obtained by reacting these with alkyl halide or dialkyl sulfate are preferred. The (methoxy)polyalkylene oxide should contain at least ethylene oxide as the alkylene oxide, and may also contain alkylene oxides other than ethylene oxide, such as propylene oxide and butylene oxide. When a (methoxy)polyalkylene oxide containing a plurality of types of alkylene oxides is used, the addition form (form of introduction of hydrophilic groups) may be either block addition or random addition.

[0054] Examples of compounds into which these hydrophilic groups can be introduced include the following. Examples of anionic types include salts obtained by neutralizing carboxylic acid compounds such as dimethylolpropionic acid, dimethylolbutanoic acid, lactic acid, and glycine, and sulfonic acid compounds such as polyester diols formed from aminoethylsulfonic acid and sulfoisophthalic acid and diols, with tertiary alkanolamines such as triethylamine, diisopropylethylamine, lithium hydroxide or its hydrate, sodium hydroxide, and dimethylaminoethanol. Of these, sodium salts of dimethylolpropionic acid, glycine, and aminoethylsulfonic acid are preferred. Examples of cationic types include salts obtained by neutralizing alkanolamines such as dimethylaminoethanol and methyldiethanolamine with organic carboxylic acids such as formic acid and acetic acid, or inorganic acids such as hydrochloric acid and sulfuric acid, or salts obtained by quaternizing alkanolamines with alkyl halides such as methyl chloride and methyl bromide, or dialkyl sulfates such as dimethyl sulfate, etc. Among these, the combination of methyldiethanolamine and an organic carboxylic acid and the combination of methyldiethanolamine and dimethyl sulfate are preferred because they can be easily produced industrially. The content of the hydrophilic group in the urethane prepolymer is not particularly limited, and is preferably 0.01 to 2.5 mmol / g, more preferably 0.02 to 1.8 mmol / g, and even more preferably 0.03 to 1.6 mmol / g.

[0055] The amount of water used for the emulsification is preferably about 100 to 900 parts by mass per 100 parts by mass of the urethane prepolymer.

[0056] A known chain extender can be used for the chain extension. Examples of the chain extender include water, ammonia, and polyamines. The polyamines are not particularly limited and include aliphatic polyamines such as ethylenediamine, trimethylenediamine, propylenediamine, diethylenetriamine, and triethylenetetramine; aromatic polyamines such as metaxylenediamine, tolylenediamine, and diaminodiphenylmethane; alicyclic polyamines such as piperazine and isophoronediamine; and polyhydrazides such as hydrazine and adipic acid dihydrazide. The chain extenders may be used alone or in combination of two or more. The chain extension conditions are, for example, about 40° C. to 60° C. for about 0.5 to 2 hours, preferably about 50° C. for about 1 hour.

[0057] The solid content of the polyurethane resin in the water-dispersible polyurethane resin is not particularly limited, and is, for example, preferably 1 to 60 mass %, more preferably 3 to 55 mass %, and even more preferably 4 to 50 mass %, based on the total amount of the water-dispersible polyurethane resin.

[0058] The solvent-based polyurethane resin can be produced by a known method. For example, the polyol compound (A1) containing PTME units and the polyisocyanate compound (B) are mixed in a solvent (medium) to react with each other, and then another polyol compound (A2) and / or a monool compound (D) are added and mixed in. The hydroxyl group-containing compound is added to consume the remaining isocyanate groups, and the reaction is continued until the concentration of the isocyanate groups reaches 0%. Any organic solvent can be used as the solvent, such as acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, N,N-dimethylacetamide, ethyl acetate, and butyl acetate. As the other polyol compound (A2) or monool compound (D), the above-mentioned compounds can be used, and examples thereof include 1,4-butanediol. The reaction conditions are, for example, usually about 20° C. to 150° C. for about 1 to 5 hours, preferably about 20° C. to 30° C. for about 2 to 4 hours. The conditions for the isocyanate group consumption step are, for example, about 40° C. to 60° C. for 12 hours or more. The solid content of the polyurethane resin in the solvent-based polyurethane resin is not particularly limited, and is, for example, preferably 1 to 60 mass %, more preferably 3 to 55 mass %, and even more preferably 4 to 50 mass %, based on the total amount of the solvent-based polyurethane resin.

[0059] The water-dispersible polyurethane resin or solvent-based polyurethane resin may contain various commonly used additives, as needed. Examples of such additives include weathering agents, antibacterial agents, antifungal agents, pigments, inorganic fillers, organic fillers, rust inhibitors, dyes, film-forming aids, inorganic crosslinking agents, organic crosslinking agents (e.g., blocked isocyanate crosslinking agents, epoxy crosslinking agents, carbodiimide crosslinking agents, oxazoline crosslinking agents, melamine crosslinking agents, etc.), silane coupling agents, antiblocking agents, viscosity modifiers, leveling agents, antifoaming agents, dispersion stabilizers, light stabilizers, antioxidants, ultraviolet absorbers, plasticizers, lubricants, and antistatic agents.

[0060] The acid value of the water-dispersible polyurethane resin or solvent-based polyurethane resin is preferably in the range of 0 to 50 mgKOH / g, more preferably in the range of 5 to 40 mgKOH / g. The acid value is a value obtained by titrating a polyurethane resin having carboxy groups dissolved in an appropriate solvent with an alkali such as potassium hydroxide, and serves as an index of the carboxy group content. The acid value can also be calculated from the amounts of raw materials used in the synthesis of the polyurethane resin.

[0061] Metal salts (C) In the present disclosure, any metal salt that has been conventionally used as an electrolyte salt in batteries can be used, including, for example, alkali metal salts such as lithium salts, sodium salts, and potassium salts. Specific examples of lithium salts include LiBr, LiCl, LiI, LiSCN, LiBF4, LiAsF6, LiClO4, CH3COOLi, CF3COOLi, LiCF3SO3, LiPF6, and LiN(CF3SO2)2. Specific examples of sodium salts include NaBr, NaCl, NaI, NaSCN, NaBF4, NaAsF6, NaClO4, CH3COONa, CF3COONa, NaCF3SO3, NaPF6, and NaN(CF3SO2)2. Specific examples of potassium salts include KBr, KCl, KI, KSCN, KBF4, KAsF6, KClO4, CH3COOK, CF3COOK, KCF3SO3, KPF6, and KN(CF3SO2)2. The metal salts may be used alone or in combination of two or more kinds. The metal salt is preferably a lithium salt.

[0062] The content of the polyurethane resin (U) in the composition for solid electrolyte is preferably 1 to 80 mass %, more preferably 5 to 60 mass %, based on the mass of the composition for solid electrolyte.

[0063] The weight ratio of the polyurethane resin (U) to the metal salt (C) in the solid electrolyte composition is preferably polyurethane resin (U) / metal salt (C)=5 / 95 to 95 / 5, more preferably 10 / 90 to 70 / 30.

[0064] The solid electrolyte composition of the present disclosure may further contain additives such as plasticizers, stabilizers, antioxidants, and release agents that are used in known polymer compounds, within a range that does not contradict the object of the present disclosure.

[0065] The method for producing the solid electrolyte composition of the present disclosure is not particularly limited. For example, the solid electrolyte composition can be obtained by mixing the water-dispersible polyurethane resin or the solvent-based polyurethane resin, which is a solid electrolyte medium, and the metal salt in a predetermined ratio. The mixing can be carried out by a conventionally known method, for example, using a mixer such as a homomixer, homodisper, wave rotor, homogenizer, disperser, paint conditioner, ball mill, magnetic stirrer, or mechanical stirrer.

[0066] The solid electrolyte composition of the present disclosure is suitable for use in molding a solid electrolyte. A solid electrolyte molded body obtained by dry molding or wet molding using the solid electrolyte composition can have various forms depending on the intended use. Examples of the form include a membrane, a plate, a fiber, a hollow fiber, a particle, a block, a microporous form, a foam, and the like.

[0067] solid electrolyte A solid electrolyte obtained by wet molding using a liquid solid electrolyte composition containing a liquid medium such as water or an organic solvent is obtained by drying the solid electrolyte composition. By drying the solid electrolyte composition, the liquid medium contained in the solid electrolyte composition is removed, resulting in a solid electrolyte containing a metal salt and a polyurethane resin, which is the solid content of the solid electrolyte medium. It is desirable to remove all of the liquid medium contained in the solid electrolyte composition by drying during molding of the solid electrolyte. However, it is acceptable for some of the liquid medium to remain in the solid electrolyte to the extent that it does not pose safety issues, such as the risk of electrolyte leakage (leakage) in the battery, or the risk of leakage, explosion, or fire due to an increase in internal pressure when the temperature rises (less than 1% by mass of the electrolyte). The drying temperature and drying time are not particularly limited as long as the water or solvent contained in the solid electrolyte composition is substantially removed. The drying temperature is, for example, usually 40°C or higher, preferably 50°C to 110°C. Drying at a low temperature (about 50°C) may be performed first, followed by drying at a high temperature (about 110°C). The drying time is, for example, 24 hours or more, preferably 24 to 30 hours. The water content in the solid electrolyte can be confirmed, for example, by Karl Fischer moisture content measurement (vaporization method). In this method, the moisture in the solid electrolyte is vaporized using a moisture vaporizer, and the vaporized moisture is introduced into a titration cell using a carrier gas (nitrogen, etc.), allowing the moisture content to be measured. (Apparatus used: Metrohm 899 coulometer (with one-liquid electrode), 866KF Thermoprep (resistance temperature detector temperature control unit)) The solvent content in the solid electrolyte can be confirmed, for example, by headspace gas chromatography (HS-GC). In this method, the solvent in the solid electrolyte is vaporized in a headspace unit, and the vaporized solvent is injected into a packed column using a carrier gas (hydrogen, helium, etc.), allowing the amount of solvent to be measured. (Apparatus used: Shimadzu Corporation GC-14A (gas chromatography), AOC-14 AUTO INJECTOR (headspace unit))

[0068] The ionic conductivity of the solid electrolyte is usually 0.1 μS / cm or more, preferably 0.5 μS / cm or more, and more preferably 1 μS / cm or more.

[0069] The puncture strength of the solid electrolyte is usually 30 cN or more, preferably 40 cN or more, and more preferably 50 cN or more.

[0070] secondary battery The present disclosure encompasses a secondary battery having the solid electrolyte medium. The secondary battery is not particularly limited as long as it includes the solid electrolyte medium, and other configurations, structures, etc. of the secondary battery may be conventionally known. The secondary battery of the present disclosure is, for example, an all-solid-state battery containing a solid electrolyte containing the solid electrolyte medium and a metal salt between a positive electrode and a negative electrode, and in the secondary battery of the present disclosure, metal ions are conducted between the positive electrode and the negative electrode via the solid electrolyte medium. The secondary battery of the present disclosure can be obtained by, for example, stacking a positive electrode, the solid electrolyte, and a negative electrode in a battery outer container (such as a laminate container), and sealing the battery outer container with a current extraction terminal connected to a current collector protruding outside the container.

[0071] In the secondary battery of the present disclosure, the solid electrolyte composition may be formed into a film and used as the solid electrolyte. [Example]

[0072] The present disclosure will be explained in more detail below using examples, but the technical scope of the present disclosure is not limited to these examples.

[0073] Ingredients Production of solid electrolyte media (Production Examples 1 to 19 and Comparative Production Examples 1 to 3) PTME unit-containing polyol compound (A1) PEPCD NT2002: Polyether polycarbonate diol, average molecular weight 2000, PTME unit content 83.9% by mass, degree of polymerization of PTME units n=2.9, manufactured by Mitsubishi Chemical Corporation PEPCD NT2006: Polyether polycarbonate diol, average molecular weight 2000, PTME unit content 94.7% by mass, degree of polymerization of PTME units n=8.8, manufactured by Mitsubishi Chemical Corporation PTMG2000: Polytetramethylene ether glycol, average molecular weight 2000, PTME unit content 99.1% by mass, degree of polymerization of PTME unit n=27.5, manufactured by Mitsubishi Chemical Corporation PTMG3000: Polytetramethylene ether glycol, average molecular weight 3000, PTME unit content 99.4% by mass, degree of polymerization of PTME unit n=41.4, manufactured by Mitsubishi Chemical Corporation PTMG4000: Polytetramethylene ether glycol, average molecular weight 4000, PTME unit content 99.6% by mass, degree of polymerization of PTME unit n=55.3, manufactured by Mitsubishi Chemical Corporation

[0074] Other polyol compounds (A2) PEG#2000: Polyoxyethylene glycol, average molecular weight 2000, manufactured by Sanyo Chemical Industries, Ltd. Duranol (registered trademark) T6002: Polyalkylene carbonate diol, average molecular weight 2000, manufactured by Asahi Kasei Chemicals Corporation TEGOMER D3403: Methoxypolyethylene oxide trimethylolpropane ether, average molecular weight 1200, manufactured by Evonik Bis-MPA: Dimethylolpropionic acid, manufactured by Perstorp 1,4-Butanediol: Mitsubishi Chemical Corporation Trimethylolpropane: Perstorp Neopentyl glycol: Mitsubishi Gas Chemical Company, Inc. Monool Compound (D) Uniox (registered trademark) M-2000: Polyoxyethylene monomethyl ether, average molecular weight 2000, manufactured by NOF Corporation Unilube (registered trademark) 50MB-26: Polyoxyethylene polyoxypropylene butyl ether, average molecular weight 1800, manufactured by NOF Corporation 2-Hydroxyethyl methacrylate: Tokyo Chemical Industry Co., Ltd.

[0075] Polyisocyanate compound (B) Desmodur (registered trademark) W: methylenebis(1,4-cyclohexanediyl)bisisocyanate, manufactured by Covestro VESTANAT® IPDI: 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, manufactured by Evonik Takenate (registered trademark) 500: Xylylene diisocyanate, manufactured by Mitsui Chemicals, Inc. Duranate (registered trademark) 50M, hexamethylene diisocyanate, manufactured by Asahi Kasei Chemicals Corporation Millionate (registered trademark) MT: Diphenylmethane diisocyanate, manufactured by Tosoh Corporation

[0076] Chain extender Ethylenediamine: manufactured by Tokyo Chemical Industry Co., Ltd. Diethylenetriamine: manufactured by Tokyo Chemical Industry Co., Ltd.

[0077] Neutralizer Diisopropylethylamine: manufactured by Koei Chemical Co., Ltd. Triethylamine: manufactured by Tokyo Chemical Industry Co., Ltd. Lithium hydroxide monohydrate: manufactured by Tokyo Chemical Industry Co., Ltd.

[0078] catalyst Neostan (registered trademark) U-600: Bismuth catalyst, manufactured by Nitto Kasei Co., Ltd.

[0079] Preparation of Solid Electrolytes (Examples 1 to 22 and Comparative Examples 1 to 4) metal salts LiTFSI: Lithium bis(trifluoromethanesulfonyl)imide, manufactured by Tokyo Chemical Industry Co., Ltd. NaTFSI: Sodium bis(trifluoromethanesulfonyl)imide, manufactured by Tokyo Chemical Industry Co., Ltd. solid electrolyte medium Water-dispersible polyurethane resins or solvent-based polyurethane resins of Production Examples 1 to 19, and water-dispersible polyurethane resins of Comparative Production Examples 2 to 3 Alcox (registered trademark) L-11: polyethylene oxide, manufactured by Meisei Chemical Industry Co., Ltd.

[0080] Example of solid electrolyte medium production Manufacturing Example 1 A separable flask equipped with a stirrer, a condenser, and a thermometer was charged with 16.5 parts by mass of Desmodur (registered trademark) W and 14.0 parts by mass of VESTANAT (registered trademark) IPDI as the polyisocyanate compound (B), 61.3 parts by mass of PTMG2000 (average molecular weight 2000) as the PTME unit-containing polyol compound (A1), 0.8 parts by mass of neopentyl glycol and 7.3 parts by mass of Bis-MPA as other polyol compounds (A2), 6.7 parts by mass of diisopropylethylamine as a neutralizing agent, and 103.5 parts by mass of methyl ethyl ketone as an organic solvent, and mixed at room temperature. Next, the liquid temperature was raised to 70°C, and 0.07 parts by mass of Neostan U-600 catalyst was added. The reaction was continued until the isocyanate group concentration (content) of the reaction liquid, measured according to Method A of JIS K 1603-1:2007, reached 2.60%. After cooling the liquid temperature to 30°C, 181 parts by mass of ion-exchanged water was added dropwise under vigorous stirring to disperse the mixture. To the resulting dispersion, an aqueous solution of 0.03 parts by mass of ethylenediamine and 1.1 parts by mass of diethylenetriamine, a chain extender, dissolved in 71.0 parts by mass of ion-exchanged water, was added, and the mixture was allowed to react for 1 hour at a liquid temperature of 50°C. Subsequently, methyl ethyl ketone was distilled off under reduced pressure, and ion-exchanged water was added to obtain a water-dispersible polyurethane resin with a solids content of 30%.

[0081] Production Examples 2 to 17 and Comparative Production Examples 1 to 3 A water-dispersible polyurethane resin was obtained using the composition and contents shown in Table 1 by the method described in Production Example 1. In Comparative Production Example 1, it was not possible to produce a polyurethane resin.

[0082] Manufacturing Example 18 A separable flask equipped with a stirrer, condenser, and thermometer was charged with 12.5 parts by weight of Millionate (registered trademark) MT as the polyisocyanate compound (B), 60.0 parts by weight of PTMG2000 (average molecular weight 2000) as the PTME unit-containing polyol compound (A1), and 108.0 parts by weight of N,N-dimethylacetamide as an organic solvent, and mixed at room temperature. The reaction was continued until the isocyanate group concentration (content) of the reaction solution measured in accordance with Method A of JIS K 1603-1:2007 reached 1.80%. A solution of 0.90 parts by weight of 1,4-butanediol in 185.0 parts by weight of N,N-dimethylacetamide as another polyol compound (A2) was added, and the mixture was allowed to react at a liquid temperature of 30°C for 1 hour. Thereafter, the reaction was continued until the concentration of isocyanate groups reached 0.00%, and N,N-dimethylacetamide was added to obtain a solvent-based polyurethane resin with a solid content of 20%.

[0083] Manufacturing Example 19 A solvent-based polyurethane resin was obtained using the composition and contents shown in Table 1 by the method described in Production Example 18.

[0084] [Table 1] JPEG0007827346000006.jpg247170JPEG0007827346000007.jpg219170

[0085] Example: Solid electrolyte using lithium salt Example 1 A solid electrolyte composition was produced by mixing the water-dispersible polyurethane resin obtained in Production Example 1 and a metal salt (LiTFSI) so that the metal salt (LiTFSI) in the solid electrolyte was in the proportion shown in Table 2. The obtained solid electrolyte composition was dried at 50°C for 24 hours and then at 110°C for 1 hour to produce a solid electrolyte. The ionic conductivity and puncture strength of the obtained solid electrolyte were measured by the following methods.

[0086] Ionic conductivity measurement The ionic conductivity of the resulting solid electrolyte was measured using an impedance measuring device. Film production conditions: 50℃ x 24 hours + 110℃ x 1 hour Test sample: φ5.0mm x 0.39mm Measurement temperature: 24℃ Measuring equipment: Hokuto Denko HZ-5000 HAG3001 Measurement conditions: 10mV, 10Hz to 0.1MHz

[0087] Film puncture test The value of the scale (average value of 3 tests) at the moment when the film was broken through was measured for the obtained solid electrolyte (film thickness 30 μm) using a rod-type tension gauge with a needle (manufactured by Nakamura Seisakusho, model number TK10000CN-G). Test surface: φ16mm, piercing rod diameter: φ3mm

[0088] Examples 2 to 19 The water-dispersible polyurethane resins or solvent-based polyurethane resins obtained in Production Examples 2 to 19 and a metal salt (LiTFSI) were mixed so that the metal salt (LiTFSI) in the solid electrolyte was in a ratio shown in Table 2, and solid electrolyte compositions were produced in the same manner as in Example 1. Each solid electrolyte was then dried in the same manner as in Example 1. The ionic conductivity and puncture strength of each of the obtained solid electrolytes were measured.

[0089] Comparative Example 1 The water-dispersible polyurethane resin obtained in Comparative Production Example 2 and a metal salt (LiTFSI) were mixed so that the metal salt (LiTFSI) content in the solid electrolyte was as shown in Table 2, and a solid electrolyte composition was produced in the same manner as in Example 1. The solid electrolyte was dried in the same manner as in Example 1 to produce a solid electrolyte. The ionic conductivity and puncture strength of the obtained solid electrolyte were measured.

[0090] Comparative Example 2 The water-dispersible polyurethane resin obtained in Comparative Production Example 3 and a metal salt (LiTFSI) were mixed so that the metal salt (LiTFSI) in the solid electrolyte was in a ratio shown in Table 2, and a solid electrolyte composition was produced in the same manner as in Example 1, and the solid electrolyte was produced by drying in the same manner as in Example 1. The ionic conductivity and puncture strength of the obtained solid electrolyte were measured.

[0091] Comparative Example 3 A solid electrolyte composition was obtained by using polyethylene oxide (ALKOX (registered trademark) L-11) instead of the water-dispersible polyurethane resin and dissolving it in water so that the metal salt (LiTFSI) in the solid electrolyte was in the proportion shown in Table 2. Drying was carried out in the same manner as in Example 1 to produce a solid electrolyte. The ionic conductivity and puncture strength of the obtained solid electrolyte were measured.

[0092] [Table 2] JPEG0007827346000009.jpg25574

[0093] Example: Solid electrolyte using sodium salt Example 20 The water-dispersible polyurethane resin obtained in Production Example 5 and a metal salt (NaTFSI) were mixed so that the metal salt (NaTFSI) in the solid electrolyte was in a ratio shown in Table 3, and a solid electrolyte composition was produced in the same manner as in Example 1, and then dried in the same manner as in Example 1 to produce a solid electrolyte. The ionic conductivity and puncture strength of the obtained solid electrolyte were measured.

[0094] Comparative Example 4 The water-dispersible polyurethane resin obtained in Comparative Production Example 3 and a metal salt (NaTFSI) were mixed so that the metal salt (NaTFSI) in the solid electrolyte was in a ratio shown in Table 3, and a solid electrolyte composition was produced in the same manner as in Example 1, and then dried in the same manner as in Example 1 to produce a solid electrolyte. The ionic conductivity and puncture strength of the obtained solid electrolyte were measured.

[0095] [Table 3]

[0096] Example: Solid electrolyte containing high concentration of metal salt Example 21 The water-dispersible polyurethane resin obtained in Production Example 5 and a metal salt (LiTFSI) were mixed so that the metal salt (LiTFSI) in the solid electrolyte was in a ratio shown in Table 4, and a solid electrolyte composition was produced in the same manner as in Example 1, and then dried in the same manner as in Example 1 to produce a solid electrolyte. The ionic conductivity and puncture strength of the obtained solid electrolyte were measured.

[0097] Example 22 The water-dispersible polyurethane resin obtained in Production Example 5 and a metal salt (NaTFSI) were mixed so that the metal salt (NaTFSI) in the solid electrolyte was in a ratio shown in Table 4, and a solid electrolyte composition was produced in the same manner as in Example 1, and then dried in the same manner as in Example 1 to produce a solid electrolyte. The ionic conductivity and puncture strength of the obtained solid electrolyte were measured.

[0098] [Table 4] [Industrial Applicability]

[0099] The solid electrolyte medium of the present disclosure and the secondary battery using the same are useful for mobile phones, personal computers, hybrid vehicles, and electric vehicles. This application claims priority from Japanese Patent Application No. 2023-205957, filed December 6, 2023. Japanese Patent Application No. 2023-205957 is incorporated herein by reference.

Claims

1. A solid electrolyte for an all-solid-state battery, comprising: The content of the liquid medium in the solid electrolyte is less than 1 mass %, Contains a polyurethane resin (U) and a metal salt (C), The polyurethane resin (U) is a structure derived from the polyol compound (A); A structure derived from the polyisocyanate compound (B), Including, The polyol compound (A) contains polytetramethylene ether glycol (A1), the content of polytetramethylene ether glycol (A1) in the polyol compound (A) is 70% by mass or more and 99% by mass or less; solid electrolyte.

2. The solid electrolyte according to claim 1 , wherein the polyisocyanate compound (B) includes an alicyclic diisocyanate.

3. The solid electrolyte according to claim 1 , wherein the polyol compound (A) further contains a polyol compound (A2) other than a polyol compound having a structural unit represented by formula (1). 【Chemistry 1】 (In the formula, n is an integer of 2 or more.)

4. The solid electrolyte according to claim 1 , wherein the polyurethane resin (U) further includes a structure derived from a chain extender.

5. A solid electrolyte as described in claim 1, wherein the weight ratio of polyurethane resin (U) to metal salt (C) in the solid electrolyte is polyurethane resin / metal salt = 20 / 80 to 95 / 5.

6. The solid electrolyte of claim 1, wherein the metal salt (C) is an alkali metal salt.

7. The solid electrolyte of claim 1, wherein the metal salt (C) is a lithium salt.

8. A secondary battery having the solid electrolyte of claim 1.

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