Electrolyte for electricity storage device, enhancer, electrolyte solution, and electricity storage device using same

Abstract

The present invention addresses the problem of providing: a substrate; provided are: an electrolyte which is capable of producing an electricity storage device having an excellent balance among solubility in an organic solvent (non-aqueous solvent), charge / discharge efficiency, resistance value at-10 DEG C, cycle characteristics (volume change rate, capacity retention rate, resistance change rate), and high-temperature characteristics; a reinforcing agent; and an electrolyte solution; and an electricity storage device produced using the electrolyte, the reinforcing agent, and the electrolyte solution. And a method for producing the lithium-boron fluoride complex compound for the electrolyte or the enhancer, and a method for producing the lithium complex compound. An electrolyte for an electricity storage device, which contains a lithium-boron fluoride complex compound having a specific substituent.

Description

Technical Field

[0001] The present invention relates to an electrolyte, a reinforcing agent, an electrolytic solution for an electricity storage device, an electricity storage device produced using the same, and a method for producing the same. Background Art

[0002] In recent years, with the popularization of various electronic devices such as portable electronic terminals represented by smart phones, laptops, etc., as well as hybrid vehicles, electric vehicles, etc., secondary batteries have played an important role as their power sources. As these secondary batteries, aqueous solution or non-aqueous electrolyte batteries, and all-solid-state batteries can be cited. Among them, lithium ion secondary batteries using non-aqueous electrolytes with positive and negative electrodes that can contain and release lithium ions, etc., and non-aqueous electrolytes have high energy density at high voltages, excellent safety, and various advantages compared to other secondary batteries in terms of environmental issues.

[0003] In the lithium-ion secondary batteries currently in practical use that use non-aqueous electrolytes, for example, the positive electrode active material uses a composite oxide of lithium and a transition metal, and the negative electrode active material uses a material that can be doped / dedoped with lithium. In order to improve the characteristics, it is required to improve the characteristics of the non-aqueous electrolyte that is responsible for lithium ion transport.

[0004] As such a non-aqueous electrolyte, LiBF dissolved in an aprotic organic solvent was used. 4 、LiPF 6 、LiClO 4 、LiN(SO 2 CF 3 ) 2 、LiN(SO 2 CF 2 CF 3 ) 2 Electrolyte with isoelectric electrolyte.

[0005] It is known that these LiBF 4 、LiPF 6 The non-aqueous electrolyte solution has high conductivity for lithium ion transport and LiBF 4 、LiPF 6 The oxidation decomposition voltage of lithium ion is high, so it is stably at a high voltage, which helps to bring out the characteristics of lithium secondary batteries such as high voltage and high energy density.

[0006] However, nonaqueous electrolytes used in such lithium secondary batteries are required to have high lithium ion conductivity for low resistance, improved cycle characteristics to maintain high capacity even after repeated charge and discharge, initial low resistance characteristics, and maintenance of high characteristics at high temperatures.

[0007] In order to achieve these objects, various improvements have been proposed for the electrolyte contained in the non-aqueous electrolyte, and new proposals have been made for the material itself.

[0008] In addition, lithium-ion secondary batteries and all-solid-state lithium batteries have been developed that use aqueous electrolytes without the worry of battery fires caused by the flammability of organic solvents in non-aqueous electrolytes. Various improvements have been proposed for the solid electrolytes therein, and new proposals have been made for the materials themselves.

[0009] For example, Patent Document 1 proposes a nonaqueous electrolyte solution containing a complex compound represented by the following general formula as an electrolyte. This discloses that the initial resistance characteristics of an electricity storage device can be improved.

[0010] X-(OA(Z)-OB - (Y)(F)M + -) n -R

[0011] (X, Y, Z, and R represent an alkyl group, A represents P=O, and M represents an alkali metal.)

[0012] In addition, Patent Document 2 proposes a compound having the general formula (1): M + PO 3 (F)A - (Where M + A non-aqueous electrolyte solution containing a complex compound having a partial structure represented by (a) is a monovalent metal, and A is a boron atom or a phosphorus atom as an electrolyte. Thus, a non-aqueous electrolyte solution capable of improving the high-temperature charging storage characteristics of an electric storage device, in particular, suppressing the resistance increase during storage, is disclosed.

[0013] Furthermore, Patent Document 3 discloses an electrolyte for a power storage device containing a lithium-containing complex compound represented by the following formula.

[0014] (Li) m (A) n (UF x ) y

[0015] (Li) m (Si) n (O) q (UF x ) y

[0016] (A is O, S, P or N, U is B or P. m and n are 1 to 6, q is 1 to 12, x is 3 or 5, and y is 1 to 6.)

[0017] (Li) m (O) n (B) p(OWF q ) x

[0018] (W is B or P, m, p, x are 1 to 15, n is 0 to 15, q is 3 or 5.)

[0019] (Li) m (B) p (O) n (OR) y (OWF q ) x

[0020] (W is B or P. n is 0 to 15, p, m, x, y are 1 to 12, q is 3 or 5. R is hydrogen, alkyl, etc.)

[0021] (Li) m (O) n (B) p (OOC-(A) z -COO) y (OWF q ) x

[0022] (W is B or P. A is an alkylene group having 1 to 6 carbon atoms. m, p, x, and y are 1 to 20, n is 0 to 15, z is 0 or 1, and q is 3 or 5.)

[0023] The following is disclosed: Based on this electrolyte, a non-aqueous electrolyte with low resistance is obtained, and a storage device such as a lithium ion secondary battery with good initial characteristics and excellent cycle characteristics is obtained. Furthermore, since it itself has excellent lithium ion conductivity, an all-solid-state lithium secondary battery is obtained.

[0024] However, sufficient improvements or new electrolytes have not yet been obtained.

[0025] Prior art literature

[0026] Patent Literature

[0027] Patent Document 1: International Publication No. 2014 / 175225

[0028] Patent Document 2: Japanese Patent Application Publication No. 2020-194771

[0029] Patent Document 3: International Publication No. 2019 / 180945 Summary of the invention

[0030] Problems to be solved by the invention

[0031] The object of the present invention is to provide an electrolyte, a reinforcing agent, an electrolyte solution and an energy storage device made using the same, which can be used to produce an energy storage device having an excellent balance among solubility in an organic solvent (non-aqueous solvent), charge and discharge efficiency, -10°C resistance value, cycle characteristics (volume change rate, capacity retention rate, resistance change rate) and high-temperature characteristics, as well as a lithium-boron fluoride complex compound and a method for producing a lithium complex compound for the above-mentioned electrolyte or reinforcing agent.

[0032] Means for solving problems

[0033] Therefore, in order to solve the above-mentioned problems, the present inventors have discovered a novel electrolyte for a power storage device containing a specific complex compound, and have completed the present invention based on the discovery.

[0034] That is, the present invention is characterized by the following aspects.

[0035] 1. An electrolyte for a power storage device, comprising a complex compound (A), characterized in that:

[0036] The complex compound (A) contains one or more complex compounds represented by the following formula (1).

[0037] [Chemistry 1]

[0038]

[0039] (In formula (1), X 1 is a P(═O) group or a P(═S) group,

[0040] R 1 ~R 3 Each independently represents a group selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, a halogen atom, an alkoxy group, a silyloxy group, a thiosilyl group, and a group represented by the following formula (2), or a group selected from the group consisting of R 1 ~R 3 One of the two groups in the group is an oxygen atom and is bonded to the other to form a ring structure,

[0041] R 1 ~R 3 At least one of them is a group having a structure represented by the following formula (2).

[0042] [Chemistry 2]

[0043]

[0044] (Formula (2) represents an oligomer having a structure in which the repeating units shown in [] are linked, and the linking order of the repeating units is arbitrary,

[0045] l indicates using []l The number of repetitions of the enclosed repeating unit is 1 to 10.

[0046] m represents [] m The number of repetitions of the enclosed repeating unit is a number from 0 to 10.

[0047] n represents the use of [] n The number of repetitions of the enclosed repeating unit is a number from 0 to 10.

[0048] M + is an alkali metal cation or a quaternary ammonium cation,

[0049] Y 1 ~Y 3 are each independently an oxygen atom or a sulfur atom,

[0050] B is a boron atom,

[0051] G is a halogen atom,

[0052] X 2 is a boron atom, a P(═O) group or a P(═S) group,

[0053] Z represents that the preceding and succeeding groups are directly connected, or is a group selected from the group consisting of a substituted or unsubstituted alkylene group, an alkenylene group, a phenylene group, and an alkylene group having an ether group or a thioether group in the main chain,

[0054] R 4 Each is independently a hydrogen atom, an alkyl group, an alkenyl group, a halogen atom, an alkoxy group, a siloxy group, or a thiosilyl group.)

[0055] 2. The electrolyte according to item 1 above, wherein the complex compound has at least one boron halide group.

[0056] 3. The electrolyte according to item 1 above, wherein the complex compound has at least one of the siloxy group and / or the thiosilyl group.

[0057] 4. The electrolyte according to item 1 above, characterized in that

[0058] The above complex compound has:

[0059] at least one boron halide group; and

[0060] At least one of the above-mentioned siloxy group and / or the above-mentioned sulfosilyl group.

[0061] 5. The electrolyte according to item 1 above, wherein the complex compound comprises one or more selected from the group consisting of complex compounds represented by the following formulae (3) to (14).

[0062] [Chemistry 3]

[0063]

[0064] [Chemistry 4]

[0065]

[0066] 6. A reinforcing agent for an electricity storage device, characterized in that it contains the complex compound (A) according to any one of 1 to 5 above.

[0067] 7. An electrolyte for an electricity storage device, comprising at least the complex compound (A) described in any one of 1 to 5 above and an organic solvent, characterized in that:

[0068] The concentration of the alkali metal cation or quaternary ammonium cation derived from the complex compound (A) in the entire electrolyte solution is 0.01 mol / L or more and 2.0 mol / L or less.

[0069] 8. An electrolyte solution for an electricity storage device, comprising at least the complex compound (A) according to any one of 1 to 5 above and an organic solvent, characterized in that:

[0070] The concentration of the complex compound (A) in the entire electrolyte solution is 0.1 mass % or more and 30 mass % or less.

[0071] 9. An electricity storage device produced using the electrolyte described in 7 or 8 above.

[0072] 10. An electricity storage device produced using the electrolyte described in any one of 1 to 5 above and / or the reinforcing agent described in 6 above.

[0073] 11. A solid-state electricity storage device produced using the electrolyte described in any one of 1 to 5 above and / or the reinforcing agent described in 6 above.

[0074] 12. A production method, which is a production method for synthesizing the complex compound (A) described in any one of 1 to 5 above, characterized in that:

[0075] The complex compound (A) contains a P(═O) group or a P(═S) group, and / or a boron halide group,

[0076] The production method comprises step 1: subjecting a boron halide salt (E) and a phosphorus compound (F) to a bonding reaction based on dehalogenation of a silyl group,

[0077] The boron halide salt (E) is a salt composed of an anion having two or more halogen atoms bonded to boron, and an alkali metal cation or a quaternary ammonium cation.

[0078] The phosphorus compound (F) is a compound having a siloxy group or a thiosilyl group bonded to a P(═O) group or a P(═S) group.

[0079] 13. The manufacturing method as described in 12 above is characterized in that, after the above step 1, it also includes one or more steps 2: adding additional reaction raw materials composed of a halogenated boron salt (E) and / or a phosphorus compound (F) to carry out a bonding reaction based on dehalogenation of the silyl group.

[0080] Effects of the Invention

[0081] According to the present invention, it is possible to obtain electrolytes, reinforcing agents, electrolyte solutions for producing energy storage devices having an excellent balance among solubility in organic solvents (non-aqueous solvents), charge and discharge efficiency, -10°C resistance value, cycle characteristics (volume change rate, capacity retention rate, resistance change rate), and high-temperature characteristics, and energy storage devices produced using the same, as well as lithium-boron fluoride complex compounds and lithium complex compounds for the above-mentioned electrolytes or reinforcing agents. DETAILED DESCRIPTION

[0082] The above-mentioned present invention will be described in more detail below. The description of the technical features described below is an example of the embodiment of the present invention, and the present invention is not limited to these contents unless it exceeds the gist of the present invention.

[0083] <Electrolytes>

[0084] The electrolyte of the present invention is an electrolyte for a power storage device and contains a specific complex compound (A).

[0085] [Complex compound (A)]

[0086] The complex compound (A) in the present invention is a complex compound used for an electrolyte for an electricity storage device, and preferably contains one or more complex compounds represented by the following formula (1).

[0087] [Chemistry 5]

[0088]

[0089] (In formula (1), X 1 is a P(═O) group or a P(═S) group,

[0090] R 1 ~R 3 Each independently represents a group selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, a halogen atom, an alkoxy group, a silyloxy group, a thiosilyl group, and a group represented by the following formula (2), or a group selected from the group consisting of R 1 ~R 3One of the two groups in the group is an oxygen atom and is bonded to the other to form a ring structure,

[0091] R 1 ~R 3 At least one of them is a group having a structure represented by the following formula (2).

[0092] [Chemistry 6]

[0093]

[0094] (Formula (2) represents an oligomer having a molecular structure in which the repeating units shown in [] are linked together, and the linking order of the repeating units is arbitrary,

[0095] l indicates using [] l The number of repetitions of the enclosed repeating unit is 1 to 10.

[0096] m represents [] m The number of repetitions of the enclosed repeating unit is a number from 0 to 10.

[0097] n represents the use of [] n The number of repetitions of the enclosed repeating unit is a number from 0 to 10.

[0098] M + is an alkali metal cation or a quaternary ammonium cation,

[0099] Y 1 ~Y 3 are each independently an oxygen atom or a sulfur atom,

[0100] B is a boron atom,

[0101] G is a halogen atom,

[0102] X 2 is a boron atom, a P(═O) group or a P(═S) group,

[0103] Z represents that the preceding and succeeding groups are directly connected, or is a group selected from the group consisting of a substituted or unsubstituted alkylene group, an alkenylene group, a phenylene group, and an alkylene group having an ether group or a thioether group in the main chain,

[0104] R 4 Each is independently a hydrogen atom, an alkyl group, an alkenyl group, a halogen atom, an alkoxy group, a siloxy group, or a thiosilyl group.)

[0105] Here, the halogenated boron group refers to a group in which at least one halogen atom is bonded to a boron atom.

[0106] Furthermore, the complex compound (A) more preferably has at least one siloxy group and / or thiosilyl group.

[0107] Furthermore, the complex compound (A) more preferably has at least one halogenated boron group and at least one siloxy group and / or silylthio group.

[0108] In the above formula (1), M + Specific examples of the alkali metal cation or quaternary ammonium cation represented by include Li + 、Na + , K + , Rb + , Cs + 、Fr + NH 4 + Among these, Li is preferred + NH 4 + .

[0109] R 1 ~R 3 , R 4 The alkyl groups in are each independently preferably linear or cyclic alkyl groups having 1 to 8 carbon atoms. Specific examples thereof include methyl, ethyl, propyl, butyl, hexyl, cyclopropyl, cyclobutyl, cyclohexyl, hydroxyethyl, trifluoromethyl, and hexafluoroethyl.

[0110] R 1 ~R 3 , R 4 The alkenyl groups in are each independently an alkenyl group having 2 to 5 carbon atoms. Specific examples thereof include ethenyl, propenyl, butenyl, and heptenyl.

[0111] As G, R 4 Specific examples of the halogen atom in include F, Cl, Br, I, and At. Among these, F and Cl are preferred from the viewpoint of stable bonding with a phosphorus atom or a boron atom.

[0112] R 1 ~R 3 , R 4 The alkoxy groups in are each independently preferably alkoxy groups having 2 to 5 carbon atoms. Specific examples thereof include methoxy, ethoxy, and butoxy groups.

[0113] As R 1 ~R 3 , R 4 The silyloxy group in the above-mentioned group includes trimethylsilyloxy, triethylsilyloxy, triisopropylsilyloxy, butyldimethylsilyloxy, tributylsilyloxy, trimethoxysilyloxy, triethoxysilyloxy and tributoxysilyloxy groups.

[0114] As R 1 ~R 3 , R 4 Examples of the thiosilyl group include trimethylthiosilyl, triethylthiosilyl, triisopropylthiosilyl, butyldimethylthiosilyl, tributylthiosilyl, trimethoxythiosilyl, triethoxythiosilyl and tributoxythiosilyl.

[0115] As a use[] m The repeating unit of -Y 2 Z in -CO-Z-CO- represents a state where CO and CO are directly bonded, or is a group selected from the group consisting of a substituted or unsubstituted alkylene group, an alkenylene group, a phenylene group, and an alkylene group having an ether group or a thioether group in the main chain.

[0116] Specific examples of Z include alkylene groups having 1 to 12 carbon atoms, alkenylene groups having 2 to 8 carbon atoms containing an unsaturated bond, phenylene groups, ether groups having 2 to 6 carbon atoms containing oxygen in the main chain, and thioether groups having 2 to 6 carbon atoms containing sulfur in the main chain.

[0117] And, as -Y 2 Specific examples of CO-Z-CO- include -Y 2 CO-CO-, -Y 2 CO-(CH 2 )-CO-、-Y 2 CO-(CH 2 ) 2 -CO-, -Y 2 CO-(CH 2 ) 3 -CO-, -Y 2 CO-(CH 2 ) 4 -CO-, -Y 2 CO-(CH 2 ) 8 -CO-, -Y 2 CO-(CH=CH)-CO-, -Y 2 CO-(C 6 H 4 )-CO-、-Y 2 CO-(CH 2 OCH 2 )-CO-、-Y 2 CO-(CH 2 CH 2 OCH 2 CH 2 )-CO-、-Y 2 CO-(CH 2SCH 2 )-CO-、-Y 2 CO-(CH 2 CH 2 SCH 2 CH 2 )-CO-, etc.

[0118] Specific examples of the complex compound (A) represented by the above formula (1) include complex compounds represented by the following formulas (3) to (14) and complex compounds containing a P(═O) group or a P(═S) group and / or a boron halide group.

[0119] The electrolyte of the present invention preferably contains one or more complex compounds (A) selected from the group consisting of the above.

[0120] [Chemistry 7]

[0121]

[0122] [Chemistry 8]

[0123]

[0124] The above formulas (3), (4), and (14) show that O and B - bonded to form a ring structure.

[0125] <Method for producing complex compound (A)>

[0126] The method for producing the complex compound (A) in the case where the complex compound (A) is a complex compound containing a P(═O) group or a P(═S) group and / or a boron halide group will be described.

[0127] The complex compound containing a P(═O) group or a P(═S) group and / or a boron halide group can be synthesized by a method including the following step 1, or a method including step 1 and one or more steps 2 in sequence.

[0128] (Process 1)

[0129] A step of performing a bonding reaction between the boron halide salt (E) and the phosphorus compound (F) by dehalogenating a silyl group.

[0130] (Process 2)

[0131] After the above step 1, an additional reaction raw material consisting of a boron halide salt (E) and / or a phosphorus compound (F) is added to carry out a bonding reaction by dehalogenation of the silyl group.

[0132] The above-mentioned dehalogenation silyl reaction is carried out in the absence of a solvent, but a solvent may be appropriately used as necessary.

[0133] In addition, by controlling the reaction temperature, the dehalogenation silyl reaction can be effectively carried out. The reaction temperature is not particularly limited as long as it is a temperature at which the dehalogenation silyl reaction can be effectively carried out. For example, the reaction temperature can be selected in the range of 10°C to 150°C according to the use of a solvent, and if it is in the range of 20°C to 120°C, the reaction can be suitably promoted. In addition, from the aspect of easy control of the reaction rate, the range of 40°C to 100°C is more preferred, but is not limited to these conditions.

[0134] The molar ratio of the boron atom in the boron halide salt (E) to the silyl group in the phosphorus compound (F) in step 1 [boron atom of (E) / silyl group of (F)] can be appropriately selected according to the chemical structure of the obtained complex compound (A) and is not particularly limited.

[0135] For example, the molar ratio [boron atom of (E) / silyl group of (F)] is preferably 0.2 to 5, more preferably 0.3 to 3.0. If the molar ratio [boron atom of (E) / silyl group of (F)] is less than the above range, the unreacted silyl group increases, and the solubility of the complex compound (A) is likely to decrease. If it is greater than the above range, the unreacted boron halide salt (E) increases, which may reduce the life performance of the battery.

[0136] In step 2, the amount of the boron halide salt (E) or phosphorus compound (F) added can be appropriately selected according to the chemical structure of the complex compound (A) to be obtained. The type, amount and order of addition of the boron halide salt (E) or phosphorus compound (F) are not particularly limited.

[0137] For example, the molar ratio of the silyl group in the additional phosphorus compound (F) or the boron atom in the additional boron halide salt (E) to the unreacted boron atom in the boron halide salt (E) or the unreacted silyl group in the phosphorus compound (F) in step 1 [{additional silyl group (F) + addition of boron atom (E)} / {unreacted boron atom (E) + unreacted silyl group (F)}] is preferably 0.2 to 5, more preferably 0.3 to 3.0.

[0138] The molar ratio [boron atom (E) / silyl group (F)] in all steps including step 1 and step 2 is, for example, preferably 0.2 to 5.0, more preferably 0.3 to 3.0.

[0139] (Boron halide salt (E))

[0140] The boron halide salt (E) is a salt composed of an anion having two or more halogen atoms bonded to boron and an alkali metal cation or a quaternary ammonium cation, and capable of undergoing a dehalogenation silylation reaction.

[0141] Examples of the boron halide salt (E) include complex salts containing a functional group of a dihalide or trihalide boron, tetrahalide borate, monohalide phosphate, dihalide phosphate, hexahalide phosphate, etc., but are not limited thereto.

[0142] Specific examples of the boron halide salt (E) include tetrahalogenated borate, lithium oxide·bis(trihalide boron) salt, lithium sulfide·bis(trihalide boron) salt, oxalate·trihalide boron complex salt, maleate·trihalide boron complex salt, fumarate·trihalide boron complex salt, citrate·trihalide boron complex salt, adipate·trihalide boron complex salt, glutarate·trihalide boron complex salt, succinate·trihalide boron complex salt, boron trihalide complex salts, tartrate·boron trihalide complex salts, malonate·boron trihalide complex salts, glycolate·boron trihalide complex salts, diglycolate·boron trihalide complex salts, thiodiacetate·boron trihalide complex salts, thiodipropionate·boron trihalide complex salts and other carboxylic acid complex salts, phosphinate·boron trihalide complex salts, dimethylphosphinate·boron trihalide complex salts, difluorophosphate·boron trihalide complex salts and other phosphinates Phosphonic acid complex salts such as acid complex salts, phosphonate·boron trihalide complex salts, methylphosphonate·boron trihalide complex salts, vinylphosphonate·boron trihalide complex salts, fluorophosphate·boron trihalide complex salts, phosphoric acid complex salts such as phosphate·boron trihalide complex salts, methylphosphonate·boron trihalide complex salts, ethylphosphonate·boron trihalide complex salts, condensed phosphoric acid complex salts such as diphosphate·boron trihalide complex salts, polyphosphate·boron trihalide complex salts, monothiophosphate·boron trihalide complex salts, dithiophosphate·boron trihalide complex salts, trithiophosphate·boron trihalide complex salts, tetrathiophosphate·boron trihalide complex salts, and reaction products thereof with phosphorus compounds (F) containing anions having two or more halogen atoms bonded to boron, etc., but are not limited to these.

[0143] As the halogen, fluorine is preferred, and as the cation, lithium cation and sodium ion are preferred. Specific examples in this case include lithium tetrafluoroborate, lithium oxide·bis(boron trifluoride) salt, lithium sulfide·bis(boron trifluoride) salt, lithium tetrafluoroborate salt, lithium oxalate·bis(boron trifluoride) complex salt, lithium maleate·bis(boron trifluoride) complex salt, lithium fumarate·bis(boron trifluoride) complex salt, lithium citraconic acid·bis(boron trifluoride) complex salt, lithium aconitate·bis(boron trifluoride) complex salt, diethylthioate, and the like. Lithium bis(boron trifluoride) complex salt, lithium thiopropionate bis(boron trifluoride) complex salt, lithium adipate bis(boron trifluoride) complex salt, lithium glutarate bis(boron trifluoride) complex salt, lithium succinate bis(boron trifluoride) complex salt, lithium tartrate bis(boron trifluoride) complex salt, lithium malonate bis(boron trifluoride) complex salt, lithium glycolate bis(boron trifluoride) complex salt, lithium diglycolate bis(boron trifluoride) complex salt The invention also includes, but is not limited to, lithium phosphite·tri(boron trifluoride) complex salts, lithium borate·tri(boron trifluoride) complex salts, lithium phosphate·tri(boron trifluoride) complex salts, lithium monothiophosphate·tri(boron trifluoride) complex salts, lithium dithiophosphate·tri(boron trifluoride) complex salts, lithium trithiophosphate·tri(boron trifluoride) complex salts, lithium tetrathiophosphate·tri(boron trifluoride) complex salts, lithium phosphinate·boron trifluoride complex salts, lithium dimethylphosphinate·boron trifluoride complex salts, lithium difluorophosphate·boron trifluoride complex salts, lithium fluorophosphate·boron trifluoride complex salts, lithium phosphonate·bis(boron trifluoride) complex salts, lithium methylphosphonate·bis(boron trifluoride) complex salts, lithium vinylphosphonate·bis(boron trifluoride) complex salts, and reaction products thereof with a phosphorus compound (F) containing an anion having two or more halogen atoms bonded to boron.

[0144] Among these, lithium sulfide·bis(boron trifluoride) complex salt, lithium oxide·bis(boron trifluoride) complex salt, lithium tetrafluoroborate salt, lithium oxalate·bis(boron trifluoride) complex salt, lithium maleate·bis(boron trifluoride) complex salt, lithium citraconic acid·bis(boron trifluoride) complex salt, lithium adipate·bis(boron trifluoride) complex salt, lithium thiodiacetate·bis(boron trifluoride) complex salt, lithium borate·tri(boron trifluoride) complex salt, lithium difluorophosphate·boron trifluoride complex salt, lithium fluorophosphate·tri(boron trifluoride) complex salt, lithium bis ... Boron fluoride complex salts, lithium phosphonate·bis(boron trifluoride) complex salts, lithium methylphosphonate·bis(boron trifluoride) complex salts, lithium vinylphosphonate·bis(boron trifluoride) complex salts, lithium phosphate·tri(boron trifluoride) complex salts, lithium monothiophosphate·tri(boron trifluoride) complex salts, lithium dithiophosphate·tri(boron trifluoride) complex salts, lithium trithiophosphate·tri(boron trifluoride) complex salts, lithium tetrathiophosphate·tri(boron trifluoride) complex salts and reaction products thereof with phosphorus compounds (F).

[0145] (Phosphorus compound (F))

[0146] The phosphorus compound (F) is a compound having a siloxy group or a thiosilyl group bonded to a P(═O) group or a P(═S) group. The compound preferably has two or more of the siloxy group or the thiosilyl group.

[0147] Specific examples of the phosphorus compound (F) include bis(trimethylsilyl)vinylphosphonate, tri(trimethylsilyl)phosphate, trimethylsilyl phosphinate, trimethylsilyl dimethylphosphinate, bis(trimethylsilyl)phosphonate, bis(trimethylsilyl)allylphosphonate, hexa(trimethylsilyl)diphosphate, tri(trimethylsilyl)polyphosphate, tri(trimethylsilyl)monothioate, tri(trimethylsilyl)phosphodithioate, tri(trimethylsilyl)phosphotrithioate, tri(trimethylsilyl)tetrathioate, and reaction products of these with a halogenated boron salt (E) having a siloxy group or a silylthio group bonded to a P(═O) group or a P(═S) group, but are not limited thereto.

[0148] Among these, bis(trimethylsilyl)vinylphosphonate, bis(trimethylsilyl)phosphonate, tris(trimethylsilyl)phosphate, hexa(trimethylsilyl)diphosphate, tris(trimethylsilyl)polyphosphate and the like are preferred.

[0149] <Enhancer>

[0150] In the present invention, the enhancer is a compound that imparts effects of improving the charge and discharge efficiency of a battery, extending the life of the battery, and reducing the resistance.

[0151] The enhancer of the present invention can be used together with the electrolyte of the present invention.

[0152] Furthermore, the enhancer of the present invention may be used together with a lithium-based electrolyte that is not the electrolyte of the present invention.

[0153] Furthermore, the reinforcing agent of the present invention can be used in combination with a general reinforcing agent. As long as the general reinforcing agent maintains good mutual relationship, it can be used in any ratio. There is no limitation here. For example, the content of the reinforcing agent of the present invention in all reinforcing agents contained in the battery is preferably 0.1 mass % to 100 mass %, more preferably 0.2 mass % to 70 mass %.

[0154] Specific examples of the general-purpose reinforcing agent include, for example, sulfur-containing compounds, cyclic acid anhydrides, nitrile compounds, isocyanate compounds, etc., but are not limited to these.

[0155] Examples of the sulfur-containing compound include 1,3-propane sultone (PS), propylene sultone, ethylene sulfite, hexahydrobenzo[1,3,2]dioxazolothiophene-2-oxide (also called 1,2-cyclohexanediol cyclic sulfite), 5-vinyl-hexahydro-1,3,2-benzodioxythiol-2-oxide, 1,4-butanediol dimethanesulfonate, 1,3-butanediol dimethanesulfonate, methylene methane disulfonic acid, ethylene methane disulfonic acid, N,N-dimethylmethanesulfonamide, N,N-diethylmethanesulfonamide, divinyl sulfone, and 1,2-bis(vinylsulfonyl)methane.

[0156] Examples of the cyclic acid anhydride include glutaric anhydride, maleic anhydride, citraconic anhydride, glutaconic anhydride, itaconic anhydride, succinic anhydride, diglycolic anhydride, cyclohexanedicarboxylic anhydride, cyclopentanetetracarboxylic anhydride, 4-cyclohexene-1,2-dicarboxylic anhydride, 3,4,5,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, phenylsuccinic anhydride, 2-phenylglutaric anhydride, phthalic anhydride, pyromellitic anhydride, fluorosuccinic anhydride, and the like. anhydride, tetrafluorosuccinic anhydride and other carboxylic anhydrides; 1,2-ethanedisulfonic anhydride, 1,3-propanedisulfonic anhydride, 1,4-butanedisulfonic anhydride, 1,2-benzenedisulfonic anhydride, tetrafluoro-1,2-ethanedisulfonic anhydride, hexafluoro-1,3-propanedisulfonic anhydride, octafluoro-1,4-butanedisulfonic anhydride, 3-fluoro-1,2-benzenedisulfonic anhydride, 4-fluoro-1,2-benzenedisulfonic anhydride, 3,4,5,6-tetrafluoro-1,2-benzenedisulfonic anhydride, etc.

[0157] Examples of the nitrile compound include valeronitrile, octanonitrile, decanenitrile, dodecanonitrile, crotononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelonitrile, suberonitrile, and glutaronitrile.

[0158] Examples of the isocyanate compound include alkyl isocyanates such as methyl isocyanate, ethyl isocyanate, propyl isocyanate, isopropyl isocyanate, butyl isocyanate, and tert-butyl isocyanate; cycloalkyl isocyanates such as cyclohexyl isocyanate; allyl isocyanate, propargyl isocyanate, monomethylene diisocyanate, dimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, 1,4-diisocyanato-2-butene, methyl isocyanate, 1,4-diisocyanato-2-butene, 1,4-diisocyanato-3-butene; Compounds such as phenylene diisocyanate, xylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-diisocyanatocyclohexane, dicyclohexylmethane-4,4'-diisocyanate, bicyclo[2.2.1]heptane-2,5-diylbis(methyl isocyanate), bicyclo[2.2.1]heptane-2,6-diylbis(methyl isocyanate), isophorone diisocyanate, carbonyl diisocyanate, 1,4-diisocyanatobutane-1,4-dione, and trimethylhexamethylene diisocyanate.

[0159] <Electrolyte>

[0160] The electrolytic solution of the present invention is a liquid for an electricity storage device containing an electrolyte and an organic solvent (non-aqueous solvent), and may further contain a reinforcing agent.

[0161] The electrolytic solution of the present invention may contain the complex compound (A) as an electrolyte and / or a reinforcing agent.

[0162] Furthermore, the electrolytic solution of the present invention may contain an electrolyte and / or a reinforcing agent other than the complex compound (A).

[0163] The electrolyte contains cations, which preferably include lithium cations, sodium cations or quaternary ammonium cations, more preferably include lithium cations or sodium cations, and particularly preferably include lithium cations.

[0164] Specific examples of electrolytes other than the complex compound (A) include LiPF 6 , LiBF 4 、LiN(FSO 2 ) 2 、LiN(CF 3 SO 2 ) 2 、LiN(C 2 F 5 SO 2 ) 2 、LiN(CF 3 SO 2 )(C 2 F 5 SO 2 ) or LiN(CF 3 SO 2 )(C 4 F 9 SO 2 ) etc., but are not limited to these.

[0165] The concentration of all cations in the whole electrolyte, especially all lithium cations, is preferably 0.1 mol / L or more and 5.0 mol / L or less, more preferably 0.7 mol / L or more and 2.5 mol / L or less. If the concentration of alkali metal cations or quaternary ammonium cations in the whole electrolyte is lower than the above range, it is easy to become difficult to have sufficient charge and discharge characteristics. Even if it is higher than the above range, the internal resistance is easy to rise, and the charge and discharge characteristics are not improved much.

[0166] The concentration of all cations derived from the complex compound (A), especially lithium cations, in the entire electrolyte is preferably 0.01 mol / L to 3.0 mol / L, more preferably 0.1 mol / L to 2.0 mol / L.

[0167] If the concentration of all cations derived from the complex compound (A), especially lithium cations, in the electrolyte is lower than the above range, the protection of the electrode surface of the power storage device is likely to be insufficient. Even if it is higher than the above range, the lithium ion conductivity of the electrolyte is not much improved.

[0168] In addition, the mass % of the complex compound (A) in the entire electrolyte is preferably 0.01 mass % to 30 mass %, more preferably 0.1 mass % to 20 mass %. If the mass % of the complex compound (A) in the entire electrolyte is lower than the above range, the surface protection of the electrode of the storage device is likely to become insufficient, and even if it is higher than the above range, the lithium ion conductivity of the electrolyte is not much improved.

[0169] [Organic solvents]

[0170] As the organic solvent for the electrolyte solution of the present invention, various organic solvents can be used.

[0171] For example, an aprotic polar solvent can be preferably used.

[0172] In aprotic polar solvent, from the aspect that improves ion conductivity, more preferably use carbonate-based solvents such as cyclic carbonates, linear carbonates, further preferably use cyclic carbonates and linear carbonates in combination.In addition, as cyclic carbonates, preferably use saturated cyclic carbonates and unsaturated cyclic carbonates especially, contain 3 kinds of carbonates.

[0173] When cyclic carbonates and / or chain carbonates are used, other nonaqueous solvents such as lactones, sulfones, ethers, nitriles, chain carboxylates, chain glycol ethers, fluorinated ethers, and phosphoric acid esters may be further added as necessary.

[0174] The volume ratio of cyclic carbonates / chain carbonates in the electrolyte can be used arbitrarily as long as the lithium ion conductivity can be ensured to be sufficiently high. There is no particular limitation. For example, the volume ratio of saturated cyclic carbonates / chain carbonates is preferably 10 / 90 to 70 / 30, more preferably 20 / 80 to 50 / 50.

[0175] In addition, as the cyclic carbonates, unsaturated cyclic carbonates can be used.

[0176] The content of the unsaturated cyclic carbonate is preferably 0.01% by volume to 10% by volume, more preferably 0.1% by volume to 5% by volume, based on the total amount of the organic solvent.

[0177] If cyclic carbonates are less than above-mentioned scope, then dissociation degree, the solubility as electrolyte complex compound are easily reduced, and the ionic conductivity of electrolyte is easily reduced. On the contrary, if more than above-mentioned scope, then electrolyte is easily to become high viscosity, easily solidifies at low temperatures, and therefore easily is difficult to obtain sufficient charge-discharge characteristics.

[0178] If the linear carbonate is less than the above-mentioned scope, the electrolyte easily becomes high viscosity, easily solidifies at low temperatures, and is therefore easy to be difficult to obtain sufficient charge-discharge characteristics. On the contrary, if more than the above-mentioned scope, the dissociation degree, the solubility of the complex compound as the electrolyte are easily reduced, so the ionic conductivity of the electrolyte is easily reduced.

[0179] In addition, if unsaturated cyclic carbonate is less than above-mentioned scope, then be difficult to form good coating on negative electrode surface, so cycle characteristic is easily reduced.On the contrary, if more than above-mentioned scope, then for example easily produce gas by electrolyte when high temperature is preserved, the pressure in the storage device easily rises etc., easily becomes practical unpreferable state.

[0180] As the specific example of aprotic polar solvent, cyclic carbonates, chain carbonates, lactones, sulfones, cyclic ethers, chain ethers, nitriles, chain carboxylates, chain glycol ethers, fluorine-containing ethers, phosphorus-containing compounds, dimethyl sulfoxide, ethylene dichloride, chlorobenzene, nitrobenzene can be enumerated. They can be used alone or in combination of two or more.

[0181] As the specific example of cyclic carbonates, ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, trifluoromethyl ethylene carbonate, fluoroethylene carbonate and 4,5-difluoroethylene carbonate etc. can be enumerated. Among these, preferably ethylene carbonate, propylene carbonate, fluoroethylene carbonate. When using propylene carbonate, stable electrolyte can be obtained in a wide temperature range. These specific compounds can use one or be used in combination of more than two.

[0182] As linear carbonates, for example, linear carbonates with 3 to 9 carbon atoms can be enumerated, and as specific examples, ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, methyl propyl carbonate, dipropyl carbonate, methyl butyl carbonate, dibutyl carbonate, ethyl propyl carbonate and methyl trifluoroethyl carbonate etc. can be enumerated. In the above, propyl group can be each independently n-propyl, or isopropyl, and butyl group can be each independently any one of n-butyl, isobutyl and tert-butyl. Among these, ethyl methyl carbonate, dimethyl carbonate and diethyl carbonate are preferred. These specific compounds can use one or more than two kinds in combination.

[0183] Specific examples of the unsaturated cyclic carbonates include vinylene carbonate derivatives and alkenylethylene carbonate.

[0184] Specific examples of the vinylene carbonate derivatives include vinylene carbonate, fluorovinylene carbonate, methyl vinylene carbonate, fluoromethyl vinylene carbonate, ethyl vinylene carbonate, propyl vinylene carbonate, butyl vinylene carbonate, dimethyl vinylene carbonate, diethyl vinylene carbonate, and dipropyl vinylene carbonate.

[0185] Specific examples of alkenyl ethylene carbonate include 4-vinyl ethylene carbonate, 4-vinyl-4-methyl ethylene carbonate, 4-vinyl-4-ethyl ethylene carbonate, 4-vinyl-4-n-propyl ethylene carbonate, etc. These specific compounds can be used alone or in combination of two or more.

[0186] Examples of cyclic carboxylic acid esters (lactones) include cyclic carboxylic acid esters having 3 to 9 carbon atoms, such as γ-butyrolactone, γ-valerolactone, γ-caprolactone, and ε-caprolactone. Among them, γ-butyrolactone and γ-valerolactone are more preferred. These specific compounds can be used alone or in combination of two or more.

[0187] Examples of chain carboxylic acid esters include chain carboxylic acid esters having 3 to 9 carbon atoms, and specific examples include methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, isopropyl propionate, n-butyl propionate, isobutyl propionate, and tert-butyl propionate. Among them, ethyl acetate, methyl propionate, and ethyl propionate are preferred. These specific compounds may be used alone or in combination of two or more.

[0188] Examples of the chain glycol ethers include chain glycol ethers having 3 to 6 carbon atoms, and specific examples thereof include dimethoxymethane, dimethoxyethane, diethoxymethane, diethoxyethane, ethoxymethoxymethane, ethoxymethoxyethane, etc. Among them, dimethoxyethane and diethoxyethane are more preferred. These specific compounds may be used alone or in combination of two or more.

[0189] Specific examples of the fluorinated ethers include 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2,3,3,3-pentafluoropropyl ether, ethoxy-2,2,2-trifluoroethoxy-ethane, etc. These specific compounds may be used alone or in combination of two or more.

[0190] Specific examples of sulfones include dimethyl sulfone, diethyl sulfone, ethyl methyl sulfone, methyl propyl sulfone, sulfolane, 2-methylsulfolane, 3-methylsulfolane and the like.

[0191] Specific examples of the cyclic ethers include tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, dioxolane, 4-methyldioxolane, and the like.

[0192] Specific examples of the chain ethers include dimethyl ether and the like.

[0193] Specific examples of nitriles include acetonitrile, succinonitrile, adiponitrile, and benzonitrile.

[0194] Specific examples of amides include N,N-dimethylformamide and dimethylacetamide.

[0195] Specific examples of the phosphorus-containing compound include diethyl vinyl phosphate, allyl diethyl phosphate, propargyl diethyl phosphate, trivinyl phosphate, triallyl phosphate, tripropargyl phosphate, diallyl ethyl phosphate, dipropargyl ethyl phosphate, 2-acryloyloxyethyl diethyl phosphate, and tris(2-acryloyloxyethyl)phosphate.

[0196] <Electrical Storage Devices>

[0197] The electricity storage device of the present invention is an electricity storage device produced using the electrolytic solution of the present invention, or an electricity storage device produced using the electrolyte and / or the reinforcing agent of the present invention.

[0198] The power storage device of the present invention may be any of a liquid power storage device, a semi-solid power storage device, and a solid power storage device.

[0199] Specific examples of the power storage device of the present invention include various power storage devices such as lithium ion secondary batteries, electric double layer capacitors, and hybrid batteries in which one of the positive electrode or the negative electrode is a battery and the other is a double layer.

[0200] The shape of the power storage device of the present invention is not particularly limited, and may be various shapes such as a cylindrical shape, a square shape, an aluminum laminate shape, a coin shape, and a button shape.

[0201] The power storage device of the present invention is produced by using the electrolyte, electrolyte solution, reinforcing agent, etc. of the present invention, and thus has low resistance, good initial characteristics, cycle characteristics, and excellent high-temperature characteristics.

[0202] Furthermore, the electricity storage device of the present invention may be produced by using in combination an electrolyte, an electrolyte solution, a reinforcing agent, and the like other than the electrolyte, the electrolyte solution, and the reinforcing agent of the present invention.

[0203] Hereinafter, a lithium ion secondary battery will be described as an example.

[0204] A lithium-ion secondary battery is a secondary battery that is charged and discharged by the movement of lithium ions between a positive electrode and a negative electrode, and is composed of a positive electrode, a negative electrode, a separator, an electrolyte (electrolyte solution), and the like.

[0205] (negative electrode)

[0206] Examples of the structure of the negative electrode include a structure in which a negative electrode active material is formed on a current collector such as copper foil, expanded metal, carbon material, or a composite material thereof.

[0207] As the negative electrode active material constituting the negative electrode, there can be cited carbon materials capable of being doped / dedoped with lithium ions, metallic lithium, lithium-containing alloys, or silicon, silicon alloys, tin, tin alloys capable of being alloyed with lithium, tin oxide capable of being doped / dedoped with lithium ions, silicon oxide, transition metal oxides capable of being doped / dedoped with lithium ions, transition metal nitrogen compounds capable of being doped / dedoped with lithium ions, and mixtures thereof.

[0208] In order to improve the adhesion of the negative electrode active material to the current collector, for example, a polyvinylidene fluoride-based binder, a latex-based binder, etc. may be contained, and as a conductive aid, carbon black, amorphous carbon whisker, carbon nanofiber, etc. may be contained.

[0209] Carbon materials constituting the negative electrode active material include, for example, pyrolytic carbons, cokes (asphalt coke, needle coke, petroleum coke, etc.), graphites, sintered organic polymer compounds (products obtained by sintering and carbonizing phenolic resins, furan resins, etc. at an appropriate temperature), carbon fibers, activated carbon, graphite (natural graphite, artificial graphite, carbon-coated graphite, graphite-coated graphite, resin-coated graphite, etc.), and the like.

[0210] The carbon material is particularly preferably a carbon material having a (002) plane spacing (d002) of 0.340 nm or less as measured by an X-ray diffraction method.

[0211] And, the preferred true density is 1.70 g / cm 3 The above graphite or a highly crystalline carbon material having properties similar thereto.

[0212] By using these carbon materials for the negative electrode, the energy density of the non-aqueous electrolyte power storage device can be increased.

[0213] Furthermore, as the carbon material, there can be used: a carbon material containing boron; a carbon material coated with a metal such as gold, platinum, silver, copper, Sn, Si, or a carbon material coated with a salt such as a magnesium salt or a calcium salt, etc. These carbon materials can be used alone or in combination of two or more.

[0214] In addition, when silicon, silicon alloys, tin, tin alloys, tin oxide, silicon oxide, transition metal oxides that can be doped / dedoped with lithium ions, etc. that can be alloyed with lithium are used, the theoretical capacity per unit weight is higher than that of the above-mentioned carbon materials, and they are suitable materials.

[0215] (positive electrode)

[0216] Examples of the structure of the positive electrode include a structure in which a positive electrode active material is formed on a current collector such as a foil made of aluminum, titanium or stainless steel, or a porous metal mesh, a carbon material, or a composite material thereof.

[0217] The positive electrode active material constituting the positive electrode can be formed of various materials capable of charge and discharge, such as lithium-containing transition metal oxides, lithium-containing transition metal composite oxides using one or more transition metals, transition metal oxides, transition metal sulfides, metal oxides, olivine-type lithium metal salts, etc.

[0218] For example, LiCoO 2 、LiNiO 2 、LiMn 2 O 4 、LiMnO 2 Wait x MO 2 (herein, M is one or more transition metals, x is a value that varies depending on the charge and discharge state of the storage device, and is generally 0.05≤x≤1.20) and a composite oxide of lithium and one or more transition metals (lithium transition metal composite oxide); a metal composite oxide in which a part of the transition metal atoms that will become the main body of these lithium transition metal composite oxides are replaced by other metals such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, Yb, etc.; FeS 2 、TiS 2 、V 2 0 5 、MoO 3 、MoS 2 Chalcogenides of transition elements or polymers such as polyacetylene and polypyrrole.

[0219] Among them, materials such as lithium transition metal composite oxides that can be doped and dedoped with Li or metal composite oxides in which a part of transition metal atoms is substituted with other metals are preferred.

[0220] In addition, a material having a composition different from that of the material constituting the main positive electrode active material may be attached to the surface of the positive electrode active material. Examples of the material attached to the surface include metal oxides, metal sulfides, metal carbonates, and the like.

[0221] Specific examples of the metal oxide include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, and bismuth oxide.

[0222] Specific examples of the metal sulfide include lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, and aluminum sulfate.

[0223] Specific examples of the metal carbonate include carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate.

[0224] In order to improve the adhesion of the positive electrode active material to the collector, for example, a polyvinylidene fluoride-based binder or a latex-based binder may be contained. In order to improve the electron conductivity in the positive electrode, carbon black, amorphous whiskers, graphite, carbon nanofibers, etc. may be contained.

[0225] (Diaphragm)

[0226] The separator is preferably a membrane that electrically insulates the positive electrode from the negative electrode and is permeable to lithium ions.

[0227] Specific examples of the separator include porous films such as microporous polymer films.

[0228] As the microporous polymer film, a porous polyolefin film is preferred, and specifically, a porous polyethylene film, a porous polypropylene film, or a multilayer film of a porous polyethylene film and a polypropylene film is preferred.

[0229] In addition, a polymer electrolyte may be used as the separator. As the polymer electrolyte, for example, a polymer substance in which a lithium salt is dissolved, a polymer substance swollen with an electrolyte solution, etc. may be used, but the present invention is not limited to these.

[0230] Example

[0231] <Synthesis of Raw Materials>

[0232] [Production Example 1]

[0233] Under argon atmosphere, add 500 ml of methanol and 20 g of lithium oxide (Li 2 O), making slurry.

[0234] While cooling, BF 3 / methanol complex solution (a solution with a molar ratio of 1 / 2) was added, and the mixture was stirred at 25°C for 3 hours to obtain a reaction solution.

[0235] Methanol was removed from the obtained reaction solution using an evaporator, and then the solution was washed three times with dibutyl ether and dried under reduced pressure to obtain 75 g of lithium oxide-boron trifluoride complex salt (LiF 3 BOBF3 Li).

[0236] [Production Examples 2 to 10]

[0237] The boron trifluoride complex salts of Production Examples 2 to 10 were prepared in the same manner as in Production Example 1 except that the lithium oxide in Production Example 1 was changed to the compounds and addition amounts shown in Table 1, respectively.

[0238] [Table 1]

[0239]

[0240] <Battery Production>

[0241] A battery for evaluating an electrolytic solution containing the electrolyte or the additive of the present invention was prepared as follows.

[0242] (Production of positive electrode)

[0243] In the positive electrode active material (LiNi 0.8 Mn 0.1 Co 0.1 O 2 ) N-methylpyrrolidone was added to the positive electrode mixture prepared by mixing in the following proportions to prepare a paste.

[0244] Polyvinylidene fluoride 2.0g

[0245] Acetylene black 2.5g

[0246] Positive active material 95.5g

[0247] Then, the obtained paste was applied to both surfaces of an aluminum foil current collector having a thickness of 18 μm, and after the solvent was removed by drying, the paste was rolled using a roll press to obtain a positive electrode.

[0248] (Production of negative electrode)

[0249] The following materials were mixed and slurry was prepared using water as a dispersion medium.

[0250] Artificial graphitized carbon powder 95.8g

[0251] Styrene butadiene rubber (SBR) 2.0g

[0252] Carboxymethyl cellulose 2.2g

[0253] The slurry obtained above was applied to both surfaces of a copper foil having a thickness of 12 μm, and after the solvent was removed by drying, the slurry was rolled using a roll press to obtain a negative electrode.

[0254] (Production of battery cells)

[0255] A flat rolled electrode group was prepared by winding the positive electrode and negative electrode obtained above with a 23 μm thick separator (F23DHA manufactured by Toray Battery Separator Film) interposed therebetween and placed in a case (rectangular parallelepiped shape of 50 mm in length×40 mm in width×2.0 mm in thickness) to prepare a battery cell.

[0256] (Manufacturing of lithium-ion secondary batteries)

[0257] Using the battery cell produced as described above, a lithium ion secondary battery (laminated battery) was produced in the following steps.

[0258] 1) Pour 1.0 g of electrolyte into the injection port of the battery cell, reduce the pressure, and seal the injection port.

[0259] 2) While the sealed battery cell was kept at 25° C., the battery was charged to 4.2 V at 20 mA and then discharged to 3.0 V at 20 mA.

[0260] 3) The internal gas of the battery cell is decompressed and removed to obtain a battery.

[0261] <Various Evaluation Methods>

[0262] [Initial charge and discharge efficiency]

[0263] The battery cell prepared above, which had been filled and sealed, was charged by flowing a current of 20 mA in an atmosphere of 25° C. until the voltage of 0 V reached 4.2 V.

[0264] Then, while the voltage was maintained at 4.2 V, charging was continued until the current value reached 4 mA, and the total value of the current value consumed until the current value reached 4 mA was taken as the initial charge capacity value.

[0265] Next, the charged power storage device was discharged to 3.0 V by passing a current of 20 mA in an atmosphere of 25° C., and the total value of the current value consumed until reaching 3.0 V was taken as the initial discharge capacity value.

[0266] Then, the initial charge and discharge efficiency (%) was calculated from the following formula.

[0267] Initial charge and discharge efficiency (%) = (initial discharge capacity / initial charge capacity) × 100

[0268] [-10℃ resistance value]

[0269] The lithium ion secondary battery prepared above was charged to SOC (State of Charge) 50% at 25°C, and discharged at 0.2C rate for 10 seconds at -10°C. The voltage after 10 seconds of discharge was measured to determine the DC resistance.

[0270] Then, in the same procedure, the voltage after discharging at 0.5C, 1.0C, and 2.0C rates for 10 seconds was measured in an atmosphere of -10°C, and the DC resistance was calculated.

[0271] [Volume change rate]

[0272] The volume value of the lithium ion secondary battery produced as described above in an uncharged state was measured in an atmosphere at 25° C. and was taken as an initial volume value.

[0273] Next, the battery was charged to 4.2 V at a rate of 0.2 C and left in an atmosphere of 60° C. for 4 weeks while maintaining the charged state.

[0274] Then, the battery was discharged at a rate of 0.2 C to 3.0 V in an atmosphere of 25° C., and the volume value of the lithium ion secondary battery was measured as the volume value after high-temperature storage.

[0275] Then, the volume change rate (%) was calculated from the following formula.

[0276] Volume change rate (%) = (volume value after high temperature storage / initial volume value) × 100

[0277] [Capacity maintenance rate]

[0278] The lithium ion secondary battery prepared above was charged to 4.2 V at 1 C rate in an atmosphere of 45° C. and then discharged to 3.0 V at 1 C rate in the same atmosphere. This was regarded as the first cycle, and the discharge capacity value was regarded as the initial capacity value.

[0279] Next, under the same conditions, charge and discharge were repeated 200 times, and the discharge capacity value at the 200th cycle was taken as the post-cycle capacity value.

[0280] Then, the capacity retention rate (%) was calculated by the following formula.

[0281] Capacity retention rate (%) = (capacity value after cycle / initial capacity value) × 100

[0282] [Resistance change rate]

[0283] The lithium ion secondary battery prepared above was charged to SOC (State of Charge) 50% at 25° C., and discharged at rates of 0.2C, 0.5C, 1.0C, and 2.0C for 10 seconds, and the DC resistance was measured as the initial resistance.

[0284] Next, the battery was charged to 4.2 V at 1 C rate in an atmosphere of 45° C., and then discharged to 3.0 V at 1 C rate in the same atmosphere. This was regarded as one cycle. After repeating this cycle 200 times, the DC resistance value was measured as the resistance value after the cycle.

[0285] Then, the resistance change rate was calculated from the following formula.

[0286] Resistance change rate (%) = (resistance value after cycle / initial resistance value) × 100

[0287] <<Experiment 1: Synthesis of complex compounds>>

[0288] <Synthesis 1 of Complex Compound (A)>

[0289] [Example 1]

[0290] (Process 1)

[0291] 18.2 g of lithium sulfide·bis(boron trifluoride) complex salt as boron fluoride lithium salt (C) was dissolved in 200 ml of methyl ethyl carbonate in an Erlenmeyer flask under a nitrogen atmosphere and cooled to prepare a lithium sulfide·bis(boron trifluoride) / methyl ethyl carbonate solution.

[0292] Then, 25.2 g of bis(trimethylsilyl)vinylphosphonate as a phosphorus compound (D) was added to the lithium sulfide·bis(boron trifluoride) / ethyl methyl carbonate solution prepared above with stirring, and after completion of the addition, the mixture was stirred for 3 hours while maintaining at 80° C. to obtain a reaction solution.

[0293] (concentrate)

[0294] Next, ethyl methyl carbonate was removed from the reaction solution obtained above using an evaporator, and the mixture was washed three times with dibutyl ether and dried under reduced pressure to obtain 22 g of a complex compound (A1) represented by the following formula (3) (vinylphosphonic acid / lithium sulfide·bis(boron trifluoride) condensation salt).

[0295] [Chemistry 9]

[0296]

[0297] [Example 2]

[0298] 16.6 g of lithium oxide·bis(boron trifluoride) complex salt was used as the boron fluoride lithium salt (C), and 31.4 g of tri(trimethylsilyl) phosphate was used as the phosphorus compound (D). Except for this, the same operation as Example 1 was carried out to obtain 25 g of the complex compound (A2) ((trimethylsilyl) phosphate / lithium oxide·bis(boron trifluoride) condensation salt) represented by the following formula (4).

[0299] [Chemistry 10]

[0300]

[0301] [Example 3]

[0302] (Process 1)

[0303] 18.8 g of lithium tetrafluoroborate as a boron fluoride lithium salt (C) was dissolved in 200 ml of methyl ethyl carbonate in an Erlenmeyer flask under a nitrogen atmosphere, and the mixture was cooled to obtain a lithium tetrafluoroborate / methyl ethyl carbonate solution.

[0304] Then, 31.4 g of tris(trimethylsilyl) phosphate as a phosphorus compound (D) was added to the lithium tetrafluoroborate / ethyl methyl carbonate solution obtained above with stirring, and the mixture was stirred for 1 hour while maintaining the temperature at 50° C., thereby obtaining a reaction solution 1.

[0305] (Process 2)

[0306] 16.6 g of lithium oxide·bis(boron trifluoride) complex salt as boron fluoride lithium salt (C) was dissolved in 100 ml of ethyl methyl carbonate, and the obtained solution was added to the reaction solution 1 obtained in step 1 at normal pressure in small amounts at a time, and the reaction was carried out under reduced pressure. This operation was repeated several times, and the entire amount was added to carry out the reaction under reduced pressure. Then, the mixture was stirred for 2 hours while being maintained at 50° C., and then maintained at 80° C. for 3 hours to obtain a reaction solution 2.

[0307] (concentrate)

[0308] Next, ethyl methyl carbonate was removed by an evaporator, and the mixture was washed three times with dibutyl ether and dried under reduced pressure to obtain 32 g of a complex compound (A3) represented by the following formula (5) (lithium phosphate·bis(boron trifluoride) / lithium oxide·bis(boron trifluoride) condensation salt).

[0309] [Chemistry 11]

[0310]

[0311] [Examples 4 to 12]

[0312] The same operation as in Example 3 was carried out except that the boron fluoride lithium salt (C) and the phosphorus compound (D) in steps 1 and 2 were changed to the contents and reaction conditions described in Tables 2 and 3, respectively, to obtain 39 g of complex compound (A4) (lithium phosphate·bis(boron trifluoride) / lithium oxalate·bis(boron trifluoride) condensation salt), 41 g of complex compound (A5) (lithium phosphate·bis(boron trifluoride) / lithium maleate·bis(boron trifluoride) condensation salt), 42 g of complex compound (A6) (lithium phosphate·bis(boron trifluoride) / lithium thiodiacetate·bis(boron trifluoride) condensation salt), and 42 g of complex compound (A7) (lithium phosphate·bis(boron trifluoride) / lithium thiodiacetate·bis(boron trifluoride) condensation salt) represented by the following formulas (6) to (14), respectively. / lithium borate·tri(boron trifluoride) condensation salt) 52g, complex compound (A8) (lithium phosphate·bis(boron trifluoride) / lithium phosphate·tri(boron trifluoride) condensation salt) 55g, complex compound (A9) (lithium phosphate·bis(boron trifluoride) / lithium monothiophosphate·tri(boron trifluoride) condensation salt) 56g, complex compound (A10) (lithium phosphate·bis(boron trifluoride) / lithium dithiophosphate·tri(boron trifluoride) condensation salt) 60g, complex compound (A11) (bis(trimethylsilyl)lithium phosphate·(boron trifluoride) condensation salt) 49g, complex compound (A12) (lithium phosphate·boron trifluoride / lithium oxalate·bis(boron trifluoride) condensation salt) 30g.

[0313] [Chemistry 12]

[0314]

[0315] [Chemistry 13]

[0316]

[0317] [Table 2]

[0318]

[0319] [Table 3]

[0320]

[0321] <<Experiment 2: Evaluation of complex compound (A) as electrolyte>>

[0322] <Other electrolyte non-compatibility systems>

[0323] [Example 13]

[0324] (Preparation of Electrolyte)

[0325] A mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and vinylene carbonate (VC) (volume ratio = 30:69:1) and the complex compound (A3) obtained above are added in a manner such that the lithium cation concentration is 1.5 mol / L, mixed in the following mass ratio, and uniformly dissolved to prepare an electrolyte solution.

[0326] Complex compound (A3) 12.8 parts by mass

[0327] Mixed solvent 87.2 parts by mass

[0328] Since the volume of the obtained electrolytic solution was 0.0836 L, the mass concentration of the electrolyte (complex compound (A3)) in the electrolytic solution was calculated as follows.

[0329] Mass concentration: 12.8 / 0.0836=153g / L

[0330] The complex compound (A3) is represented by the following formula (5) and has a molecular weight of 408. Four lithium cations are generated from one molecule. Therefore, the molar concentration of lithium cations derived from the complex compound (A3) in the electrolyte solution is calculated as follows.

[0331] Molar concentration of lithium cations from complex compound (A3): (12.8 / 408)×4 / 0.0836=1.5 mol / L

[0332] [Chemistry 14]

[0333]

[0334] (Battery production and evaluation)

[0335] The above-mentioned lithium ion secondary battery was produced using the electrolyte solution obtained above, and the initial charge and discharge efficiency and -10°C resistance value were evaluated.

[0336] The manufacturing specifications and evaluation results are shown in Table 3 below.

[0337] [Examples 14 to 19, Comparative Example 1]

[0338] Except having changed the complex compound (A3) into the complex compound (A) and mass parts shown in Table 4, it carried out similarly to Example 13, and evaluated similarly.

[0339] [Table 4]

[0340]

[0341] <<Experiment 3: Evaluation of complex compounds as enhancers>>

[0342] <Other strengthening agent non-combination system>

[0343] [Example 20]

[0344] (Preparation of Electrolyte)

[0345] A mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and vinylene carbonate (VC) (volume ratio = 30:68:2) and LiPF 6 , and a complex compound (A1) as a reinforcing agent were mixed in the following mass ratio and uniformly dissolved to prepare an electrolyte solution.

[0346] LiPF 6 12.3 parts by mass

[0347] Complex compound (A1) 2.0 parts by mass

[0348] Mixed solvent 85.7 parts by mass

[0349] The volume of the obtained electrolytic solution was 0.0827 L, and therefore the mass concentration of each electrolyte in the electrolytic solution was calculated as follows.

[0350] LiPF 6 Mass concentration: 12.3 / 0.827=149g / L

[0351] Mass concentration of complex compound (A1): 2 / 0.827 = 24 g / L

[0352] The complex compound (A1) is represented by the following formula (3) and has a molecular weight of 250. Two lithium cations are generated from one molecule. Therefore, the molar concentration of lithium cations derived from the complex compound (A1) in the electrolyte solution is calculated as follows.

[0353] Molar concentration of lithium cations from complex compound (A1): (2 / 250)×2 / 0.0827=0.16 mol / L

[0354] [Chemistry 15]

[0355]

[0356] Similarly, LiPF 6 The molecular weight of LiPF is 152, and one lithium cation is generated from one molecule. Therefore, the amount of LiPF in the electrolyte is 6 The molar concentration of lithium cations is calculated as follows.

[0357] From LiPF 6 The molar concentration of lithium cations: (12.3 / 152)×1 / 0.0827=0.98 mol / L

[0358] (Battery production and evaluation)

[0359] After the lithium ion secondary battery was produced using the electrolyte solution obtained above, the volume value of the battery in an uncharged state was measured in an atmosphere at 25° C. and was taken as the initial volume value.

[0360] Next, the battery was charged to 4.2 V at a rate of 0.2 C, and kept in a charged state at 60° C. for 4 weeks. Then, the battery was discharged to 3.0 V at a rate of 0.2 C at 25° C. Similarly, the volume value of the battery was measured at 25° C. as the volume value after high-temperature storage.

[0361] Then, the volume change rate, capacity retention rate, and resistance change rate were evaluated.

[0362] The manufacturing specifications and evaluation results are shown in Table 5 below.

[0363] [Examples 21 to 25, Comparative Example 2]

[0364] Except having changed the enhancer into the compound and mass part described in Table 5, it carried out similarly to Example 20, and evaluated similarly.

[0365] [Table 5]

[0366]

[0367] <Other Enhancer Combination Systems>

[0368] [Example 26]

[0369] (Preparation of Electrolyte)

[0370] A mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and vinylene carbonate (VC) (volume ratio = 30:69:1) and LiPF 6 , and the complex compound (A1) as a reinforcing agent and 1,3-propane sultone were mixed and dissolved in the following ratio to prepare an electrolyte solution.

[0371] LiPF 6 12.3 parts by mass

[0372] Complex compound (A1) 1.0 parts by mass

[0373] 1,3-Propane sultone 1.0 parts by mass

[0374] Mixed solvent 85.7 parts by mass

[0375] The volume of the obtained electrolytic solution was 0.827 L, and therefore the mass concentration of each electrolyte in the electrolytic solution was calculated as follows.

[0376] LiPF 6 Mass concentration: 12.3 / 0.0827=149g / L

[0377] Mass concentration of complex compound (A1): 1.0 / 0.0827=12 g / L

[0378] The complex compound (A1) is represented by the following formula (3) and has a molecular weight of 250. Two lithium cations are generated from one molecule. Therefore, the molar concentration of lithium cations derived from the complex compound (A1) in the electrolyte solution is calculated as follows.

[0379] Molar concentration of lithium cations from complex compound (A1): (1.0 / 250)×2 / 0.827=0.1 mol / L

[0380] [Chemistry 16]

[0381]

[0382] Similarly, LiPF 6 The molecular weight of LiPF is 152, and one lithium cation is generated from one molecule. Therefore, the amount of LiPF in the electrolyte is 6 The molar concentration of lithium cations is calculated as follows.

[0383] From LiPF 6 The molar concentration of lithium cations: (12.3 / 152)×1 / 0.827=0.98 mol / L

[0384] (Battery production and evaluation)

[0385] A battery was produced using the electrolyte solution obtained above, and the initial resistance was measured in an atmosphere of 25°C.

[0386] Then, in an atmosphere of 45° C., the battery was first charged to 4.2 V at a rate of 1 C, and then discharged to 3.0 V at a rate of 1 C. The discharge capacity was measured, and the first discharge capacity was defined as the initial capacity.

[0387] Next, similarly, charge and discharge were repeated 200 times between 3.0 V and 4.2 V, the discharge capacity was measured, and the capacity retention rate after 200 cycles was calculated.

[0388] Then, the resistance value was measured in an atmosphere at 25° C., and the resistance change rate after 200 cycles was calculated.

[0389] The manufacturing specifications and evaluation results are shown in Table 6 below.

[0390] [Examples 27 to 29, Comparative Example 3]

[0391] Except having changed the enhancer into the compound and mass part described in Table 6, it carried out similarly to Example 26, and evaluated similarly.

[0392] [Table 6]

[0393]

[0394] <Results Summary>

[0395] The electrolytes, enhancers, electrolyte solutions of the present invention used in the embodiments, and the storage devices made using them show excellent solubility in organic solvents (non-aqueous solvents), charge and discharge efficiency, -10°C resistance value, cycle characteristics (volume change rate, capacity retention rate, resistance change rate), and a balance of high temperature characteristics.

[0396] In contrast, the comparative examples showed excellent solubility in organic solvents (non-aqueous solvents), charge and discharge efficiency, -10°C resistance value, cycle characteristics (volume change rate, capacity retention rate, resistance change rate), but were inferior in any of the high temperature characteristics.

Claims

1. An electrolyte for a power storage device, comprising a complex compound (A), characterized in that: The complex compound (A) comprises one or more of the complex compounds represented by the following formula (1): [Chemistry 1] In formula (1), X 1 is a P(═O) group or a P(═S) group, R 1 ~R 3 Each independently represents a group selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, a halogen atom, an alkoxy group, a silyloxy group, a thiosilyl group, and a group represented by the following formula (2), or a group selected from the group consisting of R 1 ~R 3 One of the two groups in the group is an oxygen atom and is bonded to the other to form a ring structure, R 1 ~R 3 At least one of them is a group containing a structure represented by the following formula (2); [Chemistry 2] Formula (2) represents an oligomer having a structure in which the repeating units shown in [ ] are linked, and the linking order of the repeating units is arbitrary. l indicates using [] l The number of repetitions of the enclosed repeating unit is 1 to 10. m represents [] m The number of repetitions of the enclosed repeating unit is a number from 0 to 10. n represents the use of [] n The number of repetitions of the enclosed repeating unit is a number from 0 to 10. M + is an alkali metal cation or a quaternary ammonium cation, Y 1 ~Y 3 are each independently an oxygen atom or a sulfur atom, B is a boron atom, G is a halogen atom, X 2 is a boron atom, a P(═O) group or a P(═S) group, Z represents that the preceding and succeeding groups are directly connected, or is a group selected from the group consisting of a substituted or unsubstituted alkylene group, an alkenylene group, a phenylene group, and an alkylene group having an ether group or a thioether group in the main chain, R 4 Each is independently a hydrogen atom, an alkyl group, an alkenyl group, a halogen atom, an alkoxy group, a siloxy group, or a thiosilyl group.

2. The electrolyte according to claim 1, characterized in that The complex compound has at least one boron halide group.

3. The electrolyte according to claim 1, characterized in that The complex compound has at least one of the siloxy group and / or the thiosilyl group.

4. The electrolyte according to claim 1, characterized in that The complex compound has: at least one boron halide group; and At least one of the siloxy group and / or the sulfosilyl group.

5. The electrolyte according to claim 1, characterized in that The complex compound comprises one or more selected from the group consisting of complex compounds represented by the following formulae (3) to (14), [Chemistry 3] [Chemistry 4] 6. A reinforcing agent for an electric storage device, characterized in that It contains the complex compound (A) according to any one of claims 1 to 5.

7. An electrolyte solution for an electricity storage device, comprising at least the complex compound (A) according to any one of claims 1 to 5 and an organic solvent, characterized in that: The concentration of the alkali metal cation or quaternary ammonium cation derived from the complex compound (A) in the entire electrolyte solution is 0.01 mol / L or more and 2.0 mol / L or less.

8. An electrolyte solution for an electricity storage device, comprising at least the complex compound (A) according to any one of claims 1 to 5 and an organic solvent, characterized in that: The concentration of the complex compound (A) in the entire electrolyte solution is 0.1 mass % or more and 30 mass % or less.

9. An electricity storage device produced using the electrolyte according to claim 7 or 8. 10 . An electricity storage device produced using the electrolyte according to claim 1 and / or the reinforcing agent according to claim 6 .

11. A solid-state electricity storage device produced using the electrolyte according to any one of claims 1 to 5 and / or the reinforcing agent according to claim 6.

12. A production method, which is a production method for synthesizing the complex compound (A) according to any one of claims 1 to 5, characterized in that: The complex compound (A) contains a P(═O) group or a P(═S) group, and / or a boron halide group, The production method comprises step 1: subjecting a boron halide salt (E) and a phosphorus compound (F) to a bonding reaction based on dehalogenation of a silyl group, The boron halide salt (E) is a salt composed of an anion having two or more halogen atoms bonded to boron, and an alkali metal cation or a quaternary ammonium cation. The phosphorus compound (F) is a compound having a siloxy group or a thiosilyl group bonded to a P(═O) group or a P(═S) group.

13. The manufacturing method according to claim 12, characterized in that: After the step 1, one or more steps 2 are further included: adding an additional reaction raw material consisting of a halogenated boron salt (E) and / or a phosphorus compound (F) to carry out a bonding reaction by dehalogenating a silyl group.

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