Composition, mixture for electrochemical device, mixture sheet for electrochemical device, electrochemical device, and method for manufacturing mixture sheet for electrochemical device

Abstract

The purpose of the present disclosure is to provide: a composition capable of reducing the resistance of an electrochemical device having a sulfide solid electrolyte; a mixture for an electrochemical device; a mixture sheet for an electrochemical device; an electrochemical device; and a method for manufacturing a mixture sheet for an electrochemical device. Disclosed herein is a composition comprising a sulfide solid electrolyte, a fluoropolyether, and a fibrillar resin.

Description

Composition, mixture for electrochemical device, mixture sheet for electrochemical device, electrochemical device, and method for manufacturing mixture sheet for electrochemical device

[0001] The present disclosure relates to a composition, a mixture for an electrochemical device, a mixture sheet for an electrochemical device, an electrochemical device, and a method for producing a mixture sheet for an electrochemical device.

[0002] BACKGROUND ART With the recent trend toward lighter and smaller electrical appliances, the development of electrochemical devices such as lithium ion secondary batteries with high energy density has been progressing.

[0003] As technologies relating to electrochemical devices, Patent Document 1 discloses a solid electrolyte composition containing a specific (per)fluoropolyether, a specific poly(alkylene) oxide, and a lithium salt, and Patent Document 2 discloses a solid electrolyte slurry containing an inorganic solid electrolyte material and a liquid such as perfluoropolyether or silicone oil, and in which the content of a binder resin is adjusted to fall within a specific range.

[0004] JP 2022-506854 A JP 2016-062709 A

[0005] When manufacturing electrochemical devices such as secondary batteries, it is believed that pressing electrodes and other components at high pressure reduces the resistance of the electrodes and other components. The resistance-reducing effect of high-pressure pressing is particularly pronounced when manufacturing electrochemical devices having a sulfide solid electrolyte. On the other hand, to simplify the manufacturing process of electrochemical devices and reduce manufacturing costs, it is desirable to press electrodes and other components at low pressure. However, when low-pressure pressing is used to manufacture electrochemical devices having a sulfide solid electrolyte, it tends to be difficult to achieve the above-mentioned resistance-reducing effect. Therefore, a new technology is needed to reduce the resistance of electrochemical devices having a sulfide solid electrolyte.

[0006] An object of the present disclosure is to solve the above-mentioned problems and to provide a composition that can reduce the resistance of an electrochemical device having a sulfide solid electrolyte, a mixture for electrochemical devices, a mixture sheet for electrochemical devices, an electrochemical device, and a method for manufacturing a mixture sheet for electrochemical devices.

[0007] The present disclosure (1) is a composition comprising a sulfide solid electrolyte, a fluoropolyether, and a fibrillar resin.

[0008] The present disclosure (2) is the composition according to the present disclosure (1), wherein the fluoropolyether is at least one of the fluoropolyethers represented by the following formulas (1) to (4): (1) R １ -O-Ra １ -Rb １ -O-Ra １ -R １ (2) R ２ -Rb ２ -O-Ra ２ -Rb ２ -R ２ (3) R ３ -Rb ３ -O-Ra ３ -R ３ (4) R ４ -Rb ４ -R ４ (In the formula, Ra １ ~Ra ３ are each independently a group containing a fluorine-free alkylene unit and / or a fluorine-free oxyalkylene unit, １ ~Ra ３ Each oxyalkylene unit is independently —CH ２ CH ２ O- or -CH ２ CH(J)O—, each J is independently an alkyl group or an aryl group, and Rb １ ~Rb ４ are each independently a fluoropolyether group represented by the following formula (5), １ ~R ３ are each independently a hydrogen atom, a hydroxyl group, a fluorine atom, an alkyl group having 1 to 3 carbon atoms, an aryl group, a carboxylic acid group, or a fluoroalkyl group having 1 to 3 carbon atoms, ４ are each independently a fluorine atom, a hydrogen atom, a hydroxyl group, an aldehyde group, a carboxylic acid group, an alkyl ester group having 1 to 10 carbon atoms, an amide group which may have a substituent, or an amino group which may have a substituent. １ -Rf-O-Rf ２ - (wherein, Rf１ and Rf ２ are each independently an alkylene group having 1 to 16 carbon atoms which may be substituted with a fluorine atom, and Rf is a divalent fluoropolyether group.

[0009] The present disclosure (3) is １ ~Ra ３ are each independently a polyoxyalkylene group represented by the following formula (Ra-I): (Ra-I): —(CH ２ CH ２ O)r-(CH ２ CH (CH ３ )O)s-(CH ２ CH (CH ２ CH ３ )O)t-(CH ２ CH(Ph)O)u- (wherein r, s, t, and u each independently represent an integer of 0 or 1 or greater, and r+s+t+u is 4 to 50.)

[0010] The present disclosure (4) is １ ~Ra ３ The composition according to the present disclosure (2) or (3), wherein the number average molecular weight of

[0011] The present disclosure (5) is the composition according to any one of the present disclosures (2) to (4), wherein each Rf is independently a fluoropolyether group represented by the following formula (Rf-I): Formula (Rf-I): -(OC ６ F １２ ) a-(OC ５ F １０ ) b-(OC ４ F ８ ) c-(OC ３ Rc ６ ) d-(OC ２ F ４ ) e-(OCF ２)f- (In the formula, each Rc is independently a hydrogen atom, a fluorine atom, or a chlorine atom; each a, b, c, d, e, and f is independently an integer of 0 to 200; the sum of a, b, c, d, e, and f is 1 or more; the order of the repeating units assigned with a, b, c, d, e, or f is arbitrary; and when all Rc's are hydrogen atoms or chlorine atoms, at least one of a, b, c, e, and f is 1 or more.)

[0012] The present disclosure (6) is the composition according to any one of the present disclosures (2) to (5), wherein each Rf is independently a group represented by the following formula (Rf-II) or the following formula (Rf-I-II): Formula (Rf-II): -(OC ３ F ６ ) d-(OC ２ F ４ )e- (wherein d is an integer of 1 to 200, and e is 0 or 1) Formula (Rf-I-II): -(OC ４ F ８ ) c-(OC ３ F ６ ) d-(OC ２ F ４ ) e-(OCF ２ )f- (In the formula, c and d each independently represent an integer of 0 to 30, e and f each independently represent an integer of 1 to 200, the sum of c, d, e and f is 2 or more, and the order of the repeating units assigned with c, d, e or f is arbitrary.)

[0013] The present disclosure (7) is １ ~R ３ are each independently a methyl group, an ethyl group, a trifluoromethyl group, or a pentafluoroethyl group.

[0014] The present disclosure (8) is the composition according to any one of the present disclosures (1) to (7), wherein the fibrillar resin is polytetrafluoroethylene.

[0015] The present disclosure (9) is the composition according to any one of the present disclosures (1) to (8), wherein the fluoropolyether is liquid at any temperature between 25°C and 80°C.

[0016] The present disclosure (10) is the composition according to any one of the present disclosures (1) to (9), in which the content of the polyalkylene oxide represented by the following formula (6) is less than 20 mass %. (6) R １Ｂ -(OCHR １Ａ (CH ２ ) jCHR ２Ａ ) n-OR ２Ｂ (In the formula, R １Ａ and R ２Ａ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, j is an integer of 0 or 1 or 2, and R １Ｂ and R ２Ｂ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and n is an integer of 5 to 1000.

[0017] The present disclosure (11) is the composition according to any one of the present disclosures (1) to (10), wherein the content of the lithium salt relative to the fluoropolyether is 0.1 to 30% by mass.

[0018] The present disclosure (12) is a mixture for electrochemical devices, comprising the composition according to any one of the present disclosures (1) to (11).

[0019] The present disclosure (13) is the mixture for electrochemical devices according to the present disclosure (12), which contains a conductive assistant.

[0020] The present disclosure (14) is a mixture sheet for electrochemical devices, comprising the mixture for electrochemical devices according to the present disclosure (12) or (13).

[0021] The present disclosure (15) is an electrochemical device using the mixture sheet for an electrochemical device according to the present disclosure (14).

[0022] The present disclosure (16) is a method for producing a composite sheet for an electrochemical device, the method comprising: a step (1) of mixing a fluoropolyether, a fibrillar resin, and a sulfide solid electrolyte; and a step (2) of rolling the composition obtained in the step (1) into a sheet.

[0023] The present disclosure (17) is the manufacturing method according to the present disclosure (16), wherein the fluoropolyether is at least one of the following formulas (1) to (4), and the fibrillar resin is polytetrafluoroethylene.１ -O-Ra １ -Rb １ -O-Ra １ -R １ (2) R ２ -Rb ２ -O-Ra ２ -Rb ２ -R ２ (3) R ３ -Rb ３ -O-Ra ３ -R ３ (4) R ４ -Rb ４ -R ４ (In the formula, Ra １ ~Ra ３ are each independently a group containing a fluorine-free alkylene unit and / or a fluorine-free oxyalkylene unit, １ ~Ra ３ Each oxyalkylene unit is independently —CH ２ CH ２ O- or -CH ２ CH(J)O—, each J is independently an alkyl group or an aryl group, and Rb １ ~Rb ４ are each independently a fluoropolyether group represented by the following formula (5), １ ~R ３ are each independently a hydrogen atom, a hydroxyl group, a fluorine atom, an alkyl group having 1 to 3 carbon atoms, an aryl group, a carboxylic acid group, or a fluoroalkyl group having 1 to 3 carbon atoms, ４ are each independently a fluorine atom, a hydrogen atom, a hydroxyl group, an aldehyde group, a carboxylic acid group, an alkyl ester group having 1 to 10 carbon atoms, an amide group which may have a substituent, or an amino group which may have a substituent. １ -Rf-O-Rf ２ - (wherein, Rf １ and Rf ２ are each independently an alkylene group having 1 to 16 carbon atoms which may be substituted with a fluorine atom, and Rf is each independently a group represented by the following formula (Rf-II) or (Rf-I-II). Formula (Rf-II): -(OC ３F ６ ) d-(OC ２ F ４ )e- (wherein d is an integer of 1 to 200, and e is 0 or 1) Formula (Rf-I-II): -(OC ４ F ８ ) c-(OC ３ F ６ ) d-(OC ２ F ４ ) e-(OCF ２ )f- (In the formula, c and d each independently represent an integer of 0 to 30, e and f each independently represent an integer of 1 to 200, the sum of c, d, e and f is 2 or more, and the order of the repeating units assigned with c, d, e or f is arbitrary.)

[0024] According to the present disclosure, it is possible to provide a composition capable of reducing the resistance of an electrochemical device having a sulfide solid electrolyte, a mixture for electrochemical devices, a mixture sheet for electrochemical devices, an electrochemical device, and a method for producing a mixture sheet for electrochemical devices.

[0025] The present disclosure will be specifically described below.

[0026] <Composition> The present disclosure relates to a composition including a sulfide solid electrolyte, a fluoropolyether, and a fibrillar resin.

[0027] The composition of the present disclosure has the above-described configuration, and therefore can reduce the resistance of an electrochemical device having a sulfide solid electrolyte.

[0028] The sulfide solid electrolyte is not particularly limited, and may be Li ２ S-P ２ S ５ , Li ２ S-P ２ S ３ , Li ２ S-P ２ S ３ -P ２ S ５ , Li ２ S-SiS ２ , LiI-Li ２ S-SiS ２ , LiI-Li ２ S-P ２ S ５ , LiI-Li２ S-P ２ O ５ , LiI-Li ３ P.O. ４ -P ２ S ５ , LiI-Li ２ S-SiS ２ -P ２ S ５ , Li ２ S-SiS ２ -Li ４ SiO ４ , Li ２ S-SiS ２ -Li ３ P.O. ４ , Li ３ P.S. ４ -Li ４ GeS ４ , Li ３．４ P ０．６ Si ０．４ S ４ , Li ３．２５ P ０．２５ Ge ０．７６ S ４ , Li ４－ｘ Ge １－ｘ P ｘ S ４ (X=0.6~0.8), Li ４＋ｙ Ge １－ｙ Ga ｙ S ４ (y=0.2-0.3), LiPSCl, LiCl, Li ７－ｘ－２ｙ P.S. ６－ｘ－ｙ Cl ｘ (0.8≦x≦1.7, 0<y≦-0.25x+0.5), Li １０ SnP ２ S １２ , LiI-LiBr-Li ２ S-P ２ S ５ Any one selected from the following, or a mixture of two or more thereof, can be used. Among them, LiI-LiBr-Li ２ S-P ２ S ５ is particularly preferred.

[0029] The sulfide solid electrolyte preferably contains lithium. The sulfide solid electrolyte containing lithium is used in a solid-state battery that uses lithium ions as a carrier, and is particularly preferred in terms of electrochemical devices having a high energy density.

[0030] In the composition of the present disclosure, the content of the sulfide solid electrolyte is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, and is preferably 99.9% by mass or less.

[0031] As the fluoropolyether, at least one of the compounds represented by the following formulas (1) to (4) can be suitably used. １ ~Rb ４ The compound of the following formulas (1) to (3) exhibits good lubricity and reduces grain boundary resistance. １ ~Ra ３ The portion R provides ionic conductivity, thereby further reducing the grain boundary resistance. １ -O-Ra １ -Rb １ -O-Ra １ -R １ (2) R ２ -Rb ２ -O-Ra ２ -Rb ２ -R ２ (3) R ３ -Rb ３ -O-Ra ３ -R ３ (4) R ４ -Rb ４ -R ４ (In the formula, Ra １ ~Ra ３ are each independently a group containing a fluorine-free alkylene unit and / or a fluorine-free oxyalkylene unit, １ ~Ra ３ Each oxyalkylene unit is independently —CH ２ CH ２ O- or -CH ２ CH(J)O—, each J is independently an alkyl group or an aryl group, and Rb１ ~Rb ４ are each independently a fluoropolyether group represented by the following formula (5), １ ~R ３ are each independently a hydrogen atom, a hydroxyl group, a fluorine atom, an alkyl group having 1 to 3 carbon atoms, an aryl group, a carboxylic acid group, or a fluoroalkyl group having 1 to 3 carbon atoms, ４ are each independently a fluorine atom, a hydrogen atom, a hydroxyl group, an aldehyde group, a carboxylic acid group, an alkyl ester group having 1 to 10 carbon atoms, an amide group which may have a substituent, or an amino group which may have a substituent. １ -Rf-O-Rf ２ - (wherein, Rf １ and Rf ２ are each independently an alkylene group having 1 to 16 carbon atoms which may be substituted with a fluorine atom, and Rf is a divalent fluoropolyether group.

[0032] Ra １ ~Ra ３ The alkylene unit may be linear or branched, but is preferably linear, and preferably has 1 to 3 carbon atoms.

[0033] Ra １ ~Ra ３ The oxyalkylene unit is -CH ２ In the case of CH(J)O-, the alkyl group for J may be linear or branched, but is preferably linear. The alkyl group for J preferably has 1 to 3 carbon atoms. Examples of the aryl group for J include a phenyl group, a 4-nitrophenyl group, a 4-acetylaminophenyl group, and a 4-methanesulfonylphenyl group.

[0034] Ra １ ~Ra ３ In the formula (I), the total number of fluorine-free alkylene units and fluorine-free oxyalkylene units is preferably 4 to 50.

[0035] Ra １ ~Ra ３Each of the groups preferably independently contains at least an oxyalkylene unit, and is more preferably a polyoxyalkylene group represented by the following formula (Ra-I): (Ra-I): —(CH ２ CH ２ O)r-(CH ２ CH (CH ３ )O)s-(CH ２ CH (CH ２ CH ３ )O)t-(CH ２ CH(Ph)O)u- (wherein r, s, t, and u each independently represent an integer of 0 or 1 or greater, and r+s+t+u is 4 to 50.)

[0036] In the above formula (Ra-I), r is preferably 1 or more, more preferably 2 or more, and preferably 30 or less, more preferably 20 or less. s, t, and u are preferably 10 or less, more preferably 5 or less, and even more preferably 0. r+s+t+u is preferably 1 or more, more preferably 2 or more, and preferably 20 or less, more preferably 10 or less.

[0037] Ra １ ~Ra ３ The number average molecular weight of the polymer is preferably 40 or more, more preferably 100 or more, and is preferably 4000 or less, more preferably 1000 or less. １ ~Ra ３ The number average molecular weight of １ This is a value measured by H-NMR.

[0038] Rb １ ~Rb ４ In the formula (5), Rf １ and Rf ２ The alkylene group of Rf may be linear or branched, but is preferably linear. １ and Rf ２ The alkylene group of Rf is preferably a fluorine-substituted alkylene group substituted with a fluorine atom. １ and Rf ２ The alkylene group preferably has 1 to 3 carbon atoms.

[0039] Rb １ ~Rb ４ In the above formula (5), Rf may have a ring structure.

[0040] Rb １ ~Rb ４ In the formula (5), Rf is preferably a fluoropolyether group represented by the following formula (Rf-I): Formula (Rf-I): -(OC ６ F １２ ) a-(OC ５ F １０ ) b-(OC ４ F ８ ) c-(OC ３ Rc ６ ) d-(OC ２ F ４ ) e-(OCF ２ )f- (In the formula, each Rc is independently a hydrogen atom, a fluorine atom, or a chlorine atom; each a, b, c, d, e, and f is independently an integer of 0 to 200; the sum of a, b, c, d, e, and f is 1 or more; the order of the repeating units assigned with a, b, c, d, e, or f is arbitrary; and when all Rc's are hydrogen atoms or chlorine atoms, at least one of a, b, c, e, and f is 1 or more.)

[0041] Rc is preferably a hydrogen atom or a fluorine atom, more preferably a fluorine atom, That is, Rf in formula (5) is preferably a perfluoropolyether group.

[0042] Preferably, a, b, c, d, e and f are each independently an integer of 0 to 100.

[0043] The sum of a, b, c, d, e, and f is preferably 5 or more, more preferably 10 or more, and may be 15 or more or 20 or more. The sum of a, b, c, d, e, and f is preferably 100 or less, more preferably 60 or less, and may be 50 or less or 30 or less.

[0044] Each repeating unit to which a, b, c, d, e, or f is assigned may be linear or branched. ６ F １２)- is, for example, -(OCF ２ CF ２ CF ２ CF ２ CF ２ CF ２ )-,-(OCF(CF ３ )CF ２ CF ２ CF ２ CF ２ ) -, -(OCF ２ CF (CF ３ )CF ２ CF ２ CF ２ ) -, -(OCF ２ CF ２ CF (CF ３ )CF ２ CF ２ ) -, -(OCF ２ CF ２ CF ２ CF (CF ３ )CF ２ ) -, -(OCF ２ CF ２ CF ２ CF ２ CF (CF ３ ))-. ５ F １０ )- is, for example, -(OCF ２ CF ２ CF ２ CF ２ CF ２ )-,-(OCF(CF ３ )CF ２ CF ２ CF ２ ) -, -(OCF ２ CF (CF ３ )CF ２ CF ２ ) -, -(OCF ２ CF ２ CF (CF ３ )CF ２ ) -, -(OCF ２ CF ２ CF ２ CF (CF ３ ))-. ４ F ８ )- is, for example, -(OCF２ CF ２ CF ２ CF ２ )-,-(OCF(CF ３ )CF ２ CF ２ ) -, -(OCF ２ CF (CF ３ )CF ２ ) -, -(OCF ２ CF ２ CF (CF ３ )) -, -(OC(CF ３ ) 2CF ２ ) -, -(OCF ２ C (CF ３ )2)-,-(OCF(CF ３ )CF(CF ３ ))-,-(OCF(C2F5)CF ２ ) -, -(OCF ２ CF(C2F5))-. ３ F ６ )-(that is, in the above formula (Rf-I), when all Rc's are fluorine atoms), can be represented by, for example, -(OCF ２ CF ２ CF ２ )-,-(OCF(CF ３ )CF ２ ) -, -(OCF ２ CF (CF ３ ))-. ２ F ４ )- is, for example, -(OCF ２ CF ２ )-,-(OCF(CF ３ ))-.

[0045] Rf may be a group represented by any one of the following formulae (Rf-II) to (Rf-IV): Formula (Rf-II): -(OC ３ F ６ ) d-(OC ２ F ４ )e- (wherein d is an integer of 1 to 200, and e is 0 or 1) Formula (Rf-I-II): -(OC ４ F ８ ) c-(OC ３ F ６) d-(OC ２ F ４ ) e-(OCF ２ )f- (wherein c and d each independently represent an integer of 0 to 30, e and f each independently represent an integer of 1 to 200, the sum of c, d, e and f is 2 or more, and the order of the repeating units assigned with c, d, e or f is arbitrary.) Formula (Rf-I-III): -(R ２０ -R ２１ ) g- (wherein, R ２０ is OCF ２ or O.C. ２ F ４ and R ２１ is O.C. ２ F ４ , O.C. ３ F ６ , O.C. ４ F ８ , O.C. ５ F １０ and O.C. ６ F １２ or a combination of two or three groups selected from these groups, and g is an integer of 2 to 100.) Formula (Rf-I-IV): -(OC ６ F １２ ) a-(OC ５ F １０ ) b-(OC ４ F ８ ) c-(OC ３ F ６ ) d-(OC ２ F ４ ) e-(OCF ２ )f- (wherein e is an integer of 1 to 200, a, b, c, d and f each independently are an integer of 0 to 200, and the order of the repeating units to which a, b, c, d, e or f is assigned is arbitrary.) Formula (Rf-IV): -(OC ６ F １２ ) a-(OC ５ F １０ ) b-(OC ４ F ８ ) c-(OC ３ F ６ ) d-(OC ２ F ４ ) e-(OCF ２)f- (wherein f is an integer of 1 to 200, a, b, c, d, and e each independently are an integer of 0 to 200, and the order of the repeating units assigned a, b, c, d, e, or f is arbitrary.)

[0046] In the above formula (Rf-II), d may be preferably 5 to 200, more preferably 10 to 100, and even more preferably 10 to 30. The above formula (Rf-II) is preferably -(OCF ２ CF ２ CF ２ ) d- or -(OCF(CF ３ )CF ２ ) d- is a group represented by the formula:

[0047] In the above formula (Rf-I-II), e and f are each independently an integer of preferably 5 to 200, more preferably 10 to 200. The sum of c, d, e and f is preferably 5 or more, more preferably 10 or more, and may be 15 or more or 20 or more. The above formula (Rf-I-II) is preferably -(OCF ２ CF ２ CF ２ CF ２ )c-(OCF ２ CF ２ CF ２ ) d-(OCF ２ CF ２ ) e-(OCF ２ )f-, or a group represented by -(OC ２ F ４ ) e-(OCF ２ )f-, and more preferably, -(OC ２ F ４ ) e-(OCF ２ )f- is a group represented by the formula:

[0048] In the above formula (Rf-I-III), R ２０ is preferably OC ２ F ４ and R ２１ is preferably OC ２ F ４ , O.C. ３ F ６ and O.C. ４ F８ or a combination of two or three groups independently selected from these groups, more preferably OC ３ F ６ and O.C. ４ F ８ is a group selected from ２ F ４ , O.C. ３ F ６ and O.C. ４ F ８ Examples of the combination of two or three groups independently selected from the group consisting of, but not limited to, -OC ２ F ４ O.C. ３ F ６ -, -OC ２ F ４ O.C. ４ F ８ -, -OC ３ F ６ O.C. ２ F ４ -, -OC ３ F ６ O.C. ３ F ６ -, -OC ３ F ６ O.C. ４ F ８ -, -OC4F8OC ４ F ８ -, -OC ４ F ８ O.C. ３ F ６ -, -OC ４ F ８ O.C. ２ F ４ -, -OC ２ F ４ OC2F4OC ３ F ６ -, -OC ２ F ４ O.C. ２ F ４ O.C. ４ F ８ -, -OC ２ F ４ O.C. ３ F ６ OC2F4-, -OC ２ F ４ O.C.３ F ６ O.C. ３ F ６ -, -OC ２ F ４ O.C. ４ F ８ O.C. ２ F ４ -, -OC ３ F ６ O.C. ２ F ４ O.C. ２ F ４ -, -OC ３ F ６ O.C. ２ F ４ O.C. ３ F ６ -, -OC ３ F ６ OC3F6OC ２ F ４ - and -OC ４ F ８ O.C. ２ F ４ O.C. ２ F ４ In the above formula (Rf-I-III), g is preferably an integer of 3 or more, more preferably an integer of 5 or more. The above g is preferably an integer of 50 or less. In the above formula (Rf-I-III), OC ２ F ４ , O.C. ３ F ６ , O.C. ４ F ８ , O.C. ５ F １０ , and O.C. ６ F １２ may be either a straight chain or a branched chain, and is preferably a straight chain. In this embodiment, the above formula (Rf-I-III) is preferably —(OC ２ F ４ -OC ３ F ６ ) g- or -(OC ２ F ４ -OC ４ F ８ ) g-.

[0049] In the above formula (Rf-I-IV), e is preferably an integer of 1 to 100, more preferably an integer of 5 to 100. The sum of a, b, c, d, e, and f is preferably 5 or more, more preferably 10 or more, for example, 10 to 100.

[0050] In the above formula (Rf-IV), f is preferably an integer of 1 to 100, more preferably an integer of 5 to 100. The sum of a, b, c, d, e, and f is preferably 5 or more, more preferably 10 or more, for example, 10 to 100.

[0051] In Rf, the ratio of e to f (hereinafter referred to as the "e / f ratio") may be 0.5 to 4, preferably 0.6 to 3, more preferably 0.7 to 2, and even more preferably 0.8 to 1.4. By setting the e / f ratio to 4 or less, lubricity and chemical stability are further improved. The smaller the e / f ratio, the more improved the lubricity. On the other hand, by setting the e / f ratio to 0.5 or more, the stability of the compound can be further increased. The larger the e / f ratio, the more improved the stability of the fluoropolyether structure. In this case, the e / f ratio is preferably 0.8 or more.

[0052] Rf is represented by the following formula (Rf-I-VI): -(OCF ２ CF ２ CF ２ )a-(OCF(CF ３ )CF ２ ) b-(OCF ２ CF(CF3))c-(OCF ２ CF ２ )d-(OCF(CF ３ ))e-(OCF ２ )f- (wherein a, b, c, d, e, and f each independently represent an integer of 0 to 200, the sum of a, b, c, d, e, and f is 1 or more, and the order of the repeating units assigned with a, b, c, d, e, or f is arbitrary).

[0053] Rf is represented by the following formula (Rf-I-VII): -(OCF ２ CF ２ )d-(OCF(CF ３ ))e-(OCF ２)f- (wherein d, e, and f each independently represent an integer of 0 to 200, the sum of d, e, and f is 1 or more, and the order of the repeating units to which d, e, or f is added is arbitrary.) When Rf is this group, it is thought that an increase in the number of ether bonds facilitates coordination of salt cations, thereby improving salt solubility.

[0054] In Rf, the ratio of d to f (hereinafter referred to as the "d / f ratio") may be 0.5 to 4, preferably 0.6 to 3, more preferably 0.7 to 2, and even more preferably 0.8 to 1.4. By setting the d / f ratio to 4 or less, lubricity and chemical stability are further improved. The smaller the d / f ratio, the more improved the lubricity. On the other hand, by setting the d / f ratio to 0.5 or more, the stability of the compound can be further increased. The larger the d / f ratio, the more improved the stability of the fluoropolyether structure. In this case, the d / f ratio is preferably 0.8 or more.

[0055] Each Rf is preferably independently a group represented by the above formula (Rf-II) or (Rf-I-II), and more preferably a group represented by the above formula (Rf-I-II).

[0056] The number average molecular weight of Rf is not particularly limited, but is, for example, 500 to 30,000, preferably 1,500 to 30,000, and more preferably 2,000 to 10,000. １９ This is a value measured by F-NMR.

[0057] R １ ~R ３ The alkyl group and fluoroalkyl group of R may be linear or branched, but are preferably linear. １ ~R ３ Examples of the aryl group include a phenyl group, a 4-nitrophenyl group, a 4-acetylaminophenyl group, and a 4-methanesulfonylphenyl group.

[0058] R １ ~R ３are each independently preferably an alkyl group having 1 to 3 carbon atoms or a fluoroalkyl group having 1 to 3 carbon atoms, more preferably a methyl group, an ethyl group, a trifluoromethyl group or a pentafluoroethyl group, and even more preferably a methyl group, a trifluoromethyl group or a pentafluoroethyl group.

[0059] R ４ The alkyl ester group may be linear or branched.

[0060] R ４ Examples of the substituent that the amide group or amino group may have include an alkyl group, an alkoxy group, and a hydroxy group.

[0061] R ４ are each independently preferably a fluorine atom, a hydrogen atom, a hydroxyl group, an aldehyde group, a carboxylic acid group, an alkyl ester group having 1 to 10 carbon atoms, an amide group which may have a substituent, or an amino group which may have a substituent, and more preferably a fluorine atom. ４ is a fluorine atom, R ４ -Rb ４ and Rb ４ -R ４ , that is, R ４ -Rf １ and Rf ２ -R ４ are each independently -CF ３ , -CF ２ CF ３ , and -CF ２ CF ２ CF ３ It may be a group selected from the group consisting of:

[0062] The fluoropolyether is preferably at least one selected from the group consisting of the formula (1) and the formula (4), and particularly preferably the formula (1), because it has good ionic conductivity and the like.

[0063] The fluoropolyether is preferably a liquid at any temperature between 25°C and 80°C, more preferably a liquid at 25°C, because it has good ionic conductivity and the like. Examples of a form "liquid at any temperature between 25°C and 80°C" include a form that is solid at 25°C and liquid at 50°C, and a form that is solid at 50°C and liquid at 80°C. A form that is liquid at low temperatures and solid at high temperatures does not normally exist, and therefore is not included in the form "liquid at any temperature between 25°C and 80°C".

[0064] In the composition of the present disclosure, the content of the fluoropolyether is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, relative to the solid material, and is preferably 25% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. The solid material is a material to which the lubricating function is imparted by the fluoropolyether, and is solid after mixing with the fluoropolyether. Substances that dissolve in the fluoropolyether after mixing (such as lithium salts) are not included in the solid material. In the examples described below, the positive electrode active material, solid electrolyte, conductive additive, and binder (fibrillar resin) correspond to the solid material.

[0065] The fibrillating resin is a resin that easily fibrillates when shear stress is applied, and examples thereof include liquid crystal polymer (LCP), cellulose, acrylic resin, ultra-high molecular weight polyethylene, polytetrafluoroethylene (PTFE), etc. These may be used alone or in combination of two or more. Among these, PTFE is preferred from the viewpoints of chemical stability, thermal stability, and processability.

[0066] The PTFE may be a homopolymer of tetrafluoroethylene (TFE), or may be a modified PTFE containing a polymerized unit based on TFE (TFE unit) and a polymerized unit based on a modified monomer (hereinafter also referred to as "modified monomer unit"). The modified PTFE may contain 99.0 mass% or more of TFE unit and 1.0 mass% or less of modified monomer unit. The modified PTFE may also be composed of only TFE unit and modified monomer unit. The modified PTFE is preferred as the PTFE because it improves binding force, sheet strength and flexibility.

[0067] In order to improve the binding force, sheet strength, and flexibility of the modified PTFE, the content of the modified monomer unit is preferably in the range of 0.00001 to 1.0 mass% relative to the total polymerized units. The lower limit of the content of the modified monomer unit is more preferably 0.0001 mass%, even more preferably 0.001 mass%, even more preferably 0.005 mass%, and particularly preferably 0.010 mass%. The upper limit of the content of the modified monomer unit is preferably 0.90 mass%, more preferably 0.80 mass%, more preferably 0.50 mass%, even more preferably 0.40 mass%, and even more preferably 0.30 mass%. In this specification, the modified monomer unit refers to a part of the molecular structure of PTFE that is derived from the modified monomer.

[0068] The content of each of the above-mentioned polymerized units can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and X-ray fluorescence analysis depending on the type of monomer.

[0069] The above-mentioned modified monomer is not particularly limited as long as it can be copolymerized with TFE, and for example, can be listed perfluoroolefin such as hexafluoropropylene (HFP); hydrogen-containing fluoroolefin such as trifluoroethylene, vinylidene fluoride (VDF); perhaloolefin such as chlorotrifluoroethylene (CTFE); perfluorovinyl ether; perfluoroallyl ether; (perfluoroalkyl) ethylene, ethylene etc. In addition, the modified monomer used can be one kind or multiple kinds.

[0070] The perfluorovinyl ether is not particularly limited, and examples thereof include perfluorovinyl ethers represented by the following general formula (A): CF ２ =CF-ORff (A) (wherein Rff represents a perfluoroorganic group). In this specification, the term "perfluoroorganic group" refers to an organic group in which all hydrogen atoms bonded to carbon atoms are substituted with fluorine atoms. The perfluoroorganic group may have an ether oxygen.

[0071] Examples of the perfluorovinyl ether include perfluoro(alkyl vinyl ether) [PAVE], in which Rff in the general formula (A) is a perfluoroalkyl group having 1 to 10 carbon atoms. The number of carbon atoms in the perfluoroalkyl group is preferably 1 to 5.

[0072] Examples of the perfluoroalkyl group in the PAVE include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, and a perfluorohexyl group.

[0073] The perfluorovinyl ether further includes those in which Rff is a perfluoro(alkoxyalkyl) group having 4 to 9 carbon atoms in the general formula (A), and those in which Rff is a perfluoro(alkoxyalkyl) group having 4 to 9 carbon atoms in the general formula (A)

[0074]

[0075] (wherein m represents 0 or an integer of 1 to 4), and Rff is a group represented by the following formula:

[0076]

[0077] (wherein n represents an integer of 1 to 4).

[0078] The (perfluoroalkyl)ethylene [PFAE] is not particularly limited, and examples thereof include (perfluorobutyl)ethylene [PFBE] and (perfluorohexyl)ethylene.

[0079] Examples of perfluoroallyl ethers include those represented by the general formula (B): CF ２=CF-CF ２ -ORff １ (B) (wherein, Rff １ represents a perfluoroorganic group.

[0080] The above Rff １ is preferably a perfluoroalkyl group having 1 to 10 carbon atoms or a perfluoroalkoxyalkyl group having 1 to 10 carbon atoms. ２ =CF-CF ２ -O-CF ３ , C.F. ２ =CF-CF ２ -O-C ２ F ５ , C.F. ２ =CF-CF ２ -O-C ３ F ７ , and CF ２ =CF-CF ２ -O-C ４ F ９ At least one selected from the group consisting of CF ２ =CF-CF ２ -O-C ２ F ５ , C.F. ２ =CF-CF ２ -O-C ３ F ７ , and CF ２ =CF-CF ２ -O-C ４ F ９ More preferably, at least one selected from the group consisting of CF ２ =CF-CF ２ -O-CF ２ CF ２ CF ３ is more preferred.

[0081] The modified monomer is preferably at least one selected from the group consisting of PAVE, HFP, VDF, and CTFE, and more preferably at least one selected from the group consisting of perfluoro(methyl vinyl ether) [PMVE], HFP, VDF, and CTFE, in terms of improving the stretchability, binding strength, and flexibility of the composite sheet.

[0082] The PTFE may have a core-shell structure. Examples of PTFE having a core-shell structure include modified PTFE particles containing a core of high molecular weight PTFE and a shell of lower molecular weight PTFE or modified PTFE. Examples of such modified PTFE include the PTFE described in JP-A-2005-527652.

[0083] Examples of commonly available PTFE include F-104, F-106, F-107, F-104C, F-121, F-201, F-205, F-208, and F-302 manufactured by Daikin Industries, Ltd.; 60X, 601X, 602X, 605XTX, 613AX, 62X, 62NX, 62XTX, 640XTX, 641XTX, 650XTX, 669X, 669NX, 6CX, 6CNX, CFP6000X, 6J, 6CJ, 62J, 640J, and 641J manufactured by Chemours; and T F2029, TF2025Z, TF2053Z, TF2073Z, TF2001Z, TF2071USZ, TF2072Z, etc.; CD145, CD123, CD126E, CD097, CD084E, CD086EL, CD086EH, CD090E, CD122E, CD141E, CD127E, etc. manufactured by AGC; and DF681F, DF680F, DF330F, DF291F, DF230F, DF210F, DF132F, DF130F, DF120F manufactured by Solvay.

[0084] The PTFE preferably has an endothermic peak temperature of 320°C or higher, more preferably 325°C or higher, even more preferably 330°C or higher, even more preferably 335°C or higher, even more preferably 340°C or higher, even more preferably 342°C or higher, and particularly preferably 344°C or higher, in order to form a composite sheet with even greater strength. The endothermic peak temperature is also preferably 350°C or lower. The endothermic peak temperature is the temperature corresponding to the minimum point in the heat of fusion curve obtained by performing differential scanning calorimetry (DSC) at a heating rate of 10°C / min on PTFE that has no history of being heated to a temperature of 300°C or higher. When there are two or more minimum points in one melting peak, each of them is taken as the endothermic peak temperature.

[0085] The PTFE preferably exhibits one or more endothermic peaks in the range of 333 to 347°C in the heat of fusion curve when heated at a rate of 10°C / min using a differential scanning calorimeter (DSC), and the heat of fusion at 290 to 350°C calculated from the heat of fusion curve is 62mJ / mg or more.

[0086] In the composition of the present disclosure, the content of the fibrillar resin is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, even more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more, relative to the solid materials other than the fibrillar resin and other binders described below, and is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and even more preferably 10% by mass or less.

[0087] In the composition of the present disclosure, the content of the polyalkylene oxide represented by the following formula (6) is preferably less than 20% by mass. This ensures good ionic conductivity. If the content is 20% by mass or more, the viscosity of the composition increases, the ionic conductivity decreases, and the electrochemical stability tends to decrease. (6) R １Ｂ -(OCHR １Ａ (CH ２ ) jCHR ２Ａ ) n-OR ２Ｂ (In the formula, R １Ａ and R２Ａ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, j is an integer of 0 or 1 or 2, and R １Ｂ and R ２Ｂ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and n is an integer of 5 to 1000.

[0088] In the composition of the present disclosure, the content of the polyalkylene oxide represented by the above formula (6) is more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 1% by mass or less. The lower limit is not particularly limited, and may be 0% by mass.

[0089] The composition of the present disclosure may contain a lithium salt, which improves the conductivity of lithium ions.

[0090] Any lithium salt can be used, and specific examples include the following: LiPF ６ , LiBF ４ , LiClO ４ , LiAlF ４ , LiSbF ６ , LiTaF ６ , LiWF ７ , LiAsF ６ , LiAlCl ４ , LiI, LiBr, LiCl, LiB １０ Cl １０ , Li ２ SiF ６ , Li ２ PFO ３ , LiPO ２ F ２ Inorganic lithium salts such as LiWOF ５ Lithium tungstates such as HCO ２ Li, C.H. ３ CO ２ Li, C.H. ２ FCO ２ Li, CHF ２ CO ２ Li, CF ３ CO ２ Li, CF ３ CH ２ CO ２ Li, CF３ CF ２ CO ２ Li, CF ３ CF ２ CF ２ CO ２ Li, CF ３ CF ２ CF ２ CF ２ CO ２ Lithium carboxylate salts such as Li; FSO ３ Li, C.H. ３ SO ３ Li, C.H. ２ FSO ３ Li, CHF ２ SO ３ Li, CF ３ SO ３ Li, CF ３ CF ２ SO ３ Li, CF ３ CF ２ CF ２ SO ３ Li, CF ３ CF ２ CF ２ CF ２ SO ３ Li, lithium methyl sulfate, lithium ethyl sulfate (C ２ H ５ OSO ３ Lithium salts having an S═O group, such as lithium bis(trifluoromethanesulfonimide) (LiTFSI), lithium bis(monofluorosulfonimide) (LiFSI), and LiN(FCO). ２ , LiN(FCO)(FSO ２ ), LiN(FSO ２ ) ２ , LiN(FSO ２ ) (CF ３ SO ２ ), LiN(CF ３ SO ２ ) ２ , LiN(C ２ F ５ SO ２ ) ２, lithium bisperfluoroethanesulfonylimide, lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropanedisulfonylimide, lithium cyclic 1,2-ethanedisulfonylimide, lithium cyclic 1,3-propanedisulfonylimide, lithium cyclic 1,4-perfluorobutanedisulfonylimide, LiN(CF ３ SO ２ ) (FSO ２ ), LiN(CF ３ SO ２ ) (C ３ F ７ SO ２ ), LiN(CF ３ SO ２ ) (C ４ F ９ SO ２ ), LiN (POF ２ ) ２ Lithium imide salts such as LiC(FSO ２ ) ３ , LiC(CF ３ SO ２ ) ３ , LiC(C ２ F ５ SO ２ ) ３ Lithium methide salts such as: ａ (C ｎ F ２ｎ＋１ ) ６－ａ (wherein a is an integer of 0 to 5, and n is an integer of 1 to 6) ３ (C ２ F ５ ) ３ , LiPF ３ (CF ３ ) ３ , LiPF ３ (iso-C ３ F ７ ) ３ , LiPF ５ (iso-C ３ F ７ ), LiPF ４ (CF ３ ) ２ , LiPF ４ (C ２ F５ ) ２ ), LiPF ４ (CF ３ SO ２ ) ２ , LiPF ４ (C ２ F ５ SO ２ ) ２ , LiBF ３ CF ３ , LiBF ３ C ２ F ５ , LiBF ３ C ３ F ７ , LiBF ２ (CF ３ ) ２ , LiBF ２ (C ２ F ５ ) ２ , LiBF ２ (CF ３ SO ２ ) ２ , LiBF ２ (C ２ F ５ SO ２ ) ２ Fluorine-containing organic lithium salts such as LiSCN and LiB(CN) ４ , LiB(C ６ H ５ ) ４ , Li ２ (C ２ O ４ ), LiP(C ２ O ４ ) ３ , Li ２ B １２ F ｂ H １２－ｂ (b is an integer of 0 to 3), etc.

[0091] Among them, LiTFSI, LiFSI, LiPF ６ , LiBF ４ , LiSbF ６ , LiTaF ６ , LiPO ２ F ２ , FSO ３ Li, CF ３ SO ３Li, LiN (FSO ２ ) ２ , LiN(FSO ２ ) (CF ３ SO ２ ), LiN(CF ３ SO ２ ) ２ , LiN(C ２ F ５ SO ２ ) ２ , lithium cyclic 1,2-perfluoroethane disulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiC(FSO ２ ) ３ , LiC(CF ３ SO ２ ) ３ , LiC(C ２ F ５ SO ２ ) ３ , LiBF ３ CF ３ , LiBF ３ C ２ F ５ , LiPF ３ (CF ３ ) ３ , LiPF ３ (C ２ F ５ ) ３ and the like are preferred, and LiTFSI, LiFSI, LiPF ６ is particularly preferred.

[0092] These lithium salts may be used alone or in combination of two or more. A preferred example of a combination of two or more is LiPF ６ and LiBF ４ In combination with LiPF ６ and LiPO ２ F ２ , C ２ H ５ OSO ３ Li or FSO ３ When used in combination with Li, it has the effect of improving high-temperature storage characteristics, load characteristics, and cycle characteristics.

[0093] Another example is the combined use of an inorganic lithium salt and an organic lithium salt, which has the effect of suppressing deterioration due to high-temperature storage. ３ SO ３ Li, LiN (FSO ２ ) ２ , LiN(FSO ２ ) (CF ３ SO ２ ), LiN(CF ３ SO ２ ) ２ , LiN(C ２ F ５ SO ２ ) ２ , lithium cyclic 1,2-perfluoroethane disulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiC(FSO ２ ) ３ , LiC(CF ３ SO ２ ) ３ , LiC(C ２ F ５ SO ２ ) ３ , LiBF ３ CF ３ , LiBF ３ C ２ F ５ , LiPF ３ (CF ３ ) ３ , LiPF ３ (C ２ F ５ ) ３ etc. are preferred.

[0094] In the composition of the present disclosure, the content of the lithium salt relative to the fluoropolyether is preferably 0.1% by mass or more, more preferably 1% by mass or more, and is preferably 30% by mass or less, more preferably 20% by mass or less.

[0095] <Mixture for Electrochemical Device> The composition of the present disclosure is useful as a mixture for electrochemical devices because it can reduce the resistance of electrochemical devices. The present disclosure also relates to a mixture for electrochemical devices containing the composition of the present disclosure.

[0096] In the mixture for electrochemical devices according to the present disclosure, the content of the composition according to the present disclosure is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and is preferably 99.9% by mass or less, more preferably 99.5% by mass or less, even more preferably 99% by mass or less.

[0097] The electrochemical device mixture of the present disclosure may contain a conductive aid. Examples of the conductive aid include, but are not limited to, metal materials such as copper, nickel, and gold; graphite such as natural graphite and artificial graphite; carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; and carbon materials such as needle coke, carbon nanotubes, fullerenes, and amorphous carbon such as vapor-grown carbon fiber (VGCF). Of these, carbon materials are preferred, amorphous carbon is more preferred, and VGCF is even more preferred. These may be used alone, or two or more may be used in any combination and ratio.

[0098] In the mixture for electrochemical devices according to the present disclosure, the content of the conductive additive is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. The lower limit is not particularly limited, and may be 0% by mass.

[0099] In the mixture for electrochemical devices of the present disclosure, the fibrillar resin acts as a binder, but may further contain other binders. The other binders are not particularly limited, and examples thereof include resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, chitosan, alginic acid, polyacrylic acid, polyimide, cellulose, and nitrocellulose; rubber-like polymers such as SBR (styrene-butadiene rubber), isoprene rubber, butadiene rubber, fluororubber, NBR (acrylonitrile-butadiene rubber), and ethylene-propylene rubber; styrene-butadiene-styrene block copolymers or hydrogenated products thereof; EPDM (ethylene-propylene copolymer); Examples of suitable polymers include thermoplastic elastomeric polymers such as styrene-ethylene-butadiene terpolymers, styrene-isoprene-styrene block copolymers, and hydrogenated products thereof; soft resinous polymers such as syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene-vinyl acetate copolymers, and propylene-α-olefin copolymers; fluorine-containing polymers such as polyvinylidene fluoride, vinylidene fluoride copolymers, and tetrafluoroethylene-ethylene copolymers; and polymer compositions having ionic conductivity for alkali metal ions (particularly lithium ions). These may be used alone or in any combination and ratio of two or more.

[0100] In the mixture for electrochemical devices of the present disclosure, the content of the other binder is usually 0 to 10 mass % based on the solid materials other than the fibrillar resin and the other binder.

[0101] The mixture for electrochemical devices of the present disclosure can be used as a solid electrolyte mixture. In addition, by blending an electrode active material, it can also be used as an electrode mixture.

[0102] The electrode active material may be a positive electrode active material or a negative electrode active material.

[0103] The positive electrode active material is not particularly limited as long as it can electrochemically absorb and release alkali metal ions, but for example, a material containing an alkali metal and at least one transition metal is preferred. Specific examples include alkali metal-containing transition metal composite oxides and alkali metal-containing transition metal phosphate compounds. Of these, alkali metal-containing transition metal composite oxides that generate high voltage are particularly preferred as the positive electrode active material. Examples of the alkali metal ions include lithium ions, sodium ions, and potassium ions, with lithium ions being preferred.

[0104] Examples of the alkali metal-containing transition metal composite oxide include those represented by the formula: M ａ Mn ２－ｂ M １ ｂ O ４ (Wherein, M is at least one metal selected from the group consisting of Li, Na, and K; 0.9≦a; 0≦b≦1.5; M １ and Mn is at least one metal selected from the group consisting of Fe, Co, Ni, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge), a lithium-manganese spinel composite oxide represented by the formula: MNi １－ｃ M ２ ｃ O ２ (Wherein, M is at least one metal selected from the group consisting of Li, Na, and K; 0≦c≦0.5; M ２ is at least one metal selected from the group consisting of Fe, Co, Mn, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge), or a lithium-nickel composite oxide represented by the formula: MCo １－ｄ M ３ ｄ O ２ (Wherein, M is at least one metal selected from the group consisting of Li, Na, and K; 0≦d≦0.5; M ３and M is at least one metal selected from the group consisting of Fe, Ni, Mn, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge. In the above, M is preferably one metal selected from the group consisting of Li, Na, and K, more preferably Li or Na, and even more preferably Li.

[0105] Among these, MCoO is preferred because it can provide a secondary battery with high energy density and high output. ２ , M MnO ２ , MNiO ２ , M.M. ２ O ４ , MNi ０．８ Co ０．１５ Al ０．０５ O ２ , or MNi １／３ Co １／３ Mn １／３ O ２ and the like are preferred, and a compound represented by the following general formula is preferred: MNi ｈ Co ｉ Mn ｊ M ５ ｋ O ２ (wherein M is at least one metal selected from the group consisting of Li, Na, and K, and M ５ represents at least one selected from the group consisting of Fe, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge, and (h+i+j+k)=1.0, 0≦h≦1.0, 0≦i≦1.0, 0≦j≦1.5, 0≦k≦0.2.

[0106] Examples of the alkali metal-containing transition metal phosphate compound include those represented by the following general formula: ｅ M ４ ｆ (P.O. ４ ) ｇ (wherein M is at least one metal selected from the group consisting of Li, Na, and K, and M ４represents at least one selected from the group consisting of V, Ti, Cr, Mn, Fe, Co, Ni, and Cu, and 0.5≦e≦3, 1≦f≦2, and 1≦g≦3. In the above, M is preferably one metal selected from the group consisting of Li, Na, and K, more preferably Li or Na, and even more preferably Li.

[0107] The transition metal in the alkali metal-containing transition metal phosphate compound is preferably V, Ti, Cr, Mn, Fe, Co, Ni, Cu, or the like, and specific examples thereof include LiFePO ４ , Li ３ Fe ２ (P.O. ４ ) ３ , LiFeP ２ O ７ Iron phosphates such as LiCoPO ４ and lithium transition metal phosphate compounds in which a part of the transition metal atoms constituting the main component of these compounds is substituted with other elements such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb, Si, etc. The lithium-containing transition metal phosphate compounds preferably have an olivine structure.

[0108] Other examples of the positive electrode active material include lithium-nickel-based composite oxides. The lithium-nickel-based composite oxides are represented by the following general formula: Li ｙ Ni １－ｘ M ｘ O ２ (wherein x is 0.01≦x≦0.7, y is 0.9≦y≦2.0, and M is a metal atom (excluding Li and Ni)) is preferred.

[0109] Other positive electrode active materials include MFePO ４ , MNi ０．８ Co ０．２ O ２ , M １．２ Fe ０．４ Mn ０．４ O ２ , MNi ０．５ Mn １．５ O ２ , M.V.３ O ６ , M ２ MnO ３ In particular, M ２ MnO ３ , MNi ０．５ Mn １．５ O ２ These positive electrode active materials are preferred in that their crystalline structure does not collapse even when the secondary battery is operated at a voltage exceeding 4.4 V or a voltage of 4.6 V or higher. Therefore, electrochemical devices such as secondary batteries using positive electrode materials containing the above-mentioned positive electrode active materials are preferred because they are less likely to reduce their remaining capacity and change their resistance increase rate even when stored at high temperatures, and their battery performance does not deteriorate even when operated at high voltages.

[0110] Other positive electrode active materials include M ２ MnO ３ and M.M. ６ O ２ (wherein M is at least one metal selected from the group consisting of Li, Na, and K, and M ６ Examples of the material include solid solution materials with transition metals such as Co, Ni, Mn, and Fe.

[0111] The solid solution material may be, for example, a material represented by the general formula M ｘ [Mn （１－ｙ） M ７ ｙ ]O ｚ In the formula, M is at least one metal selected from the group consisting of Li, Na, and K, and M ７ is composed of at least one metal element other than M and Mn, and contains, for example, one or more elements selected from the group consisting of Co, Ni, Fe, Ti, Mo, W, Cr, Zr and Sn. The values ​​of x, y and z in the formula are in the ranges of 1<x<2, 0≦y<1 and 1.5<z<3. Among them, Li １．２ Mn ０．５ Co ０．１４ Ni ０．１４ O ２ Li like ２ MnO ３ Based on LiNiO ２ and LiCoO ２A manganese-containing solid solution material containing manganese is preferred in that it can provide an alkali metal ion secondary battery having a high energy density.

[0112] Furthermore, it is preferable to include lithium phosphate in the positive electrode active material, since this improves continuous charging characteristics. Although there is no limitation on the use of lithium phosphate, it is preferable to use a mixture of the positive electrode active material and lithium phosphate. The amount of lithium phosphate used, based on the total amount of the positive electrode active material and lithium phosphate, is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more, and is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 5% by mass or less.

[0113] Alternatively, a substance having a different composition may be attached to the surface of the positive electrode active material, such as an oxide, such as aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, or bismuth oxide; a sulfate, such as lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, or aluminum sulfate; a carbonate, such as lithium carbonate, calcium carbonate, or magnesium carbonate; or carbon.

[0114] The positive electrode active material may be used alone or in any combination or ratio of two or more different types of materials. ２ and LiNi ０．３３ Co ０．３３ Mn ０．３３ O ２ combination with ternary systems such as LiCoO ２ and LiMn ２ O ４ Or a combination of this with a material in which a part of Mn is replaced with another transition metal, or LiFePO ４ and LiCoO ２ Alternatively, a combination of Co with other transition metals or the like may be used.

[0115] The content of the positive electrode active material is preferably 50 to 90% by mass of the positive electrode mixture in terms of high battery capacity. The content in the positive electrode active material layer is preferably 60% by mass or more, more preferably 70% by mass or more, and particularly preferably 75% by mass or more. The upper limit is preferably 88% by mass or less, more preferably 86% by mass or less. If the content of the positive electrode active material in the positive electrode active material layer is low, the electrical capacity may be insufficient. Conversely, if the content is too high, the ionic conductivity, electronic conductivity, and electrode strength may be insufficient.

[0116] The negative electrode active material is not particularly limited, and examples thereof include carbonaceous materials such as lithium metal, artificial graphite, graphite carbon fiber, resin-baked carbon, pyrolytic vapor-grown carbon, coke, mesocarbon microbeads (MCMB), furfuryl alcohol resin-baked carbon, polyacene, pitch-based carbon fiber, vapor-grown carbon fiber, natural graphite, and non-graphitizable carbon; silicon-containing compounds such as silicon and silicon alloys; Li ４ Ti ５ O １２ Among these, those containing at least a carbonaceous material and silicon-containing compounds are particularly suitable.

[0117] The negative electrode active material used in the present disclosure preferably contains silicon as a constituent element, which allows the production of a high-capacity battery.

[0118] The silicon-containing material includes silicon particles, particles having a structure in which silicon particles are dispersed in a silicon-based compound, and silicon-based particles having the general formula SiO ｘ (0.5≦x≦1.6), or a mixture thereof. By using these, a negative electrode mixture for a lithium ion secondary battery having higher initial charge / discharge efficiency, high capacity, and excellent cycle characteristics can be obtained.

[0119] Silicon oxide in the present disclosure is a general term for amorphous silicon oxide, and silicon oxide before disproportionation has the general formula SiO ｘ(0.5≦x≦1.6). Preferably, x satisfies 0.8≦x<1.6, and more preferably 0.8≦x<1.3. This silicon oxide can be obtained, for example, by heating a mixture of silicon dioxide and metallic silicon to produce silicon monoxide gas, which is then cooled and precipitated.

[0120] The content of the negative electrode active material is preferably 50 to 90% by mass of the negative electrode mixture in terms of high battery capacity. The content in the negative electrode active material layer is preferably 60% by mass or more, more preferably 70% by mass or more, and particularly preferably 75% by mass or more. The upper limit is preferably 88% by mass or less, more preferably 86% by mass or less. If the content of the negative electrode active material in the negative electrode active material layer is low, the electrical capacity may be insufficient. Conversely, if the content is too high, the ionic conductivity, electronic conductivity, and electrode strength may be insufficient.

[0121] <Material Mixture Sheet for Electrochemical Device> The material mix for electrochemical devices of the present disclosure is preferably in the form of a sheet. The present disclosure also relates to a material mix sheet for electrochemical devices including the material mix for electrochemical devices of the present disclosure.

[0122] The thickness of the composite sheet for electrochemical devices according to the present disclosure is preferably 300 μm or less, more preferably 250 μm or less, even more preferably 200 μm or less, even more preferably 180 μm or less, and particularly preferably 150 μm or less, and is preferably 10 μm or more, more preferably 15 μm or more, and even more preferably 20 μm or more.

[0123] The mixture sheet for electrochemical devices according to the present disclosure can be used as a solid electrolyte mixture sheet or an electrode mixture sheet.

[0124] <Method for manufacturing a mixture sheet for electrochemical device> The mixture sheet for electrochemical device of the present disclosure can be obtained by a manufacturing method including, for example, step (1) of mixing a fluoropolyether, a fibrillar resin, and a sulfide solid electrolyte, and step (2) of rolling the composition obtained in step (1) into a sheet. The present disclosure also relates to the manufacturing method.

[0125] The fluoropolyether, fibrillar resin, and sulfide solid electrolyte in the above step (1) are the same as those described in the composition of the present disclosure.

[0126] In the above step (1), the mixing conditions are preferably 3000 rpm or less. The speed is preferably 10 rpm or more, more preferably 15 rpm or more, and even more preferably 20 rpm or more, and is preferably 2000 rpm or less, more preferably 1500 rpm or less, and even more preferably 1000 rpm or less. If the speed is below the above range, mixing takes a long time, which affects productivity. If the speed is above the above range, fibrillation may proceed excessively, resulting in a mixture sheet with poor strength and flexibility.

[0127] In the above step (1), the materials may be mixed and then shaped into a bulk form. Specific methods for shaping into a bulk form include extrusion molding, press molding, etc. The term "bulk form" does not particularly specify a shape, and may refer to a state in which the material is in the form of a single mass, including rods, sheets, spheres, cubes, etc.

[0128] Specific examples of the rolling method in the step (2) include rolling using a roll press, a plate press, a calender roll, or the like.

[0129] Furthermore, after the above step (2), a step (3) may be carried out in which a larger load is applied to the obtained rolled sheet to roll it into an even thinner sheet, or step (3) may be carried out repeatedly. In this way, by rolling the rolled sheet little by little in stages rather than thinning it all at once, flexibility is improved. The number of times step (3) is carried out is preferably from 2 to 10 times, and more preferably from 3 to 9 times. Specific rolling methods include, for example, a method in which two or more rolls are rotated and the rolled sheet is passed between them to process it into a thinner sheet.

[0130] It is also preferable to include a step (4) after the step (2) or the step (3) in which the rolled sheet is crushed, re-formed into a bulk form, and rolled into a sheet. It is also preferable to repeat the step (4). The number of times of the step (4) is preferably from 1 to 12 times, more preferably from 2 to 11 times.

[0131] In the above step (4), specific methods for roughly crushing the rolled sheet and forming it into a bulk shape include folding the sheet, forming it into a rod or thin film sheet, chipping, etc. In the present disclosure, "rough crushing" means changing the shape of the rolled sheet obtained in step (2) or (3) into a different shape so that it can be rolled into a sheet in the next step, and also includes cases where the rolled sheet is simply folded.

[0132] Furthermore, step (4) may be followed by step (3) or may be repeated. Furthermore, uniaxial or biaxial stretching may be performed in steps (2), (3), and (4).

[0133] In the above steps (2), (3), and (4), the rolling ratio is preferably 10% or more, more preferably 20% or more, and preferably 80% or less, more preferably 65% ​​or less, and even more preferably 50% or less. If the rolling ratio is below the above range, the number of rolling operations increases, which takes time and affects productivity. If the rolling ratio is above the above range, fibrillation may proceed excessively, resulting in a mixture sheet with poor strength and flexibility. The rolling ratio here refers to the reduction rate of the thickness of the sample after processing relative to the thickness before rolling. The sample before rolling may be a bulk raw material composition or a sheet-like raw material composition. The thickness of the sample refers to the thickness in the direction in which a load is applied during rolling.

[0134] <Electrochemical Device> The present disclosure also relates to an electrochemical device using the mixture sheet for an electrochemical device of the present disclosure.

[0135] The electrochemical device of the present disclosure may use the mixture sheet for electrochemical devices of the present disclosure as a solid electrolyte mixture sheet, may use the mixture sheet for electrochemical devices of the present disclosure as an electrode mixture sheet, or may use the mixture sheet as a solid electrolyte mixture sheet and an electrode mixture sheet.

[0136] The electrochemical device of the present disclosure preferably comprises a positive electrode, a negative electrode, etc., and more specifically, is preferably a secondary battery comprising these, and particularly preferably a lithium ion secondary battery.

[0137] The positive electrode is preferably composed of a current collector and an electrode mixture sheet containing the positive electrode active material. Examples of materials for the positive electrode current collector include metals such as aluminum, titanium, tantalum, stainless steel, and nickel, or alloys thereof; and carbon materials such as carbon cloth and carbon paper. Among these, metal materials, particularly aluminum or its alloys, are preferred.

[0138] Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, expanded metal, punched metal, and foam metal in the case of a metal material, and carbon plate, carbon thin film, and carbon cylinder in the case of a carbon material. Of these, metal foil is preferred. The metal foil may be appropriately formed into a mesh shape. The thickness of the metal foil is optional, but is usually 1 μm or more, preferably 3 μm or more, and more preferably 5 μm or more, and is usually 1 mm or less, preferably 100 μm or less, and more preferably 50 μm or less. If the metal foil is thinner than this range, the strength required as a current collector may be insufficient. Conversely, if the metal foil is thicker than this range, handling may be impaired.

[0139] In addition, it is also preferable that the surface of the current collector is coated with a conductive additive, from the viewpoint of reducing the electrical contact resistance between the current collector and the positive electrode active material layer. Examples of the conductive additive include carbon and precious metals such as gold, platinum, and silver.

[0140] The positive electrode may be manufactured by a conventional method, for example, by laminating an electrode mixture sheet and a current collector with an adhesive therebetween, followed by vacuum drying.

[0141] The density of the positive electrode mixture sheet is preferably 2.50 g / cm３ More preferably, 3.00 g / cm ３ More preferably, 3.20 g / cm ３ or more, and preferably 3.80 g / cm ３ or less, more preferably 3.75 g / cm ３ More preferably, 3.70 g / cm or less ３ The range is as follows. If the electrolyte content exceeds this range, the ratio of electrolyte to active material will be low, hindering ion conduction to the active material, which may result in a decrease in charge / discharge characteristics at high current densities and in failure to obtain high output. If the electrolyte content falls below this range, the active material may be insufficient, resulting in poor battery capacity.

[0142] The thickness of the positive electrode is not particularly limited, but from the viewpoint of high capacity and high output, the thickness of the mixture layer minus the thickness of the metal foil of the current collector is preferably 10 μm or more, more preferably 20 μm or more, as a lower limit, and is also preferably 500 μm or less, more preferably 450 μm or less, on one side of the current collector.

[0143] The negative electrode is preferably composed of a current collector and an electrode mixture sheet containing the negative electrode active material. Examples of materials for the negative electrode current collector include metals such as copper, nickel, titanium, tantalum, and stainless steel, or alloys thereof; and carbon materials such as carbon cloth and carbon paper. Among these, metal materials, particularly copper, nickel, and alloys thereof, are preferred.

[0144] Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, expanded metal, punched metal, and foam metal in the case of a metal material, and carbon plate, carbon thin film, and carbon cylinder in the case of a carbon material. Of these, metal foil is preferred. The metal foil may be appropriately formed into a mesh shape. The thickness of the metal foil is optional, but is usually 1 μm or more, preferably 3 μm or more, and more preferably 5 μm or more, and is usually 1 mm or less, preferably 100 μm or less, and more preferably 50 μm or less. If the metal foil is thinner than this range, the strength required as a current collector may be insufficient. Conversely, if the metal foil is thicker than this range, handling may be impaired.

[0145] The negative electrode may be produced by a conventional method, for example, by laminating the electrode mixture sheet and a current collector with an adhesive therebetween, followed by vacuum drying.

[0146] The density of the negative electrode mixture is preferably 1.0 g / cm ３ More preferably, 1.2 g / cm ３ or more, and preferably 2.5 g / cm ３ or less, more preferably 2.2 g / cm ３ Above this range, the ratio of electrolyte to active material is low, hindering ion conduction to the active material, which may result in a decrease in charge / discharge characteristics at high current densities and a failure to obtain high output. Also, below this range, the battery capacity may be poor due to a lack of active material.

[0147] The thickness of the negative electrode is not particularly limited, but from the viewpoint of high capacity and high output, the thickness of the mixture layer minus the thickness of the metal foil of the current collector is preferably 10 μm or more, more preferably 20 μm or more, as a lower limit, and is also preferably 500 μm or less, more preferably 450 μm or less, on one side of the current collector.

[0148] The secondary battery is preferably a solid-state secondary battery. In this specification, the solid-state secondary battery may be a secondary battery containing a solid electrolyte, and may be a semi-solid-state secondary battery containing a solid electrolyte and a liquid component as the electrolyte, or an all-solid-state secondary battery containing only a solid electrolyte as the electrolyte.

[0149] The secondary battery may have any shape, such as a cylindrical shape, a square shape, a laminated shape, a coin shape, a large shape, etc. The shapes and configurations of the positive electrode, the negative electrode, and the mixture sheet can be changed according to the shape of each battery.

[0150] The solid secondary battery is preferably a lithium ion battery, and is also preferably a sulfide-based all-solid secondary battery.

[0151] The solid secondary battery preferably includes a positive electrode, a negative electrode, and a solid electrolyte layer interposed between the positive electrode and the negative electrode.

[0152] The solid secondary battery may include a separator between the positive electrode and the negative electrode. Examples of the separator include a porous membrane such as polyethylene or polypropylene; a nonwoven fabric made of a resin such as polypropylene; and a nonwoven fabric such as a glass fiber nonwoven fabric.

[0153] The solid secondary battery may further include a battery case. The shape of the battery case is not particularly limited as long as it can accommodate the above-mentioned positive electrode, negative electrode, solid electrolyte layer, etc., but specific examples include a cylindrical shape, a square shape, a coin shape, and a laminate shape.

[0154] The solid secondary battery can be produced, for example, by stacking a positive electrode, a solid electrolyte layer sheet, and a negative electrode in this order and pressing them together.

[0155] Although the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims.

[0156] Next, the present disclosure will be described with reference to examples, but the present disclosure is not limited to these examples.

[0157] (Preparation Example) PTFE powder was obtained by changing the fluorine-containing surfactant to ammonium perfluoroether carboxylate with reference to Preparation Example 2 of International Publication No. 2015 / 080291. The standard specific gravity of the obtained PTFE was 2.160. The standard specific gravity (SSG) was measured by the water displacement method according to ASTM D 792 using a sample formed according to ASTM D 4895.

[0158] Synthesis Example 1: Synthesis of Compound 1-1 A nitrogen-purged reaction vessel was charged with 600 mg of sodium hydroxide (FUJIFILM Wako Pure Chemical Industries, Ltd., 15.3 mmol), 30 g of 1,3-bis(trifluoromethyl)benzene (Tokyo Chemical Industry Co., Ltd.), and 10 g of fluoropolyether alcohol terminated at both ends (Solvay, Fomblin D2, 5.1 mmol) and heated and stirred at 70°C for 3 hours. The internal temperature was raised to 65°C, and 5.5 g of triethylene glycol-2-bromoethyl methyl ether (Tokyo Chemical Industry Co., Ltd., 20.4 mmol) was added dropwise from the dropping funnel over 10 minutes, followed by heating and stirring for 6 hours. After returning to room temperature, 5 ml of 1N hydrochloric acid was added to the reaction solution and stirred for 3 hours. This solution was washed four times with pure water, and 2 g of magnesium sulfate was added to the separated organic layer and dried. The magnesium sulfate was removed by filtration, and the volatile matter was distilled off from the treated solution, followed by drying at 100°C for 3 hours to obtain the following compound 1-1 (PFPE-PEG). Compound 1-1 was a liquid at 25°C. Compound 1-1: CH ３ O (CH ２ CH ２ O) ｘ１ CH ２ CF ２ (OCF ２ CF ２ ) ｙ (OCF ２ ) ｚ OCF ２ CH ２ O (CH ２ CH ２ O) ｘ２ CH ３ (x1:4, y: average 12.3, z: average 10.2, x2:4, (CH ２ CH ２ Number average molecular weight of (CH ２ CH ２ Number average molecular weight of O) x2: 176)

[0159] 1. Preparation of solid electrolyte mixture sheet A binder (PTFE) and a sulfide solid electrolyte (LiI-LiBr-Li ２ S-P ２ S ５) and optionally fluoropolyether (PFPE) were added to a cylindrical container and mixed and granulated by rotating on a rotating stand. Here, by varying the amount of PFPE added, multiple solid electrolyte mixtures (compositions) with different volume fractions of PFPE in the mixture were obtained. The obtained solid electrolyte mixture was molded into a bulk form and then rolled to a thickness of about 100 μm to obtain a solid electrolyte sheet (Examples 1 and 2). The amount of PFPE added in each solid electrolyte mixture is as shown in Table 1 below. PFPE has a chemical structure represented by the following formula (I) (m / n is 1.2, number average molecular weight is 5120, terminal R is CF ３ and CF ２ CF ３ are present in an average ratio of 1:0.17) and are liquid at 25°C.

[0160]

[0161] Solid electrolyte mixture sheets were prepared in the same manner as in Examples 1 and 2, except that Compound 1-1 synthesized in Synthesis Example 1 was used instead of PFPE (Examples 3 and 4).

[0162] In Examples 3 and 4, solid electrolyte mixture sheets were prepared in the same manner as in Examples 3 and 4, except that LiTFSI (manufactured by Kishida Chemical Co., Ltd.) was added to Compound 1-1 so that the salt concentration was 5 mass% (Examples 5 and 6).

[0163] Solid electrolyte mixture sheets were prepared in the same manner as in Examples 1 and 2, except that PFPE was not used (Comparative Examples 1 and 2).

[0164] 2. Preparation of the positive electrode mixture: A binder (PTFE), a conductive additive (VGCF), and a sulfide solid electrolyte (LiI-LiBr-Li ２ S-P ２ S ５ ) and a positive electrode active material (LiNi ０．８０ Co ０．１５ Mn ０．０５ O ２) and optionally fluoropolyether (PFPE) were added to a cylindrical container and mixed and granulated by rotating on a rotating stand. Here, by changing the amount of PFPE added, multiple positive electrode mixtures (compositions) with different volume fractions of PFPE in the mixture were obtained. The obtained positive electrode mixture was molded into a bulk shape and then rolled to a thickness of approximately 100 μm to obtain a positive electrode mixture sheet (Examples 7 and 8). The amount of PFPE added in each positive electrode mixture is as shown in Table 2 below. The PFPE used was the same as that used in Examples 1 and 2.

[0165] Positive electrode mixture sheets were prepared in the same manner as in Examples 7 and 8, except that Compound 1-1 synthesized in Synthesis Example 1 was used instead of PFPE (Examples 9 and 10).

[0166] In Examples 9 and 10, a positive electrode mixture sheet was prepared in the same manner as in Examples 9 and 10, except that LiTFSI (manufactured by Kishida Chemical Co., Ltd.) was added to Compound 1-1 so that the salt concentration was 5 mass% (Examples 11 and 12).

[0167] Positive electrode mixture sheets were prepared in the same manner as in Examples 7 and 8, except that PFPE was not used (Comparative Examples 3 and 4).

[0168] 3. Preparation of negative electrode mixture A binder (PVdF), a conductive additive (VGCF), and a sulfide solid electrolyte (LiI-LiBr-Li ２ S-P ２ S ５ The resulting mixture was kneaded using an ultrasonic homogenizer to obtain a negative electrode mixture slurry. The obtained negative electrode mixture slurry was dried to obtain a negative electrode mixture.

[0169] 4. Preparation of solid electrolyte mixture evaluation cell The solid electrolyte mixture sheet was punched out to a diameter of 11.28 mm to obtain an evaluation sample. The thickness of the obtained evaluation sample was measured using a micrometer, and then the evaluation sample was sandwiched between carbon-coated thick foils, and current was collected on both sides with SUS electrodes to prepare a solid electrolyte mixture evaluation cell.

[0170] 5. Evaluation of solid electrolyte mixture

[0049] Resistance was measured by AC impedance spectroscopy using the solid electrolyte mixture evaluation cell prepared as described above. From the obtained Nyquist plot, the resistance value at the real axis intercept at 300 kHz was read, and the ionic conductivity was calculated from this and the thickness of the electrolyte layer.

[0171] 6. Battery Fabrication The solid electrolyte sheet was placed in a cylinder with a diameter of 11.28 mm and subjected to a pressure of 10 kN / cm ２ The negative electrode mixture was placed on one side of the prepared solid electrolyte layer and pressed with a pressure of 10 kN / cm. ２ The sheet was molded under a pressure of 1000 psi. A positive electrode mixture sheet punched to Φ11.28 mm was placed on the opposite side of the negative electrode mixture. An Al foil punched to Φ11.28 mm was placed on the positive electrode side, and a Cu foil punched to Φ11.28 mm was placed on the negative electrode side. The sheets were then restrained at 5 MPa to obtain an electrode body having a configuration of Al foil / positive electrode mixture layer / solid electrolyte layer / negative electrode mixture layer / Cu foil. Current extraction tabs were attached to the Al foil and Cu foil of the electrode body, respectively, to prepare a battery for evaluation.

[0172] 7. Evaluation of Battery Resistance The resistance of the test battery prepared as described above was measured. Specifically, the resistance value of the real axis intercept on the low frequency side of the arc component was read from the Nyquist plot obtained by the AC impedance method, and this was determined as the battery resistance.

[0173] 8. Evaluation Results The results of Comparative Examples 1 and 2 and Examples 1 to 6 are shown in Table 1 below. The evaluation results of ionic conductivity are shown relative to the ionic conductivity of Comparative Example 1 as the reference (100).

[0174]

[0175] The following can be said from the results shown in Table 1. (1) The ionic conductivity of Examples 1, 3, and 5 was higher than that of Comparative Example 1, and that of Examples 2, 4, and 6 was higher than that of Comparative Example 2. This is thought to be because the lubricating effect of the fluoropolyether improved the packing of the solid electrolyte mixture, thereby improving the ionic conductivity. (2) The ionic conductivity of Example 5 was higher than that of Example 3, and that of Example 6 was higher than that of Example 4. This is thought to be because Compound 1-1 can dissolve lithium salt.

[0176] The results of Comparative Examples 3 and 4 and Examples 7 to 12 are shown in Table 2 below. Note that the configurations and manufacturing conditions of the electrolyte layer and negative electrode are common to the Examples and Comparative Examples, and are therefore omitted from Table 2. Furthermore, the evaluation results of the battery resistance are shown relative to the resistance value in Comparative Example 3 as the reference (100).

[0177]

[0178] The results shown in Table 2 suggest the following. (1) The battery resistance was lower in Examples 7, 9, and 11 than in Comparative Example 3, and in Examples 8, 10, and 12 than in Comparative Example 4. This is thought to be because the lubricating effect of the fluoropolyether increased the fluidity of the mixture when molding the positive electrode, resulting in an active material layer with a high packing rate, which reduced the battery resistance. (2) The battery resistance was lower in Example 11 than in Example 9, and in Example 12 than in Example 10. This is because Compound 1-1 can dissolve lithium salt.

[0179] In the above examples, fluoropolyethers having specific chemical structures are exemplified, but the chemical structure of the fluoropolyether is not limited to this. Furthermore, in the above examples, the case where the fluoropolyether is contained in the positive electrode side is exemplified, but the same effect can be expected when the fluoropolyether is contained in the negative electrode side or in the electrolyte layer. Furthermore, the mixture compositions of the positive electrode, electrolyte layer, and negative electrode are not limited to those described above.

[0180] As described above, a composition having the following features can reduce the resistance of an electrochemical device having a sulfide solid electrolyte: - The composition contains a sulfide solid electrolyte, a fluoropolyether, and a fibrillar resin.

Claims

1. A composition comprising a sulfide solid electrolyte, a fluoropolyether and a fibrillar resin.

2. The composition according to claim 1, wherein the fluoropolyether is at least one of the following formulas (1) to (4): (1) R １ -O-Ra １ -Rb １ -O-Ra １ -R １ (2) R ２ -Rb ２ -O-Ra ２ -Rb ２ -R ２ (3) R ３ -Rb ３ -O-Ra ３ -R ３ (4) R ４ -Rb ４ -R ４ (In the formula, Ra １ ~Ra ３ each independently represents a group containing an alkylene unit not containing fluorine and / or an oxyalkylene unit not containing fluorine, １ ~Ra ３ Each oxyalkylene unit is independently —CH ２ CH ２ O- or -CH ２ CH(J)O-, each J is independently an alkyl group or an aryl group, Rb １ ~Rb ４ R is each independently a fluoropolyether group represented by the following formula (5): １ ~R ３ are each independently a hydrogen atom, a hydroxyl group, a fluorine atom, an alkyl group having 1 to 3 carbon atoms, an aryl group, a carboxylic acid group, or a fluoroalkyl group having 1 to 3 carbon atoms; R ４ are each independently a fluorine atom, a hydrogen atom, a hydroxyl group, an aldehyde group, a carboxylic acid group, an alkyl ester group having 1 to 10 carbon atoms, an amide group which may have a substituent, or an amino group which may have a substituent. １ -Rf-O-Rf ２ - (wherein, Rf １ and Rf ２ are each independently an alkylene group having 1 to 16 carbon atoms which may be substituted by a fluorine atom, and Rf is a divalent fluoropolyether group.

3. The above Ra １ ~Ra ３ The composition according to claim 2, wherein each of the groups is independently a polyoxyalkylene group represented by the following formula (Ra-I): -(CH ２ CH ２ O)r-(CH ２ CH (CH ３ ) O) s-(CH ２ CH (CH ２ CH ３ ) O) t-(CH ２ CH(Ph)O)u- (wherein r, s, t and u are each independently an integer of 0 or 1 or more, and r+s+t+u is 4 to 50.) 4. The above Ra １ ~Ra ３ The composition according to claim 2 or 3, wherein the number average molecular weight of is 40 to 4,000.

5. The composition according to any one of claims 2 to 4, wherein each Rf is independently a fluoropolyether group represented by the following formula (Rf-I): Formula (Rf-I): -(OC ６ F １２ ) a-(OC ５ F １０ ) b-(OC ４ F ８ )c-(OC ３ Rc ６ ) d-(OC ２ F ４ ) e-(OCF ２ )f- (In the formula, Rc is each independently a hydrogen atom, a fluorine atom or a chlorine atom; a, b, c, d, e and f are each independently an integer from 0 to 200; the sum of a, b, c, d, e and f is 1 or more; the order of the repeating units to which a, b, c, d, e or f is assigned is arbitrary; and when all Rc are hydrogen atoms or chlorine atoms, at least one of a, b, c, e and f is 1 or more.) 6. The composition according to any one of claims 2 to 5, wherein each Rf is independently a group represented by the following formula (Rf-II) or the following formula (Rf-I-II): Formula (Rf-II): -(OC ３ F ６ ) d-(OC ２ F ４ )e- (wherein, d is an integer of 1 to 200, and e is 0 or 1.) Formula (Rf-I-II): -(OC ４ F ８ )c-(OC ３ F ６ ) d-(OC ２ F ４ ) e-(OCF ２ )f- (In the formula, c and d each independently represent an integer of 0 to 30, e and f each independently represent an integer of 1 to 200, the sum of c, d, e and f is 2 or more, and the order of each repeating unit to which c, d, e or f is added is arbitrary.) 7. The above R １ ~R ３ The composition according to any one of claims 2 to 6, wherein each of the is independently a methyl group, an ethyl group, a trifluoromethyl group, or a pentafluoroethyl group.

8. The composition according to any one of claims 1 to 7, wherein said fibrillating resin is polytetrafluoroethylene.

9. The composition according to any one of claims 1 to 8, wherein said fluoropolyether is liquid at any temperature between 25°C and 80°C.

10. The composition according to any one of claims 1 to 9, wherein the content of the polyalkylene oxide represented by the following formula (6) is less than 20 mass %. (6) R １Ｂ - (OCHR １Ａ (CH ２ ) jCHR ２Ａ ) n-OR ２Ｂ (In the formula, R １Ａ and R ２Ａ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, j is an integer of 0 or 1 to 2, and R １Ｂ and R ２Ｂ are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and n is an integer of 5 to 1000.

11. The composition according to any one of claims 1 to 10, wherein the content of the lithium salt relative to the fluoropolyether is 0.1 to 30% by mass.

12. A mixture for electrochemical devices comprising the composition according to any one of claims 1 to 11.

13. The mixture for electrochemical devices according to claim 12, further comprising a conductive assistant.

14. A mixture sheet for electrochemical devices comprising the mixture for electrochemical devices according to claim 12 or 13.

15. An electrochemical device using the composite sheet for electrochemical devices according to claim 14.

16. A method for producing a composite sheet for electrochemical devices, comprising: a step (1) of mixing a fluoropolyether, a fibrillar resin, and a sulfide solid electrolyte; and a step (2) of rolling the composition obtained in the step (1) into a sheet.

17. The method according to claim 16, wherein the fluoropolyether is at least one of the following formulas (1) to (4), and the fibrillating resin is polytetrafluoroethylene. １ -O-Ra １ -Rb １ -O-Ra １ -R １ (2) R ２ -Rb ２ -O-Ra ２ -Rb ２ -R ２ (3) R ３ -Rb ３ -O-Ra ３ -R ３ (4) R ４ -Rb ４ -R ４ (In the formula, Ra １ ~Ra ３ each independently represents a group containing an alkylene unit not containing fluorine and / or an oxyalkylene unit not containing fluorine, １ ~Ra ３ Each oxyalkylene unit is independently —CH ２ CH ２ O- or -CH ２ CH(J)O-, each J is independently an alkyl group or an aryl group, and Rb １ ~Rb ４ R is each independently a fluoropolyether group represented by the following formula (5): １ ~R ３ are each independently a hydrogen atom, a hydroxyl group, a fluorine atom, an alkyl group having 1 to 3 carbon atoms, an aryl group, a carboxylic acid group, or a fluoroalkyl group having 1 to 3 carbon atoms; R ４ are each independently a fluorine atom, a hydrogen atom, a hydroxyl group, an aldehyde group, a carboxylic acid group, an alkyl ester group having 1 to 10 carbon atoms, an amide group which may have a substituent, or an amino group which may have a substituent. １ -Rf-O-Rf ２ - (wherein, Rf １ and Rf ２ are each independently an alkylene group having 1 to 16 carbon atoms which may be substituted by a fluorine atom, and Rf is each independently a group represented by the following formula (Rf-II) or (Rf-I-II). Formula (Rf-II): -(OC ３ F ６ ) d-(OC ２ F ４ )e- (wherein, d is an integer of 1 to 200, and e is 0 or 1.) Formula (Rf-I-II): -(OC ４ F ８ )c-(OC ３ F ６ ) d-(OC ２ F ４ ) e-(OCF ２ )f- (In the formula, c and d each independently represent an integer of 0 to 30, e and f each independently represent an integer of 1 to 200, the sum of c, d, e and f is 2 or more, and the order of each repeating unit to which c, d, e or f is added is arbitrary.)

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