Composition, mixture for solid state battery, sulfide solid electrolyte layer, electrode layer, and secondary battery

Abstract

To provide a composition capable of reducing resistance of an electrochemical device having a sulfide solid electrolyte, a mixture for a solid battery, a sulfide solid electrolyte layer, an electrode layer, and a secondary battery.SOLUTION: A composition contains at least one of fluoropolyether represented by any one of the following formulae (1) to (3), and a sulfide solid electrolyte. Formula (1): R1-O-Ra1-Rb1-O-Ra1-R1. Formula (2): R2-Rb2-O-Ra2-Rb2-R2, and formula (3): R3-Rb3-O-Ra3-R3.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a composition, a mixture for a solid state battery, a sulfide solid electrolyte layer, an electrode layer, and a secondary battery. [Background technology]

[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 a specific range. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2022-506854 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-062709 Summary of the Invention [Problem to be solved by the invention]

[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 capable of reducing the resistance of an electrochemical device having a sulfide solid electrolyte, a mixture for a solid battery, a sulfide solid electrolyte layer, an electrode layer, and a secondary battery. [Means for solving the problem]

[0007] The present disclosure (1) relates to a polymerizable composition comprising at least one fluoropolyether represented by any one of the following formulas (1) to (3): and a sulfide solid electrolyte. (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 (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, Ra 1 ~Ra 3each oxyalkylene unit is independently —CHCHO— or —CHCH(J)O—; Each J is independently an alkyl group or an aryl group; Rb 1 ~Rb 3 are each independently a fluoropolyether group represented by the following formula (4): R 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)-Rf 1 -Rf-O-Rf 2 - (In the formula, Rf 1 and Rf 2 each independently represents an alkylene group having 1 to 16 carbon atoms which may be substituted with a fluorine atom, Rf is a divalent fluoropolyether group.

[0008] The present disclosure (2) is 1 ~Ra 3 are each independently a polyoxyalkylene group represented by the following formula (Ra-I): (Ra-I): -(CH2CH2O)r(CH2CH(CH3)O)s(CH2CH(CH2CH3)O)t(CH2CH(Ph)O)u- (In the formula, 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.)

[0009] The present disclosure (3) is 1 ~Ra 3 The composition according to the present disclosure (1) or (2), wherein the number average molecular weight of the compound is 40 to 4,000.

[0010] The present disclosure (4) is the composition according to any one of the present disclosures (1) to (3), wherein each Rf is independently a fluoropolyether group represented by the following formula (Rf-I): Formula (Rf-I): -(OC6F 12 )a-(OC5F 10 )b-(OC4F8)c-(OC3Rc6)d-(OC2F4)e-(OCF2)f- (In the formula, each Rc independently represents a hydrogen atom, a fluorine atom, or a chlorine atom, 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 greater than or equal to 1; The order of the repeating units designated by a, b, c, d, e, or f is arbitrary; When all Rc's are hydrogen atoms or chlorine atoms, at least one of a, b, c, e, and f is 1 or greater.

[0011] The present disclosure (5) is the composition according to any one of the present disclosures (1) to (4), wherein each Rf is independently a group represented by the following formula (Rf-II) or the following formula (Rf-I-II): Formula (Rf-II): -(OC3F6)d-(OC2F4)e- (In the formula, d is an integer of 1 to 200, and e is 0 or 1.) Formula (Rf-I-II): -(OC4F8)c-(OC3F6)d-(OC2F4)e-(OCF2)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; The repeating units marked with c, d, e, or f may be arranged in any order.

[0012] The present disclosure (6) is the composition according to the present disclosure (5), wherein each Rf is independently a group represented by the formula (Rf-I-II).

[0013] The present disclosure (7) relates to the R 1 ~R 3are 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), in which the sulfide solid electrolyte is LiI-LiBr-Li2S-P2S5.

[0015] The present disclosure (9) is the composition according to any one of the present disclosures (1) to (8), which contains an alkali metal salt.

[0016] The present disclosure (10) is the composition according to the present disclosure (9), wherein the alkali metal salt is lithium bis(trifluoromethanesulfonimide).

[0017] The present disclosure (11) is the composition according to any one of the present disclosures (1) to (10), wherein the fluoropolyether is liquid at any temperature between 25°C and 80°C.

[0018] The present disclosure (12) is the composition according to any one of the present disclosures (1) to (11), in which the content of the polyalkylene oxide represented by the following formula (5) is less than 20 mass %. (5)R 1B -(OCHR 1A (CH2)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 0 or an integer of 1 to 2, R 1B and R 2B are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, n is an integer from 5 to 1000.

[0019] The present disclosure (13) is a mixture for a solid battery, which contains the composition according to any one of the present disclosures (1) to (12).

[0020] The present disclosure (14) is the solid battery mixture according to the present disclosure (13), which contains a binder.

[0021] The present disclosure (15) is a mixture for a solid battery according to the present disclosure (13) or (14), which contains a conductive additive.

[0022] The present disclosure (16) is a sulfide solid electrolyte layer using the mixture for a solid battery according to any one of the present disclosures (13) to (15).

[0023] The present disclosure (17) is an electrode layer using the mixture for a solid battery according to any one of the present disclosures (13) to (15).

[0024] The present disclosure (18) is a secondary battery including the sulfide solid electrolyte layer according to the present disclosure (16) and the electrode layer according to the present disclosure (17).

[0025] The present disclosure (19) is a secondary battery including the sulfide solid electrolyte layer according to the present disclosure (16).

[0026] The present disclosure (20) is a secondary battery including the electrode layer according to the present disclosure (17).

[0027] The present disclosure (21) is a method for manufacturing a semiconductor device, wherein the electrode layer has an active material layer, In the secondary battery according to the present disclosure (18), the content of the fluoropolyether in the active material layer is 1 to 25% by volume.

[0028] The present disclosure (22) is a method for manufacturing a semiconductor device, wherein the electrode layer has an active material layer, In the secondary battery according to the present disclosure (20), the content of the fluoropolyether in the active material layer is 1 to 25% by volume.

[0029] The present disclosure (23) is the secondary battery according to the present disclosure (21), wherein the content of the fluoropolyether in the active material layer is 1 to 10% by volume.

[0030] The present disclosure (24) is the secondary battery according to the present disclosure (22), wherein the content of the fluoropolyether in the active material layer is 1 to 10% by volume. [Effects of the Invention]

[0031] 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 a solid battery, a sulfide solid electrolyte layer, an electrode layer, and a secondary battery. DETAILED DESCRIPTION OF THE INVENTION

[0032] The present disclosure will be specifically described below.

[0033] <Composition> The present disclosure relates to a composition containing at least one fluoropolyether represented by any one of the following formulas (1) to (3) and a sulfide solid electrolyte. (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 (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, Ra 1 ~Ra 3 each oxyalkylene unit is independently —CHCHO— or —CHCH(J)O—; Each J is independently an alkyl group or an aryl group; Rb 1 ~Rb 3are each independently a fluoropolyether group represented by the following formula (4): R 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)-Rf 1 -Rf-O-Rf 2 - (In the formula, Rf 1 and Rf 2 each independently represents an alkylene group having 1 to 16 carbon atoms which may be substituted with a fluorine atom, Rf is a divalent fluoropolyether group.

[0034] The composition of the present disclosure, having the above-described configuration, can reduce the resistance of an electrochemical device having a sulfide solid electrolyte. Furthermore, while conventional methods tend to increase resistance when the pressing pressure of electrodes or the like is reduced, the composition of the present disclosure can suppress the increase in resistance when the pressing pressure is reduced.

[0035] Ra 1 ~Ra 3 The alkylene unit may be linear or branched, but is preferably linear, and preferably has 1 to 3 carbon atoms.

[0036] Ra 1 ~Ra 3 When the oxyalkylene unit is -CHCH(J)O-, the alkyl group of J may be linear or branched, but is preferably linear. The alkyl group of 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.

[0037] Ra 1 ~Ra 3In the formula (I), the total number of fluorine-free alkylene units and fluorine-free oxyalkylene units is preferably 4 to 50.

[0038] Ra 1 ~Ra 3 Each 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): -(CH2CH2O)r-(CH2CH(CH3)O)s-(CH2CH(CH2CH3)O)t-(CH2CH(Ph)O)u- (In the formula, 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.)

[0039] In the above formula (Ra-I), r is preferably 1 or more, more preferably 2 or more, and is 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 is preferably 20 or less, more preferably 10 or less.

[0040] Ra 1 ~Ra 3 The number average molecular weight of is preferably 40 or more, more preferably 100 or more, and is preferably 4000 or less, more preferably 1000 or less. In this specification, Ra 1 ~Ra 3 The number average molecular weight of 1 This is a value measured by H-NMR.

[0041] Rb 1 ~Rb 3 In the above formula (4), Rf 1 and Rf 2 The alkylene group may be linear or branched, but is preferably linear. Rf 1 and Rf 2 The alkylene group is preferably a fluorine-substituted alkylene group substituted with a fluorine atom. Rf 1 and Rf 2 The alkylene group preferably has 1 to 3 carbon atoms.

[0042] Rb 1 ~Rb 3 In the above formula (4), Rf may have a ring structure.

[0043] Rb 1 ~Rb 3 In the formula (4), Rf is preferably a fluoropolyether group represented by the following formula (Rf-I): Formula (Rf-I): -(OC6F 12 )a-(OC5F 10 )b-(OC4F8)c-(OC3Rc6)d-(OC2F4)e-(OCF2)f- (In the formula, each Rc independently represents a hydrogen atom, a fluorine atom, or a chlorine atom, 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 greater than or equal to 1; The order of the repeating units designated by a, b, c, d, e, or f is arbitrary; When all Rc's are hydrogen atoms or chlorine atoms, at least one of a, b, c, e, and f is 1 or greater.

[0044] Rc is preferably a hydrogen atom or a fluorine atom, and more preferably a fluorine atom, That is, Rf in formula (4) is preferably a perfluoropolyether group.

[0045] It is preferred that a, b, c, d, e and f each independently represent an integer of 0 to 100.

[0046] 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.

[0047] Each repeating unit denoted by a, b, c, d, e, or f may be linear or branched. -(OC6F 12 )- may be, for example, any of -(OCF2CF2CF2CF2CF2CF2CF2)-, -(OCF(CF3)CF2CF2CF2CF2)-, -(OCF2CF(CF3)CF2CF2CF2)-, -(OCF2CF2CF(CF3)CF2CF2)-, -(OCF2CF2CF2CF(CF3)CF2)-, or -(OCF2CF2CF2CF2CF(CF3))-. -(OC5F 10 )- may be, for example, any of -(OCF2CF2CF2CF2CF2)-, -(OCF(CF3)CF2CF2CF2)-, -(OCF2CF(CF3)CF2CF2)-, -(OCF2CF2CF(CF3)CF2)-, and -(OCF2CF2CF2CF(CF3))-. -(OC4F8)- may be, for example, any of -(OCF2CF2CF2CF2)-, -(OCF(CF3)CF2CF2)-, -(OCF2CF(CF3)CF2)-, -(OCF2CF2CF(CF3))-, -(OC(CF3)2CF2)-, -(OCF2C(CF3)2)-, -(OCF(CF3)CF(CF3))-, -(OCF(C2F5)CF2)-, and -(OCF2CF(C2F5))-. -(OC3F6)- (i.e., in the above formula (Rf-I), when all Rc's are fluorine atoms) may be, for example, any of -(OCF2CF2CF2)-, -(OCF(CF3)CF2)-, and -(OCF2CF(CF3))-. -(OC2F4)- may be, for example, either -(OCF2CF2)- or -(OCF(CF3))-.

[0048] Rf may be a group represented by any one of the following formulae (Rf-II) to (Rf-IV). Formula (Rf-II): -(OC3F6)d-(OC2F4)e- (In the formula, d is an integer of 1 to 200, and e is 0 or 1.) Formula (Rf-I-II): -(OC4F8)c-(OC3F6)d-(OC2F4)e-(OCF2)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; The repeating units marked with c, d, e, or f may be arranged in any order. Formula (Rf-I-III): -(R 20 -R 21 )g- (In the formula, R 20 is OCF2 or OC2F4, R 21 are OC2F4, OC3F6, OC4F8, OC5F 10 and OC6F 12 or a combination of two or three groups selected from these groups, g is an integer from 2 to 100. Formula (Rf-I-IV): -(OC6F 12 )a-(OC5F 10 )b-(OC4F8)c-(OC3F6)d-(OC2F4)e-(OCF2)f- (In the formula, e is an integer of 1 to 200, a, b, c, d, and f each independently represent an integer of 0 to 200; The order of the repeating units marked with a, b, c, d, e, or f is arbitrary. Formula (Rf-IV): -(OC6F 12 )a-(OC5F 10)b-(OC4F8)c-(OC3F6)d-(OC2F4)e-(OCF2)f- (wherein f is an integer of 1 to 200, a, b, c, d, and e each independently represent an integer of 0 to 200; The order of the repeating units marked with a, b, c, d, e, or f is arbitrary.

[0049] In the above formula (Rf-II), d is preferably 5 to 200, more preferably 10 to 100, and even more preferably 15 to 50, and may be 25 to 35. The above formula (Rf-II) is preferably a group represented by -(OCF2CF2CF2)d- or -(OCF(CF3)CF2)d-.

[0050] 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 a group represented by -(OCF2CF2CF2CF2)c-(OCF2CF2CF2)d-(OCF2CF2)e-(OCF2)f- or a group represented by -(OC2F4)e-(OCF2)f-, and more preferably a group represented by -(OC2F4)e-(OCF2)f-.

[0051] In the above formula (Rf-I-III), R 20 is preferably OC2F4, and R 21is preferably a group selected from OC2F4, OC3F6 and OC4F8, or a combination of two or three groups independently selected from these groups, more preferably a group selected from OC3F6 and OC4F8. The combination of two or three groups independently selected from OC2F4, OC3F6 and OC4F8 is not particularly limited, and examples thereof include -OC2F4OC3F6-, -OC2F4OC4F8-, -OC3F6OC2F4-, -OC3F6OC3F6-, -OC3F6OC4F8-, -OC4F8OC4F8-, -OC4F8OC3F6-, -OC4F8OC2F4-, -OC Examples include 2F4OC2F4OC3F6-, -OC2F4OC2F4OC4F8-, -OC2F4OC3F6OC2F4-, -OC2F4OC3F6OC3F6-, -OC2F4OC4F8OC2F4-, -OC3F6OC2F4OC2F4-, -OC3F6OC2F4OC3F6-, -OC3F6OC3F6OC2F4-, and -OC4F8OC2F4OC2F4-. 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), OC2F4, OC3F6, OC4F8, OC5F 10 , and OC6F 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 -(OC2F4-OC3F6)g- or -(OC2F4-OC4F8)g-.

[0052] 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.

[0053] 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.

[0054] In Rf, the ratio of e to f (hereinafter referred to as "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 improved. 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.

[0055] Rf is represented by the following formula (Rf-I-VI): -(OCF2CF2CF2)a-(OCF(CF3)CF2)b-(OCF2CF(CF3))c-(OCF2CF2)d-(OCF(CF3))e-(OCF2)f- (In the formula, 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 greater than or equal to 1; The order of the repeating units marked with a, b, c, d, e, or f is arbitrary. It may also be a group represented by the following formula:

[0056] Rf is represented by the following formula (Rf-I-VII): -(OCF2CF2)d-(OCF(CF3))e-(OCF2)f- (In the formula, d, e, and f each independently represent an integer of 0 to 200, the sum of d, e, and f is 1 or greater; The order of the repeating units marked with d, e, or f is arbitrary. When Rf is this group, it is thought that the salt solubility will be improved because the number of ether bonds increases, which makes it easier for cations of the salt to coordinate.

[0057] In Rf, the ratio of d to f (hereinafter referred to as "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 making the d / f ratio 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 making the d / f ratio 0.5 or more, the stability of the compound can be further improved. The larger the d / f ratio, the more improved the stability of the fluoropolyether structure. In this case, the value of the d / f ratio is preferably 0.8 or more.

[0058] 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).

[0059] 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. In this specification, the number average molecular weight of Rf is 19 This is a value measured by F-NMR.

[0060] R 1 ~R 3 The alkyl group and fluoroalkyl group may be linear or branched, but are preferably linear. R 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.

[0061] 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.

[0062] The fluoropolyether is particularly preferably the fluoropolyether represented by the formula (1) above, since 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 that is "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 that is "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, and is preferably 25% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0065] The sulfide solid electrolyte is not particularly limited and may be Li2S-P2S5, Li2S-P2S3, Li2S-P2S3-P2S5, Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, LiI-Li2S-SiS2-P2S5, Li2S-SiS2-Li4SiO4, Li2S-SiS2-Li3PO4, Li3PS4-Li4GeS4, Li 3.4 P 0.6 Si 0.4 S4, Li 3.25 P 0.25 Ge 0.76S4, Li 4-x Ge 1-x P x S4(x=0.6~0.8), Li 4+y Ge 1-y Ga y S4(y=0.2~0.3), LiPSCl, LiCl, Li 7-x-2y PS 6-x-y Cl x (0.8≦x≦1.7, 0 <y≦-0.25x+0.5)、Li 10 SnP2S 12 , LiI-LiBr-Li2S-P2S5, etc., or a mixture of two or more thereof can be used. Among these, LiI-LiBr-Li2S-P2S5 is particularly preferred.

[0066] 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.

[0067] In the composition of the present disclosure, the content of the sulfide solid electrolyte is preferably 75% by mass or more, more preferably 85% by mass or more, and 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, and even more preferably 99% by mass or less.

[0068] The compositions of the present disclosure may include a fibrillar resin. 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, and polytetrafluoroethylene (PTFE). 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.

[0069] The PTFE may be a homopolymer of tetrafluoroethylene (TFE), or may be a modified PTFE containing polymerized units based on TFE (TFE units) and polymerized units based on a modified monomer (hereinafter also referred to as "modified monomer units"). The modified PTFE may contain 99.0% by mass or more of TFE units and 1.0% by mass or less of modified monomer units. Alternatively, the modified PTFE may consist only of TFE units and modified monomer units. The PTFE is preferably the modified PTFE, as it improves the binding force, sheet strength, and flexibility.

[0070] The modified PTFE preferably has a modified monomer unit content of 0.00001 to 1.0% by mass relative to the total polymerized units, in terms of improving binding strength, sheet strength, and flexibility. The lower limit of the modified monomer unit content is more preferably 0.0001% by mass, even more preferably 0.001% by mass, even more preferably 0.005% by mass, and especially preferably 0.010% by mass. The upper limit of the modified monomer unit content is preferably 0.90% by mass, more preferably 0.80% by mass, more preferably 0.50% by mass, even more preferably 0.40% by mass, and even more preferably 0.30% by mass. In this specification, the modified monomer unit means a part of the molecular structure of PTFE that is derived from the modified monomer.

[0071] The content of each of the above-mentioned polymer units can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and X-ray fluorescence analysis depending on the type of monomer.

[0072] The modifying monomer is not particularly limited as long as it is copolymerizable with TFE, and examples thereof include perfluoroolefins such as hexafluoropropylene (HFP), hydrogen-containing fluoroolefins such as trifluoroethylene and vinylidene fluoride (VDF), perhaloolefins such as chlorotrifluoroethylene (CTFE), perfluorovinyl ether, perfluoroallyl ether, (perfluoroalkyl)ethylene, ethylene, etc. The modifying monomer used may be one type or multiple types.

[0073] The perfluorovinyl ether is not particularly limited, and examples thereof include perfluorovinyl ethers represented by the following general formula (A): CF2=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.

[0074] An example of the perfluorovinyl ether is perfluoro(alkyl vinyl ether) [PAVE], where 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.

[0075] 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.

[0076] The perfluorovinyl ether further includes those in which Rff in the general formula (A) is a perfluoro(alkoxyalkyl) group having 4 to 9 carbon atoms, and those in which Rff ...

[0077] [ka]

[0078] (wherein m represents 0 or an integer of 1 to 4), and Rff is a group represented by the following formula:

[0079] [ka]

[0080] (wherein n represents an integer of 1 to 4).

[0081] The (perfluoroalkyl)ethylene [PFAE] is not particularly limited, and examples thereof include (perfluorobutyl)ethylene [PFBE] and (perfluorohexyl)ethylene.

[0082] Examples of perfluoroallyl ethers include those represented by the general formula (B): CF2=CF-CF2-ORff 1 (B) (In the formula, Rff 1 represents a perfluoroorganic group.

[0083] Above Rff 1 is preferably a perfluoroalkyl group having 1 to 10 carbon atoms or a perfluoroalkoxyalkyl group having 1 to 10 carbon atoms. The perfluoroallyl ether is preferably at least one selected from the group consisting of CF2=CF-CF2-O-CF3, CF2=CF-CF2-O-C2F5, CF2=CF-CF2-O-C3F7, and CF2=CF-CF2-O-C4F9, more preferably at least one selected from the group consisting of CF2=CF-CF2-O-C2F5, CF2=CF-CF2-O-C3F7, and CF2=CF-CF2-O-C4F9, and even more preferably CF2=CF-CF2-O-CF2CF2CF3.

[0084] 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.

[0085] 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.

[0086] 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 manufactured by 3M. 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.

[0087] 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 that a mixture sheet having even greater strength can be formed. 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 a fluororesin that has not been 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 considered to be the endothermic peak temperature.

[0088] The above-mentioned PTFE preferably exhibits one or more endothermic peaks in the range of 333 to 347°C in a heat of fusion curve when heated at a rate of 10°C / min using a differential scanning calorimeter (DSC), and the heat of fusion between 290 and 350°C calculated from the heat of fusion curve is 62 mJ / mg or more.

[0089] 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, even more preferably 1.0% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, even more preferably 10% by mass or less.

[0090] In the composition of the present disclosure, the content of the polyalkylene oxide represented by the following formula (5) 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. (5)R 1B -(OCHR 1A (CH2)jCHR 2A )n-OR 2B (In the formula, R1A and R 2A are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, j is 0 or an integer of 1 to 2, R 1B and R 2B are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, n is an integer from 5 to 1000.

[0091] In the composition of the present disclosure, the content of the polyalkylene oxide represented by the above formula (5) 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.

[0092] The composition of the present disclosure may contain an alkali metal salt, particularly a lithium salt, which improves the conductivity of lithium ions.

[0093] Any lithium salt can be used, and specific examples include the following: LiPF6, LiBF4, LiClO4, LiAlF4, LiSbF6, LiTaF6, LiWF7, LiAsF6, LiAlCl4, LiI, LiBr, LiCl, LiB 10 Cl 10 Inorganic lithium salts such as Li2SiF6, Li2PFO3, LiPO2F2, etc.; Lithium tungstates such as LiWOF5; Lithium carboxylates such as HCO2Li, CH3CO2Li, CH2FCO2Li, CHF2CO2Li, CF3CO2Li, CF3CH2CO2Li, CF3CF2CO2Li, CF3CF2CF2CO2Li, CF3CF2CF2CF2CO2Li; Lithium salts having an S=O group, such as FSO3Li, CH3SO3Li, CH2FSO3Li, CHF2SO3Li, CF3SO3Li, CF3CF2SO3Li, CF3CF2CF2SO3Li, CF3CF2CF2CF2SO3Li, lithium methyl sulfate, lithium ethyl sulfate (C2H5OSO3Li), and lithium 2,2,2-trifluoroethyl sulfate; Lithium imide salts such as lithium bis(trifluoromethanesulfonimide) (LiTFSI), lithium bis(monofluorosulfonimide) (LiFSI), LiN(FCO)2, LiN(FCO)(FSO2), LiN(FSO2)2, LiN(FSO2)(CF3SO2), LiN(CF3SO2)2, LiN(C2F5SO2)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(CF3SO2)(FSO2), LiN(CF3SO2)(C3F7SO2), LiN(CF3SO2)(C4F9SO2), and LiN(POF2)2; Lithium methide salts such as LiC(FSO2)3, LiC(CF3SO2)3, LiC(C2F5SO2)3; Other, formula: LiPF 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) (for example, fluorine-containing organic lithium salts such as LiPF3(C2F5)3, LiPF3(CF3)3, LiPF3(iso-C3F7)3, LiPF5(iso-C3F7), LiPF4(CF3)2, LiPF4(C2F5)2), LiPF4(CF3SO2)2, LiPF4(C2F5SO2)2, LiBF3CF3, LiBF3C2F5, LiBF3C3F7, LiBF2(CF3)2, LiBF2(C2F5)2, LiBF2(CF3SO2)2, and LiBF2(C2F5SO2)2, LiSCN, LiB(CN)4, LiB(C6H5)4, Li2(C2O4), LiP(C2O4)3, Li2B 12 F b H 12-b (b is an integer of 0 to 3), etc.

[0094] Among these, LiTFSI, LiFSI, LiPF6, LiBF4, LiSbF6, LiTaF6, LiPO2F2, FSO3Li, CF3SO3Li, LiN(FSO2)2, LiN(FSO2)(CF3SO2), LiN(CF3SO2)2, LiN(C2F5SO2)2, lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropanedisulfonylimide, LiC(FSO2)3, LiC(CF3SO2)3, LiC(C2F5SO2)3, LiBF3CF3, LiBF3C2F5, LiPF3(CF3)3, LiPF3(C2F5)3, and the like are preferred, with LiTFSI, LiFSI, and LiPF6 being particularly preferred.

[0095] 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 a combination of LiPF6 and LiBF4, or a combination of LiPF6 and LiPO2F2, C2H5OSO3Li or FSO3Li, which has the effect of improving high-temperature storage characteristics, load characteristics and cycle characteristics.

[0096] 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. Preferred organic lithium salts include CF3SO3Li, LiN(FSO2), LiN(FSO2)(CF3SO2), LiN(CF3SO2), LiN(C2F5SO2), lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropanedisulfonylimide, LiC(FSO2), LiC(CF3SO2), LiC(C2F5SO2), LiBF3CF3, LiBF3C2F5, LiPF3(CF3), and LiPF3(C2F5)3.

[0097] 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.

[0098] <Solid-state battery mixture> The composition of the present disclosure can reduce the resistance of an electrochemical device, and is therefore useful as a mixture for a solid-state battery, which is an electrochemical device. The present disclosure also relates to a mixture for a solid-state battery comprising the composition of the present disclosure.

[0099] In the solid battery mixture of the present disclosure, the content of the composition of the present disclosure is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, and is preferably 100% by mass or less, even more preferably 95% by mass or less.

[0100] The solid battery mixture of the present disclosure may contain a conductive aid. The mixture for electrochemical devices of the present disclosure may contain a conductive assistant. The conductive additive is not particularly limited, but examples thereof include 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 in any combination and ratio of two or more.

[0101] In the solid battery mixture of 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.

[0102] The solid battery mixture of the present disclosure may contain a binder (binding agent). The binder is not particularly limited, and examples thereof include resin-based polymers such as the above-mentioned fibrillar resins, 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; and EPDM (ethylene-propylene copolymer). Examples of suitable polymers include thermoplastic elastomeric polymers such as styrene-ethylene-butadiene-styrene 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; fluorinated polymers such as polyvinylidene fluoride, vinylidene fluoride copolymers, and tetrafluoroethylene-ethylene copolymers; and polymer compositions with ionic conductivity for alkali metal ions (especially lithium ions). These may be used alone or in any combination and ratio of two or more.

[0103] In the solid battery mixture of the present disclosure, the content of the binder is usually 0.1 to 10 mass %.

[0104] The solid battery mixture of the present disclosure contains a sulfide solid electrolyte, and therefore can be used as a solid electrolyte mixture. Furthermore, by further blending an electrode active material, it can also be used as an electrode mixture.

[0105] The electrode material may be a positive electrode active material or a negative electrode active material.

[0106] 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.

[0107] Examples of the alkali metal-containing transition metal composite oxide include: Formula: M a Mn 2-b M 1 b O4 (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 (wherein at least one metal is 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 (I). Formula:MNi 1-c M 2 c O2 (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 Formula:MCo 1-d M 3 d O2 (Wherein, M is at least one metal selected from the group consisting of Li, Na, and K; 0≦d≦0.5; M 3is 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.

[0108] Among these, MCoO2, MMnO2, MNiO2, MMn2O4, and MNi are the most popular because they can provide high energy density and high output secondary batteries. 0.8 Co 0.15 Al 0.05 O2 or MNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 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 O2 (In the formula, M is at least one metal selected from the group consisting of Li, Na, and K, and M 5 represents at least one element 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, and 0≦k≦0.2.

[0109] Examples of the alkali metal-containing transition metal phosphate compound include compounds represented by the following general formula: M e M 4 f (PO4) g (In the formula, 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.

[0110] The transition metal in the alkali metal-containing transition metal phosphate compound is preferably V, Ti, Cr, Mn, Fe, Co, Ni, Cu, etc. Specific examples include iron phosphates such as LiFePO4, Li3Fe2(PO4)3, and LiFeP2O7, cobalt phosphates such as LiCoPO4, and lithium transition metal phosphate compounds in which a portion of the main transition metal atoms is substituted with other elements such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb, and Si. The lithium-containing transition metal phosphate compound is preferably one having an olivine structure.

[0111] Other examples of the positive electrode active material include lithium-nickel composite oxides. The lithium-nickel composite oxides are represented by the following general formula: Li y Ni 1-x M x O2 (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.

[0112] Other positive electrode active materials include MFePO4 and MNi 0.8 Co 0.2 O2, M 1.2 Fe 0.4 Mn 0.4 O2, MNi 0.5 Mn 1.5 O2, MV3O6, M2MnO3, etc. In particular, M2MnO3, MNi 0.5 Mn 1.5Positive electrode active materials such as O2 are preferable in that their crystal structures do not collapse even when the secondary battery is operated at a voltage exceeding 4.4 V or at a voltage of 4.6 V or higher. Therefore, an electrochemical device such as a secondary battery using a positive electrode material containing the positive electrode active material exemplified above is preferable because the residual capacity hardly decreases and the resistance increase rate hardly changes even when stored at a high temperature, and the battery performance does not deteriorate even when operated at a high voltage.

[0113] As other positive electrode active materials, solid solution materials such as M2MnO3 and M 6 O2 (where M is at least one metal selected from the group consisting of Li, Na, and K, and M 6 is a transition metal such as Co, Ni, Mn, Fe, etc.) can also be mentioned.

[0114] Examples of the solid solution material include, for example, an alkali metal manganate represented by the general formula M x [Mn (1-y) M 7 y O z Here, M in the formula is at least one metal selected from the group consisting of Li, Na, and K, and M 7 consists of at least one metal element other than M and Mn, and includes, for example, one or more elements selected from the group consisting of Co, Ni, Fe, Ti, Mo, W, Cr, Zr, and Sn. Also, the values of x, y, and z in the formula are in the range of 1 < x < 2, 0 ≤ y < 1, and 1.5 < z < 3. Among them, a manganese-containing solid solution material in which LiNiO2 or LiCoO2 is solid-dissolved based on Li2MnO3 such as Li 1.2 Mn 0.5 Co 0.14 Ni 0.14 O2 is preferable in that it can provide an alkali metal ion secondary battery having a high energy density.

[0115] Furthermore, it is preferable to include lithium phosphate in the positive electrode active material, since this improves continuous charging characteristics. Although there are no limitations 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 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.

[0116] 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.

[0117] The positive electrode active material may be used alone or in any combination or ratio of two or more different compositions. In this case, a preferred combination is LiCoO2 and LiNi 0.33 Co 0.33 Mn 0.33 Examples of such a combination include a combination with a ternary system such as O2, a combination of LiCoO2 and LiMn2O4 or a combination in which part of the Mn has been replaced with another transition metal, or a combination of LiFePO4 and LiCoO2 or a combination in which part of the Co has been replaced with another transition metal.

[0118] 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.

[0119] 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; and Li4Ti5O 12 Among them, those containing at least a carbonaceous material and silicon-containing compounds are particularly suitable.

[0120] 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.

[0121] 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 Silicon oxide particles represented by the formula (0.5≦x≦1.6), or a mixture thereof, are preferred. 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.

[0122] 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), where x is preferably 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, and then cooling and precipitating the gas.

[0123] The content of the negative electrode active material is preferably 50 to 90 mass % of the negative electrode mixture in order to increase the 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.

[0124] <Sulfide solid electrolyte layer> The present disclosure also relates to a sulfide solid electrolyte layer using the solid battery mixture of the present disclosure.

[0125] The sulfide solid electrolyte layer of the present disclosure is preferably in the form of a sheet, and the thickness of the sheet 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, 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.

[0126] In the sulfide solid electrolyte layer of the present disclosure, the content of the fluoropolyether is preferably 0.1% by volume or more, more preferably 1% by volume or more, and is preferably 25% by volume or less, more preferably 10% by volume or less.

[0127] <Electrode layer> The present disclosure also relates to an electrode layer using the solid battery mixture of the present disclosure. The electrode layer of the present disclosure may be a positive electrode layer or a negative electrode layer.

[0128] The electrode layer of the present disclosure is preferably in the form of a sheet, and the thickness of the sheet 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, 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.

[0129] The electrode layer of the present disclosure is preferably composed of a current collector and an active material layer containing the solid battery mixture of the present disclosure.

[0130] The content of the fluoropolyether in the active material layer is preferably 0.1% by volume or more, more preferably 1% by volume or more, and is preferably 25% by volume or less, more preferably 10% by volume or less.

[0131] When the electrode layer is a positive electrode layer, examples of the material for the 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. When the electrode layer is a negative electrode layer, examples of the material for the 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.

[0132] Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, expanded metal, punched metal, and foam metal for metal materials, and carbon plate, carbon thin film, and carbon cylinder for carbon materials. Of these, metal foil is preferred. The metal foil may be formed into a mesh shape as appropriate. 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.

[0133] 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.

[0134] The electrode layer may be produced by a conventional method, for example, by laminating an active material layer and a current collector with an adhesive therebetween, followed by vacuum drying.

[0135] The density of the active material layer in the positive electrode layer is preferably 2.50 g / cm 3 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.

[0136] The density of the active material layer in the negative electrode layer is preferably 1.0 g / cm 3 More preferably, 1.2 g / cm 3or 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.

[0137] <Secondary battery> The present disclosure also relates to a secondary battery including the sulfide solid electrolyte layer of the present disclosure and / or the electrode layer of the present disclosure.

[0138] The secondary battery of the present disclosure preferably includes a positive electrode, a negative electrode, etc., and specifically, a lithium ion secondary battery including these is particularly preferred.

[0139] The secondary battery is preferably a solid-state secondary battery. In this specification, the solid secondary battery may be a secondary battery containing a solid electrolyte, and may be a semi-solid secondary battery containing a solid electrolyte and a liquid component as the electrolyte, or an all-solid secondary battery containing only a solid electrolyte as the electrolyte.

[0140] 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.

[0141] The solid secondary battery is preferably a lithium ion battery, and is also preferably a sulfide-based all-solid secondary battery.

[0142] 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.

[0143] The solid secondary battery may include a separator between the positive electrode and the negative electrode, such as a porous membrane of polyethylene or polypropylene, or a nonwoven fabric made of a resin such as polypropylene, or a glass fiber nonwoven fabric.

[0144] 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.

[0145] 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.

[0146] 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. [Example]

[0147] Next, the present disclosure will be described with reference to examples, but the present disclosure is not limited to these examples.

[0148] (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-terminated alcohol (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 over 10 minutes using a dropping funnel. The mixture was then heated and stirred 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 the separated organic layer was dried by adding 2 g of magnesium sulfate. The magnesium sulfate was removed by filtration, and the volatiles were removed from the treated solution. The solution was then further dried 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: CH3O(CH2CH2O) x1 CH2CF2(OCF2CF2) y (OCF2) z OCF2CH2O(CH2CH2O) x2 CH3 (x1:4, y: average 12.3, z: average 10.2, x2:4, (CH2CH2O) x1 Number average molecular weight: 176, (CH2CH2O) x2 Number average molecular weight: 176

[0149] 1.Pressing the Positive Electrode Binder (PVdF), conductive additive (VGCF), sulfide solid electrolyte (LiI-LiBr-Li2S-P2S5), and positive electrode active material (LiNi 0.80 Co 0.15 Mn 0.05O2) and optionally compound 1-1 (PFPE-PEG) were added and kneaded using an ultrasonic homogenizer to obtain a positive electrode composite slurry. The obtained positive electrode composite slurry was applied to an Al foil and dried to obtain a positive electrode for press. Here, by changing the amount of PFPE-PEG added, multiple positive electrodes for press with different volume fractions of PFPE-PEG in the composite were obtained (Examples 1 to 3). The volume fraction of PFPE-PEG in each positive electrode for press is as shown in Table 1 below.

[0150] Positive electrodes for press use (Examples 4 to 6) were prepared in the same manner as in Examples 1 to 3, except that LiTFSI (manufactured by Kishida Chemical Co., Ltd.) was added to Compound 1-1 so that the salt concentration was 5 mass %.

[0151] Positive electrodes for press forming were prepared in the same manner as in Examples 1 to 3, except that PFPE-PEG was not used (Comparative Examples 1 to 3).

[0152] 2. Preparation of Pressed Negative Electrode A binder (PVdF), a conductive additive (VGCF), a sulfide solid electrolyte (LiI-LiBr-Li2S-P2S5), and a negative electrode active material (Si) were added to an organic solvent and kneaded using an ultrasonic homogenizer to obtain a negative electrode composite slurry. The obtained negative electrode composite slurry was applied to a Cu foil and dried to obtain a negative electrode for pressing.

[0153] 3. Preparation of Electrolyte Layer for Pressing A binder (PVdF) and a sulfide solid electrolyte (LiI-LiBr-Li2S-P2S5) were added to an organic solvent and kneaded using an ultrasonic homogenizer to obtain an electrolyte mixture slurry. The obtained electrolyte mixture slurry was applied to an Al foil and dried to obtain an electrolyte layer for pressing.

[0154] 4. Battery Fabrication The positive electrode, negative electrode, and electrolyte layer for pressing were each formed into a rectangular shape. The composite surface of the positive electrode for pressing and the composite surface of the electrolyte layer for pressing were then superimposed, followed by roll pressing at 165 ° C. at the pressure shown in Table 1 below. The Al foil of the electrolyte layer for pressing was then peeled off to obtain a laminate (A) of Al foil, a positive electrode active material layer, and an electrolyte layer. Meanwhile, the composite surface of the negative electrode for pressing and the composite surface of the electrolyte layer for pressing were then superimposed, followed by roll pressing at 25 ° C. at a pressure of 30 kN / cm. The Al foil of the electrolyte layer for pressing was then peeled off to obtain a laminate (B) of Cu foil, a negative electrode active material layer, and an electrolyte layer. The laminate (A) was punched out to a diameter of 11.28 mm, and the laminate (B) was punched out to a diameter of 13.00 mm. An electrolyte layer was further transferred to the laminate (B) using a uniaxial press, and then the laminate (A) and the laminate (B) were superimposed to obtain an electrode body having a configuration of Al foil / positive electrode active material layer / electrolyte layer / negative electrode active material layer / Cu foil. Current extraction tabs were attached to the Al foil and Cu foil of the electrode body, and the electrode body was sealed in a laminate pack using a vacuum lami-sealer to produce a battery for evaluation.

[0155] 5. Battery Resistance Evaluation The resistance of the evaluation 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 resistance of the battery.

[0156] 6. Evaluation Results The results are shown in Table 1 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 1. The evaluation results of the battery resistance are shown relative to the resistance value in Comparative Example 1, which is set as the reference (100.0). The reduction effects of Examples 1 to 6 show the difference from the results of the Comparative Examples, which had the same pressing pressure.

[0157] [Table 1]

[0158] The results shown in Table 1 indicate the following: (1) As shown in Comparative Examples 1 to 3, the lower the pressure applied when molding the positive electrode, the higher the battery resistance. It is believed that when the molding pressure is lowered, the packing ratio of the composite material decreases, resulting in an active material layer with many gaps, which increases the battery resistance. (2) As shown in Comparative Examples 1 to 3 and Examples 1 to 3, when the pressure during molding of the positive electrode was the same, the battery resistance was lower when PFPE-PEG was included in the composite (Examples 1 to 3) than when PFPE-PEG was not included (Comparative Examples 1 to 3). Furthermore, in Examples 1 to 3, the increase in resistance when the molding pressure was lowered was suppressed compared to Comparative Examples 1 to 3. In Examples 1 to 3, the lubricating effect of PFPE-PEG increased the fluidity of the composite when molding the positive electrode, resulting in an active material layer with a high packing ratio, which is thought to have resulted in the lower battery resistance. (3) As shown in Examples 4 to 6, the combined use of Compound 1-1 and a lithium salt results in a more pronounced resistance-reducing effect, because Compound 1-1 can dissolve the lithium salt.

[0159] 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 composite composition of the positive electrode, electrolyte layer, and negative electrode is not limited to those described above.

[0160] As described above, the composition having the following configuration can reduce the resistance of an electrochemical device having a sulfide solid electrolyte. The battery contains at least one fluoropolyether represented by any one of the formulas (1) to (3) and a sulfide solid electrolyte.

Claims

1. At least one fluoropolyether represented by any one of the following formulas (1) to (3), A composition comprising a sulfide solid electrolyte. (1) R1-O-Ra1-Rb1-O-Ra1-R1 (2) R2-Rb2-O-Ra2-Rb2-R2 (3) R3-Rb3-O-Ra3-R3 (In the formula, Ra1 to Ra3 each independently represent a group containing an alkylene unit not containing fluorine and / or an oxyalkylene unit not containing fluorine, The oxyalkylene units Ra1 to Ra3 are each independently —CHCHO— or —CHCH(J)O—, J's are each independently an alkyl group or an aryl group; Rb1 to Rb3 each independently represent a fluoropolyether group represented by the following formula (4): R1 to R3 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) -Rf1-Rf-O-Rf2- (In the formula, Rf1 and Rf2 each independently represent an alkylene group having 1 to 16 carbon atoms which may be substituted with a fluorine atom, Rf is a divalent fluoropolyether group.

2. 2. The composition according to claim 1, wherein Ra1 to Ra3 are each independently a polyoxyalkylene group represented by the following formula (Ra-I): (Ra-I): -(CH2CH2O)r(CH2CH(CH3)O)s(CH2CH(CH2CH3)O)t(CH2CH(Ph)O)u- (In the formula, 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.)

3. 3. The composition according to claim 1, wherein the number average molecular weights of Ra1 to Ra3 are 40 to 4,000.

4. 3. The composition according to claim 1, wherein each Rf is independently a fluoropolyether group represented by the following formula (Rf-I): Formula (Rf-I): -(OC6F12)a-(OC5F10)b-(OC4F8)c-(OC3Rc6)d-(OC2F4)e-(OCF2)f- (In the formula, each Rc independently represents a hydrogen atom, a fluorine atom, or a chlorine atom, 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 greater than or equal to 1; The order of the repeating units assigned with a, b, c, d, e, or f is arbitrary; When all Rc's are hydrogen atoms or chlorine atoms, at least one of a, b, c, e, and f is 1 or more.

5. The composition according to claim 1 or 2, wherein each Rf is independently a group represented by the following formula (Rf-II) or the following formula (Rf-I-II): Formula (Rf-II): -(OC3F6)d-(OC2F4)e- (In the formula, d is an integer of 1 to 200, and e is 0 or 1.) Formula (Rf-I-II): -(OC4F8)c-(OC3F6)d-(OC2F4)e-(OCF2)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; The order of the repeating units marked with c, d, e, or f is arbitrary.

6. The composition according to claim 5, wherein each Rf is independently a group represented by formula (Rf-I-II).

7. 3. The composition according to claim 1, wherein R1 to R3 are each independently a methyl group, an ethyl group, a trifluoromethyl group, or a pentafluoroethyl group.

8. The composition according to claim 1 or 2, wherein the sulfide solid electrolyte is LiI-LiBr-Li2S-P2S5.

9. 3. The composition of claim 1, further comprising an alkali metal salt.

10. 10. The composition of claim 9, wherein the alkali metal salt is lithium bis(trifluoromethanesulfonimide).

11. The composition according to claim 1 or 2, wherein the fluoropolyether is liquid at any temperature between 25°C and 80°C.

12. The composition according to claim 1 or 2, wherein the content of the polyalkylene oxide represented by the following formula (5) is less than 20 mass %: (5) R1B-(OCHR1A(CH2)jCHR2A)n-OR2B (In the formula, R1A and R2A each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, j is 0 or an integer of 1 to 2; R1B and R2B each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; n is an integer from 5 to 1000.

13. A mixture for a solid state battery, comprising the composition according to claim 1 or 2.

14. The solid state battery mixture according to claim 13, further comprising a binder.

15. The solid battery mixture according to claim 13, further comprising a conductive additive.

16. A sulfide solid electrolyte layer using the mixture for a solid battery according to claim 13.

17. An electrode layer using the solid battery mixture according to claim 13.

18. A secondary battery comprising the sulfide solid electrolyte layer according to claim 16 and the electrode layer according to claim 17.

19. A secondary battery comprising the sulfide solid electrolyte layer according to claim 16.

20. A secondary battery comprising the electrode layer according to claim 17.

21. the electrode layer has an active material layer, 19. The secondary battery in accordance with claim 18, wherein the content of said fluoropolyether in said active material layer is 1 to 25% by volume.

22. the electrode layer has an active material layer, 21. The secondary battery according to claim 20, wherein the content of the fluoropolyether in the active material layer is 1 to 25% by volume.

23. 22. The secondary battery according to claim 21, wherein the content of the fluoropolyether in the active material layer is 1 to 10% by volume.

24. 23. The secondary battery in accordance with claim 22, wherein the content of the fluoropolyether in the active material layer is 1 to 10% by volume.

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