JP7439361B2 - Lithium salt complex compound, additive for lithium secondary batteries, and method for producing lithium salt complex compound - Google Patents

Description

The present disclosure relates to a lithium salt complex compound, an additive for lithium secondary batteries, and a method for producing a lithium salt complex compound.

Lithium salt compounds have traditionally been usefully used as reaction reagents, synthesis reaction catalysts, electrolytes for various electrochemical devices, doping agents, lubricating oil additives, and the like. Since many of these lithium salt compounds have poor thermal stability and stability against water, complex compounds with improved stability have been developed by treating lithium salt compounds with compounds that can be complexed. There is.

Specific examples of lithium salt complex compounds include lithium hexafluoroarsenate, complex compounds of lithium hexafluorophosphate and acetonitrile (see Patent Document 1), lithium halides, lithium tetrafluoroborate, and hexafluoroborate. Complexes of lithium salts such as lithium fluorophosphate and compounds such as N,N,N',N",N"-pentamethyldiethylenetriamine (see Patent Document 2), complexes of lithium hexafluorophosphate and crown ethers, etc. compound (see Patent Document 3), a complex compound of lithium hexafluoroarsenate or lithium hexafluorophosphate and 2-methyltetrahydrofuran (see Patent Document 4), a complex compound of lithium hexafluorophosphate and pyridine (Patent Document 5) ), a complex compound of lithium hexafluorophosphate and diethyl carbonate or ethylene carbonate (see Patent Document 6), a complex compound of lithium hexafluorophosphate and 1,4-dioxane (see Patent Document 7), etc. ing.

Special Publication No. 48-33733 Special Publication No. 53-31859 Japanese Patent Publication No. 59-151779 Special Publication No. 6-16421 Special table number 2002-514153 Patent No. 3555720 Patent No. 5862015

An object of the present disclosure is to provide a novel lithium salt complex compound and an additive for lithium secondary batteries containing this lithium salt complex compound.
Another object of the present disclosure is to provide a method for producing a lithium salt complex compound that can produce a lithium salt complex compound consisting of lithium tetrafluoroborate and lithium difluorophosphate.

Means for solving the above problems include the following aspects.
<1> Halogen atom, alkyl group optionally substituted with a halogen atom, alkoxy group optionally substituted with a halogen atom, alkenyl group optionally substituted with a halogen atom, even substituted with a halogen atom When the substituent L is at least one substituent selected from the group consisting of an alkynyl group, a cyclic ester group optionally substituted with a halogen atom or an alkyl group, an oxalato group, and an aryl group,
A lithium phosphate salt A1 having the substituent L directly bonded to a phosphorus atom, a lithium borate salt B1 having the substituent L directly bonding to a boron atom, and a sulfonic acid having the substituent L directly bonding to a sulfur atom. One type of lithium salt selected from the group consisting of lithium salt C1, a lithium sulfate salt having the substituent L directly bonded to a sulfur atom, and a sulfonylimidate lithium salt having the substituent L directly bonding to a sulfur atom. and,
A lithium phosphate salt A2 having a fluorine atom directly bonded to a phosphorus atom among the lithium phosphate salts A1; a lithium borate salt B2 having a fluorine atom directly bonding to a boron atom among the lithium borate salts B1; and one type of lithium-containing compound selected from the group consisting of sulfonic acid lithium salts C2 having a fluorine atom directly bonded to a sulfur atom among the sulfonic acid lithium salts C1;
A lithium salt complex compound consisting of (excluding combinations of the same compounds).

<2> Lithium difluorophosphate, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(oxalato)borate, lithium trifluoromethanesulfonate, lithium methylsulfate, lithium benzenesulfonate, lithium fluorosulfonate, lithium bis (trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, and lithium bis(perfluoroethylsulfonyl)imide;
one type of lithium-containing compound selected from the group consisting of lithium difluorophosphate, lithium hexafluorophosphate, lithium tetrafluoroborate, and lithium fluorosulfonate;
The lithium salt complex compound according to <1> consisting of

<3> One type of lithium salt selected from the group consisting of lithium difluorophosphate, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(oxalato)borate, lithium fluorosulfonate, and lithium methyl sulfate; ,
one type of lithium-containing compound selected from the group consisting of lithium difluorophosphate, lithium hexafluorophosphate, lithium tetrafluoroborate, and lithium fluorosulfonate;
The lithium salt complex compound according to <1> or <2> consisting of

<4> A complex compound consisting of lithium hexafluorophosphate and lithium difluorophosphate,
A complex compound consisting of lithium tetrafluoroborate and lithium difluorophosphate,
A complex compound consisting of lithium bis(oxalato)borate and lithium difluorophosphate,
A complex compound consisting of lithium methyl sulfate and lithium difluorophosphate,
A complex compound consisting of lithium tetrafluoroborate and lithium hexafluorophosphate,
A complex compound consisting of lithium bis(oxalato)borate and lithium hexafluorophosphate,
A complex compound consisting of lithium methyl sulfate and lithium hexafluorophosphate,
A complex compound consisting of lithium fluorosulfate and lithium difluorophosphate, or
The lithium salt complex compound according to any one of <1> to <3>, which is a complex compound consisting of lithium fluorosulfate and lithium hexafluorophosphate.

<5> An additive for lithium secondary batteries, comprising the lithium salt complex compound according to any one of <1> to <4>.

<6> A method for producing a lithium salt complex compound consisting of lithium tetrafluoroborate and lithium difluorophosphate, comprising:
A method for producing a lithium salt complex compound, comprising the step of obtaining a solution of the lithium salt complex compound by reacting boron oxide, lithium hexafluorophosphate, and lithium fluoride in an organic solvent.
<7> The method for producing a lithium salt complex compound according to <6>, wherein the reaction temperature in the reaction of the boron oxide, the lithium hexafluorophosphate, and the lithium fluoride is 20° C. or higher.
<8> The step of obtaining a solution of the lithium salt complex compound includes:
obtaining a mixture of a solution of the lithium salt complex compound and a solid precipitate by reacting boron oxide, lithium hexafluorophosphate, and lithium fluoride in an organic solvent;
removing the solid precipitate from the mixture;
The method for producing a lithium salt complex compound according to <6> or <7>, comprising:
<9> The method for producing a lithium salt complex compound according to any one of <6> to <8>, further comprising a step of taking out the lithium salt complex compound from the solution of the lithium salt complex compound.
<10> The organic solvent is acetone, methyl ethyl ketone, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, acetonitrile, propionitrile, dimethoxyethane, diethylene glycol dimethyl ether, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate. The method for producing a lithium salt complex compound according to any one of <6> to <9>, which is at least one selected from the group consisting of , ethylene carbonate, propylene carbonate, and fluoroethylene carbonate.

According to the present disclosure, a novel lithium salt complex compound and an additive for lithium secondary batteries containing this lithium salt complex compound are provided.
Further, according to the present disclosure, there is provided a method for producing a lithium salt complex compound that can produce a lithium salt complex compound consisting of lithium tetrafluoroborate and lithium difluorophosphate.

In this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as lower and upper limits.
In this specification, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, the amount of each component in the composition refers to the total amount of the multiple substances present in the composition. means.
In this specification, the term "process" is used not only to refer to an independent process, but also to include any process that is not clearly distinguishable from other processes as long as the intended purpose of the process is achieved. It will be done.

[Lithium salt complex compound]
The lithium salt complex compound of the present disclosure is
Halogen atom, alkyl group optionally substituted with halogen atom, alkoxy group optionally substituted with halogen atom, alkenyl group optionally substituted with halogen atom, alkynyl group optionally substituted with halogen atom , when the substituent L is at least one substituent selected from the group consisting of a cyclic ester group optionally substituted with a halogen atom or an alkyl group, an oxalato group, and an aryl group,
A lithium phosphate salt A1 having the substituent L directly bonded to a phosphorus atom, a lithium borate salt B1 having the substituent L directly bonding to a boron atom, and a sulfonic acid having the substituent L directly bonding to a sulfur atom. One type of lithium salt selected from the group consisting of lithium salt C1, a lithium sulfate salt having the substituent L directly bonded to a sulfur atom, and a sulfonylimidate lithium salt having the substituent L directly bonding to a sulfur atom. (hereinafter also referred to as "specific lithium salt"),
A lithium phosphate salt A2 having a fluorine atom directly bonded to a phosphorus atom among the lithium phosphate salts A1; a lithium borate salt B2 having a fluorine atom directly bonding to a boron atom among the lithium borate salts B1; and one type of lithium-containing compound (hereinafter also referred to as "specific compound") selected from the group consisting of sulfonate lithium salt C2 having a fluorine atom directly bonded to a sulfur atom among the sulfonate lithium salts C1; ,
It is a lithium salt complex compound consisting of
However, combinations of the same compounds are excluded.
For example, combinations of lithium difluorophosphates, combinations of lithium hexafluorophosphates, combinations of lithium tetrafluoroborates, combinations of lithium fluorosulfonates, etc. are not included in the lithium salt complex compounds of the present disclosure. .

The lithium salt complex compound of the present disclosure is a novel lithium salt complex compound consisting of a specific lithium salt and a specific compound.

The lithium salt complex compound of the present disclosure exhibits endothermic dissociation behavior at a temperature that is not observed in the raw material compounds (specific lithium salt and specific compound).
That is, the lithium salt complex compound of the present disclosure is a compound with excellent thermal stability.

Next, the specific lithium salt and specific compound that form the lithium salt complex compound of the present disclosure will be explained in order.

<Specified lithium salt>
The specific lithium salts include a lithium phosphate salt A1 having the substituent L directly bonded to a phosphorus atom, a lithium borate salt B1 having the substituent L directly bonding to a boron atom, and a lithium borate salt B1 having the substituent L directly bonding to a sulfur atom. selected from the group consisting of sulfonic acid lithium salt C1 having L, sulfuric acid lithium salt having said substituent L directly bonded to a sulfur atom, and sulfonylimidate lithium salt having said substituent L directly bonding to a sulfur atom. It is one type.

The substituent L is a halogen atom, an alkyl group optionally substituted with a halogen atom, an alkoxy group optionally substituted with a halogen atom, an alkenyl group optionally substituted with a halogen atom, or an alkyl group optionally substituted with a halogen atom. The substituent is one type of substituent selected from the group consisting of an alkynyl group which may be substituted with a halogen atom or an alkyl group, a cyclic ester group which may be substituted with a halogen atom or an alkyl group, an oxalato group, and an aryl group.
The substituent L may be one type or two or more types. When there are two or more types of substituents L, they may be the same or different.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
As the halogen atom, a fluorine atom is preferred.

The alkyl group optionally substituted with a halogen atom means an unsubstituted alkyl group or a halogenated alkyl group.
A halogenated alkyl group means an alkyl group substituted with at least one halogen atom.
The unsubstituted alkyl group and the halogenated alkyl group may each be linear, branched, or cyclic.
Examples of the unsubstituted alkyl group include unsubstituted alkyl groups having 1 to 12 carbon atoms, and specifically, methyl group, ethyl group, n-propyl group, isopropyl group, 1-ethylpropyl group, n -butyl group, isobutyl group, sec-butyl group, tert-butyl group, 2-methylbutyl group, 3,3-dimethylbutyl group, n-pentyl group, isopentyl group, neopentyl group, 1-methylpentyl group, n-hexyl group, isohexyl group, sec-hexyl group, tert-hexyl group, n-heptyl group, isoheptyl group, sec-heptyl group, tert-heptyl group, n-octyl group, isooctyl group, sec-octyl group, tert-octyl group , nonyl group, decyl group, undecyl group, dodecyl group, etc.
The unsubstituted alkyl group is preferably a methyl group, an ethyl group, an n-propyl group, or an isopropyl group, and more preferably a methyl group or an ethyl group.
Examples of the halogenated alkyl group include halogenated alkyl groups having 1 to 6 carbon atoms, and specifically, fluoromethyl group, difluoromethyl group, trifluoromethyl group, 2,2,2-trifluoroethyl group. , perfluoroethyl group, perfluoropropyl group, perfluorobutyl group, perfluoropentyl group, perfluorohexyl group, perfluoroisopropyl group, perfluoroisobutyl group, chloromethyl group, chloroethyl group, chloropropyl group, bromomethyl group, Examples include bromoethyl group, bromopropyl group, methyl iodide group, ethyl iodide group, and propyl iodide group.
The halogenated alkyl group is preferably a fluoroalkyl group having 1 to 6 carbon atoms, such as a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a perfluoroethyl group, or a perfluoroethyl group. A propyl group, perfluorobutyl group, or perfluorohexyl group is more preferred.

The alkoxy group optionally substituted with a halogen atom means an unsubstituted alkoxy group or a halogenated alkoxy group.
A halogenated alkoxy group means an alkoxy group substituted with at least one halogen atom.
The unsubstituted alkoxy group and the halogenated alkoxy group may each be linear, branched, or cyclic.
Examples of the unsubstituted alkoxy group include unsubstituted alkoxy groups having 1 to 6 carbon atoms, and specifically, methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, sec- Examples include butoxy group, tert-butoxy group, pentyloxy group, 2-methylbutoxy group, 1-methylpentyloxy group, neopentyloxy group, 1-ethylpropoxy group, hexyloxy group, 3,3-dimethylbutoxy group, etc. It will be done.
The unsubstituted alkoxy group is preferably an ethoxy group or a methoxy group, and more preferably a methoxy group.
Examples of the halogenated alkoxy group include a group having a structure in which the aforementioned unsubstituted alkoxy group having 1 to 6 carbon atoms is substituted with at least one halogen atom.

The alkenyl group optionally substituted with a halogen atom means an unsubstituted alkenyl group or a halogenated alkenyl group.
A halogenated alkenyl group means an alkenyl group substituted with at least one halogen atom.
The unsubstituted alkenyl group and the halogenated alkenyl group may each be linear, branched, or cyclic.
Examples of unsubstituted alkenyl groups include unsubstituted alkenyl groups having 2 to 6 carbon atoms, and specifically, vinyl groups, 1-propenyl groups, allyl groups (2-propenyl groups), isopropenyl groups, 1-butenyl group, 2-butenyl group, 3-butenyl group, pentenyl group, hexenyl group, 2-methyl-2-propenyl group, 1-methyl-2-propenyl group, 2-methyl-1-propenyl group, hexenyl group Examples include.
The unsubstituted alkenyl group is preferably a vinyl group or an allyl group, and more preferably a vinyl group.
Examples of the halogenated alkenyl group include a group having a structure in which an unsubstituted alkenyl group having 2 to 6 carbon atoms is substituted with at least one halogen atom.

The alkynyl group optionally substituted with a halogen atom means an unsubstituted alkynyl group or a halogenated alkynyl group.
A halogenated alkynyl group means an alkynyl group substituted with at least one halogen atom.
The unsubstituted alkynyl group and the halogenated alkynyl group may each be linear, branched, or cyclic.
Examples of the unsubstituted alkynyl group include unsubstituted alkynyl groups having 2 to 6 carbon atoms, and specifically, ethynyl group, 1-propynyl group, 2-propynyl group (synonymous with propargyl group), 1- Butynyl group, 2-butynyl group, 3-butynyl group, 1-pentynyl group, 2-pentynyl group, 3-pentynyl group, 4-pentynyl group, 5-hexynyl group, 1-methyl-2-propynyl group, 2-methyl -3-butynyl group, 2-methyl-3-pentynyl group, 1-methyl-2-butynyl group, 1,1-dimethyl-2-propynyl group, 1,1-dimethyl-2-butynyl group, 1-hexynyl group, etc. can be mentioned.
Examples of the halogenated alkynyl group include a group having a structure in which the aforementioned unsubstituted alkynyl group having 2 to 6 carbon atoms is substituted with at least one halogen atom.

Examples of the cyclic ester group which may be substituted with a halogen atom or an alkyl group include a group having a structure in which a cyclic ester group is substituted with at least one halogen atom or an alkyl group.
Examples of the cyclic ester group include a group in which one hydrogen atom is dissociated from a lactone. Examples of the lactone include α-acetolactone, β-propiolactone, γ-butyrolactone, and δ-valerolactone.
The halogen atom has the same meaning as the halogen atom described above.
Examples of the alkyl group include those similar to the above-mentioned unsubstituted alkyl group having 1 to 6 carbon atoms.

Examples of the oxalato group include a group represented by the following formula (a). * represents the bonding position.

The "aryl group" in the present disclosure includes both an unsubstituted aryl group and a substituted aryl group.
Examples of the aryl group include an unsubstituted aryl group having 6 to 20 carbon atoms and a substituted aryl group having 7 to 20 carbon atoms. Specifically, phenyl group; an alkylbenzene with one hydrogen atom removed; (eg, benzyl group, tolyl group, xylyl group, methiyl group, etc.); naphthyl group; group in which one hydrogen atom is removed from the alkyl group of naphthalene; and the like. Note that the substituents in the substituted aryl group are not limited to the above, and include, for example, the aforementioned halogen atom, halogenated alkyl group, unsubstituted alkoxy group, halogenated alkoxy group, unsubstituted alkenyl group, and halogenated alkenyl group. group, unsubstituted alkynyl group, halogenated alkynyl group, and the like.
As the aryl group, a phenyl group is preferred.

The substituent L directly bonded to the phosphorus atom of the lithium phosphate salt is a fluorine atom, a methoxy group, an ethoxy group, an isopropoxy group, a 2,2,2-trifluoroethoxy group, a pentafluoroethoxy group, a phenoxy group, or an oxalato group. The group is preferable,
The substituent L directly bonded to the boron atom of the lithium borate salt is preferably a fluorine atom or an oxalato group,
The substituent L directly bonded to the sulfur atom of the sulfonic acid lithium salt is preferably a fluorine atom, a methyl group, a trifluoromethyl group, a vinyl group, an allyl group, or a phenyl group,
The substituent L directly bonded to the sulfur atom of the lithium sulfate salt is preferably a methyl group or a dodecyl group,
The substituent L directly bonded to the sulfur atom of the sulfonylimidate lithium salt is preferably a fluorine atom, a trifluoromethyl group, or a pentafluoroethyl group.

(Lithium phosphate salt)
The lithium salt complex compound of the present disclosure can be formed from a lithium phosphate salt having a substituent L directly bonded to a phosphorus atom (hereinafter also simply referred to as "lithium phosphate salt") and a specific compound.
Examples of lithium phosphate salts include lithium hexafluorophosphate, lithium difluorophosphate, dimethyllithium phosphate, diethyllithium phosphate, diisopropyllithium phosphate, and bis(2,2,2-trifluoroethyl)lithium phosphate. , bis(pentafluoroethyl)lithium phosphate, diphenyllithium phosphate, lithium tetrafluorooxalatophosphate, difluorobis(oxalato)lithium phosphate, tris(oxalato)lithium phosphate, and the like.
As the lithium phosphate salt, lithium difluorophosphate or lithium hexafluorophosphate is preferred.

(Lithium borate salt)
The lithium salt complex compound of the present disclosure can be formed from a lithium borate salt having a substituent L directly bonded to a boron atom (hereinafter also simply referred to as "lithium borate salt") and a specific compound.
Examples of the lithium borate salt include lithium tetrafluoroborate, lithium difluorooxalatoborate, and lithium bis(oxalato)borate.
As the lithium borate salt, lithium tetrafluoroborate or lithium bis(oxalato)borate is preferable, and lithium bis(oxalato)borate is more preferable.

(Sulfonic acid lithium salt)
The lithium salt complex compound of the present disclosure can be formed from a sulfonic acid lithium salt having a substituent L directly bonded to a sulfur atom (hereinafter also simply referred to as "sulfonic acid lithium salt") and a specific compound.
Examples of the lithium sulfonate salt include lithium fluorosulfonate, lithium methanesulfonate, lithium trifluoromethanesulfonate, lithium vinylsulfonate, lithium allylsulfonate, and lithium benzenesulfonate.
As the lithium sulfonate salt, lithium fluorosulfonate, lithium trifluoromethanesulfonate, or lithium benzenesulfonate is preferable.

(Lithium sulfate salt)
The lithium salt complex compound of the present disclosure can be formed from a lithium sulfate salt having a substituent L directly bonded to a sulfur atom (hereinafter also simply referred to as "lithium sulfate salt") and a specific compound.
Examples of lithium sulfate salts include lithium methyl sulfate and lithium dodecyl sulfate.
As the lithium sulfate salt, lithium methyl sulfate is preferred.

(Sulfonylimidic acid lithium salt)
The lithium salt complex compound of the present disclosure can be formed from a sulfonylimidate lithium salt having a substituent L directly bonded to a sulfur atom (hereinafter also simply referred to as "sulfonylimide acid lithium salt") and a specific compound.
The sulfonylimidate lithium salt is not particularly limited, but lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, or lithium bis(perfluoroethylsulfonyl)imide is preferred.

<Specific compound>
Among the lithium phosphate salts A1, the specific compounds include lithium phosphate salts A2 having a fluorine atom directly bonded to a phosphorus atom (hereinafter also referred to as "fluorine-containing lithium phosphate salts A2"), and among lithium borate salts B1. , a lithium borate salt B2 having a fluorine atom directly bonded to a boron atom (hereinafter also referred to as "fluorine-containing lithium borate B2"), and a lithium sulfonate salt C1, in which a fluorine atom directly bonded to a sulfur atom is It is one type of lithium-containing compound selected from the group consisting of sulfonic acid lithium salt C2 (hereinafter also referred to as "fluorine-containing sulfonic acid lithium salt C2").

(Fluorine-containing lithium phosphate salt A2)
The lithium salt complex compound of the present disclosure can be formed from a specific lithium salt and a fluorine-containing lithium phosphate salt A2.
Examples of the fluorine-containing lithium phosphate salt A2 include lithium hexafluorophosphate, lithium difluorophosphate, lithium tetrafluorooxalatophosphate, and lithium difluorobis(oxalato)phosphate.
As the fluorine-containing lithium phosphate salt A2, lithium difluorophosphate or lithium hexafluorophosphate is preferable.

(Fluorine-containing lithium borate salt B2)
The lithium salt complex compound of the present disclosure may be formed from a specific lithium salt and a fluorine-containing lithium borate salt B2.
Examples of the fluorine-containing lithium borate salt B2 include lithium tetrafluoroborate, lithium difluoroxalatoborate, and the like.
As the fluorine-containing lithium borate salt B2, lithium tetrafluoroborate is preferable.

(Fluorine-containing sulfonic acid lithium salt C2)
The lithium salt complex compound of the present disclosure can be formed from a specific lithium salt and a fluorine-containing lithium sulfonate salt C2.
Examples of the fluorine-containing lithium sulfonate salt C2 include lithium fluorosulfonate, which is preferably used.

[Preferred embodiment of lithium salt complex compound]
Preferred embodiments of the lithium salt complex compound of the present disclosure include lithium difluorophosphate, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(oxalato)borate, lithium trifluoromethanesulfonate, lithium methylsulfate, and benzenesulfonic acid. One type of lithium salt (specific lithium salt) selected from the group consisting of lithium, lithium fluorosulfonate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, and lithium bis(perfluoroethylsulfonyl)imide )and,
One type of lithium-containing compound (specific compound) selected from the group consisting of lithium difluorophosphate, lithium hexafluorophosphate, lithium tetrafluoroborate, and lithium fluorosulfonate;
It is a complex compound consisting of

That is, preferred embodiments of the lithium salt complex compounds of the present disclosure are Complex Compounds 1 to 27 below.
・Complex compound 1
A complex compound consisting of lithium hexafluorophosphate and lithium difluorophosphate.
・Complex compound 2
A complex compound consisting of lithium tetrafluoroborate and lithium difluorophosphate.
・Complex compound 3
A complex compound consisting of lithium bis(oxalato)borate and lithium difluorophosphate.
・Complex compound 4
A complex compound consisting of lithium trifluoromethanesulfonate and lithium difluorophosphate.
・Complex compound 5
A complex compound consisting of lithium methyl sulfate and lithium difluorophosphate.
・Complex compound 6
A complex compound consisting of lithium benzenesulfonate and lithium difluorophosphate.
・Complex compound 7
A complex compound consisting of lithium bis(trifluoromethanesulfonyl)imide and lithium difluorophosphate.
・Complex compound 8
A complex compound consisting of lithium bis(fluorosulfonyl)imide and lithium difluorophosphate.
・Complex compound 9
A complex compound consisting of lithium bis(perfluoroethylsulfonyl)imide and lithium difluorophosphate.

・Complex compound 10
A complex compound consisting of lithium tetrafluoroborate and lithium hexafluorophosphate.
・Complex compound 11
A complex compound consisting of lithium bis(oxalato)borate and lithium hexafluorophosphate.
・Complex compound 12
A complex compound consisting of lithium trifluoromethanesulfonate and lithium hexafluorophosphate.
・Complex compound 13
A complex compound consisting of lithium methyl sulfate and lithium hexafluorophosphate.
・Complex compound 14
A complex compound consisting of lithium benzenesulfonate and lithium hexafluorophosphate.
・Complex compound 15
A complex compound consisting of lithium bis(trifluoromethanesulfonyl)imide and lithium hexafluorophosphate.
・Complex compound 16
A complex compound consisting of lithium bis(fluorosulfonyl)imide and lithium hexafluorophosphate.
・Complex compound 17
A complex compound consisting of lithium bis(perfluoroethylsulfonyl)imide and lithium hexafluorophosphate.

・Complex compound 18
A complex compound consisting of lithium bis(oxalato)borate and lithium tetrafluoroborate.
・Complex compound 19
A complex compound consisting of lithium trifluoromethanesulfonate and lithium tetrafluoroborate.
・Complex compound 20
A complex compound consisting of lithium methyl sulfate and lithium tetrafluoroborate.
・Complex compound 21
A complex compound consisting of lithium benzenesulfonate and lithium tetrafluoroborate.
・Complex compound 22
A complex compound consisting of lithium bis(trifluoromethanesulfonyl)imide and lithium tetrafluoroborate.
・Complex compound 23
A complex compound consisting of lithium bis(fluorosulfonyl)imide and lithium tetrafluoroborate.
・Complex compound 24
A complex compound consisting of lithium bis(perfluoroethylsulfonyl)imide and lithium tetrafluoroborate.
・Complex compound 25
A complex compound consisting of lithium fluorosulfonate and lithium difluorophosphate.
・Complex compound 26
A complex compound consisting of lithium fluorosulfonate and lithium hexafluorophosphate.
・Complex compound 27
A complex compound consisting of lithium fluorosulfonate and lithium tetrafluoroborate.

Complex compounds 1 to 27 are specifically shown below. Note that the numbers (1) to (27) shown below correspond to the above complex compounds 1 to 27, respectively.
Note that the lithium salt complex compound of the present disclosure is not limited to the following complex compound and its structure.

A more preferred embodiment of the lithium salt complex compound of the present disclosure is a group consisting of lithium difluorophosphate, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(oxalato)borate, lithium fluorosulfonate, and lithium methyl sulfate. One type of lithium salt (specific lithium salt) selected from;
One type of lithium-containing compound (specific compound) selected from the group consisting of lithium difluorophosphate, lithium hexafluorophosphate, lithium tetrafluoroborate, and lithium fluorosulfonate;
It is a complex compound consisting of

That is, more preferred embodiments of the lithium salt complex compound of the present disclosure are the following complex compounds among the above-mentioned complex compounds 1 to 27.
・Complex compound 1
A complex compound consisting of lithium hexafluorophosphate and lithium difluorophosphate.
・Complex compound 2
A complex compound consisting of lithium tetrafluoroborate and lithium difluorophosphate.
・Complex compound 3
A complex compound consisting of lithium bis(oxalato)borate and lithium difluorophosphate.
・Complex compound 5
A complex compound consisting of lithium methyl sulfate and lithium difluorophosphate.

・Complex compound 10
A complex compound consisting of lithium tetrafluoroborate and lithium hexafluorophosphate.
・Complex compound 11
A complex compound consisting of lithium bis(oxalato)borate and lithium hexafluorophosphate.
・Complex compound 13
A complex compound consisting of lithium methyl sulfate and lithium hexafluorophosphate.

・Complex compound 18
A complex compound consisting of lithium bis(oxalato)borate and lithium tetrafluoroborate.
・Complex compound 20
A complex compound consisting of lithium methyl sulfate and lithium tetrafluoroborate.
・Complex compound 25
A complex compound consisting of lithium fluorosulfonate and lithium difluorophosphate.
・Complex compound 26
A complex compound consisting of lithium fluorosulfonate and lithium hexafluorophosphate.
・Complex compound 27
A complex compound consisting of lithium fluorosulfonate and lithium tetrafluoroborate.

More preferred embodiments of the lithium salt complex compound of the present disclosure are the following complex compounds among the above-mentioned complex compounds 1 to 27.
・Complex compound 1
A complex compound consisting of lithium hexafluorophosphate and lithium difluorophosphate.
・Complex compound 2
A complex compound consisting of lithium tetrafluoroborate and lithium difluorophosphate.
・Complex compound 3
A complex compound consisting of lithium bis(oxalato)borate and lithium difluorophosphate.
・Complex compound 5
A complex compound consisting of lithium methyl sulfate and lithium difluorophosphate.
・Complex compound 10
A complex compound consisting of lithium tetrafluoroborate and lithium hexafluorophosphate.
・Complex compound 11
A complex compound consisting of lithium bis(oxalato)borate and lithium hexafluorophosphate.
・Complex compound 13
A complex compound consisting of lithium methyl sulfate and lithium hexafluorophosphate.
・Complex compound 25
A complex compound consisting of lithium fluorosulfonate and lithium difluorophosphate.
・Complex compound 26
A complex compound consisting of lithium fluorosulfonate and lithium hexafluorophosphate.

[Method for producing lithium salt complex compound]
In the method for producing the lithium salt complex compound of the present disclosure, conventionally known methods for obtaining complex compounds can generally be applied. The lithium salt complex compound of the present disclosure can usually be obtained by mixing a specific lithium salt and a specific compound, but if it is possible to obtain a lithium salt complex compound as a homogeneous product, the mixing Methods and conditions can be selected arbitrarily.

When mixing the specific lithium salt and the specific compound, the mixing molar ratio of the specific compound to the specific lithium salt (specific compound/specific lithium salt) should be 1 to 6 from the viewpoint of stably forming a lithium salt complex compound. The number is preferably 1 to 4, more preferably 1 to 4.
When the mixing molar ratio is 1 or more, it is easy to avoid a situation where the specific lithium salt becomes excessive.
When the mixing molar ratio is 6 or less, it is easy to avoid a situation in which the specific compound becomes excessive.

Although the method of mixing the specific lithium salt and the specific compound is not particularly limited, it is preferable to mix the two using an organic solvent.
However, in order to obtain a homogeneous product (lithium salt complex compound), it is preferable to use an organic solvent that can dissolve at least one of the raw material compounds (specific lithium salt and specific compound).

Any organic solvent can be used as long as it does not inhibit the formation of the desired lithium salt complex compound.
As the organic solvent, a single solvent consisting of one type of compound may be used, or a mixed solvent consisting of two or more types of compounds may be used.
Examples of organic solvents include acetone, ethyl acetate, acetonitrile, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, hexane, heptane, octane, nonane, decane, toluene, xylene, ethylbenzene, propylbenzene, butylbenzene, pentylbenzene, hexyl. At least one selected from the group consisting of benzene, heptylbenzene, cyclohexylbenzene, tetralin, mesitylene, methylcyclopentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, and cyclononane.
In each of these compounds, when isomers exist, the concept of each compound includes all isomers.
For example, the concept of xylene includes ortho-xylene, meta-xylene, and para-xylene, and the concept of propylbenzene includes normal propylbenzene and isopropylbenzene (also known as cumene).

The specific lithium salt and the specific compound can be mixed under either normal pressure or reduced pressure, but in order to prevent the mixing of components (e.g. moisture) that inhibit the formation of the lithium salt complex compound, the reaction system must be heated with nitrogen, argon, etc. It is preferable to carry out the process under an inert atmosphere.

The temperature at which the specific lithium salt and the specific compound are mixed is preferably 20°C to 200°C, more preferably 20°C to 150°C, and even more preferably 20°C to 100°C.
When the temperature is 20°C or higher, the generation of a lithium salt complex compound is likely to be promoted, and when the temperature is 200°C or lower, dissociation of the generated lithium salt complex compound is suppressed and the production rate is likely to be improved.

The mixing time of the specific lithium salt and the specific compound is preferably 30 minutes to 12 hours, more preferably 1 hour to 8 hours, from the viewpoint of efficiently proceeding the reaction.

After mixing the specific lithium salt and the specific compound, there is no particular restriction on the method for taking out the lithium salt complex compound of the present disclosure, and any conventionally known method can be selected and carried out. For example, if the lithium salt complex compound is obtained as a solid containing only the desired components, it can be taken out without any special treatment, or if it is obtained as a solid in the form of a slurry dispersed in a solvent, The solvent can also be removed by separation and drying.
For example, if the lithium salt complex compound is obtained in a state dissolved in a solvent, the solution may be concentrated by heating to distill off the solvent, or a solvent in which the generated lithium salt complex compound does not dissolve may be removed from the solution. It is also possible to perform a method in which the solvent is precipitated in addition to the above, and the solvent is removed by separation and drying.

As a method for drying the extracted lithium salt complex compound, any conventionally known method can be selected and carried out. For example, a static drying method using a tray dryer; a fluidized drying method using a conical dryer; a method of drying using a device such as a hot plate or an oven; a method of supplying warm air or hot air with a dryer such as a dryer. method; etc.

The pressure for drying the extracted lithium salt complex compound can be either normal pressure or reduced pressure, but the temperature for drying is preferably 20°C to 200°C, and preferably 20°C to 150°C. The temperature is more preferably 20°C to 100°C. When the temperature is 20° C. or higher, the drying efficiency is good, and when the temperature is 200° C. or lower, the dissociation of the generated lithium salt complex compound is suppressed, and the lithium salt complex compound can be easily taken out stably.

The extracted lithium salt complex compound may be used as it is, for example, may be used after being dispersed or dissolved in a solvent, or may be used after being mixed with other solid substances.

The lithium salt complex compound of the present disclosure can be usefully used as an additive for lithium batteries, a reaction reagent, a synthesis reaction catalyst, an electrolyte for various electrochemical devices, a doping agent, an additive for lubricating oil, and the like.
The lithium salt complex compound is preferably used as an additive for lithium batteries, particularly as an additive for lithium secondary batteries.

[Additive for lithium secondary batteries]
The secondary battery additive of the present disclosure includes the lithium salt complex compound described above.
The additive for secondary batteries of the present disclosure is particularly suitable as an additive for non-aqueous electrolytes of lithium secondary batteries.

[Another embodiment of the method for producing a lithium salt complex compound (Production method A)]
Next, another embodiment of the method for manufacturing a lithium salt complex compound of the present disclosure (hereinafter also referred to as "manufacturing method A") will be described.
Production method A is a method for producing a lithium salt complex compound (i.e., the above-mentioned complex compound 2; the structure is as follows) consisting of lithium tetrafluoroborate and lithium difluorophosphate, in which boron oxide and hexafluorophosphate The method includes a step of obtaining a solution of the lithium salt complex compound (complex compound 2) by reacting lithium and lithium fluoride in an organic solvent (hereinafter also referred to as "solution manufacturing step").

Manufacturing method A is a manufacturing method that is different from the method for manufacturing a lithium salt complex compound described above.
Production method A uses lithium tetrafluoroborate itself and lithium difluorophosphate itself, which constitute complex compound 2, as raw materials for a lithium salt complex compound (complex compound 2) consisting of lithium tetrafluoroborate and lithium difluorophosphate. This is a production method that uses boron oxide, lithium hexafluorophosphate, and lithium fluoride instead of using lithium fluoride.
Complex compound 2 can be manufactured by this manufacturing method A, and as described above, it can also be manufactured by a method using lithium tetrafluoroborate itself and lithium difluorophosphate itself.

In _the solution manufacturing step in manufacturing method _A , a lithium salt _complex compound ( A solution of complex compound 2) is obtained.
The reaction scheme of the reaction in the solution production process is considered to be as follows.

As mentioned above, due to the reaction in the solution manufacturing process,
Production _of lithium tetrafluoroborate ( _LiBF4 ) and lithium difluorophosphate ( _LiPO2F2 ),
Formation of complex compound 2 by the generated lithium tetrafluoroborate (LiBF ₄ ) and lithium difluorophosphate (LiPO ₂ F ₂ ), and
Dissolution of the formed complex compound 2 into the organic solvent takes place.
In the reaction in the solution production process, a solution of complex compound 2 is thus produced.
Further, a part of the generated lithium difluorophosphate (LiPO ₂ F ₂ ) is precipitated in the reaction solution (ie, the solution of complex compound 2) after the above reaction, and is precipitated and removed from the reaction solution.

Production method A, as described above, produces a lithium salt complex compound (complex compound 2) consisting of lithium tetrafluoroborate and lithium difluorophosphate while synthesizing each of lithium tetrafluoroborate and lithium difluorophosphate. Therefore, the productivity of complex compound 2 is excellent.

In the above reaction scheme, the molar ratio of LiBF ₄ to LiPO ₂ F ₂ in complex compound 2 [LiBF ₄ /LiPO ₂ F ₂ ] is omitted.
The molar ratio [LiBF ₄ /LiPO ₂ F ₂ ] in complex compound 2 is preferably 1 to 4, more preferably 1 to 3, from the viewpoint of stability in organic solvents and solubility in organic solvents. be.
Further, a part of lithium difluorophosphate (LiPO ₂ F ₂ ) is precipitated in the reaction solution (ie, the solution of complex compound 2) after the above reaction, and is precipitated and removed from the reaction solution.

In the solution manufacturing process, the amount of lithium hexafluorophosphate (LiPF ₆ ) used is preferably 100 mol % to 200 mol %, more preferably 120 mol %, based on the amount of boron oxide (B ₂ O ₃ ) used. % to 180 mol%, more preferably 140 mol% to 160 mol%, and ideally 150 mol%.
In the solution production process, the amount of lithium fluoride (LiF) used is preferably 150 mol% to 250 mol%, more preferably 170 mol% to 230 mol%, based on the amount of boron oxide (B ₂ O ₃ ) used. It is mol%, more preferably 190 mol% to 210 mol%, ideally 200 mol%.

In the solution production process, the reaction between boron oxide, lithium hexafluorophosphate, and lithium fluoride is performed in the presence of an organic solvent.
There is no particular limitation on the specific embodiment in which the above reaction is carried out in the presence of an organic solvent.
As a specific aspect, for example,
An embodiment in which boron oxide and lithium fluoride are added to a solution of lithium hexafluorophosphate dissolved in an organic solvent (hereinafter referred to as "Aspect 1");
An embodiment in which lithium hexafluorophosphate is added to a dispersion (e.g., slurry) in which powders of boron oxide and lithium fluoride are dispersed in an organic solvent (hereinafter referred to as "Embodiment 2");
etc.

The type of organic solvent used in Production Method A is not particularly limited.
As the organic solvent in production method A, a single solvent consisting of one type of compound may be used, or a mixed solvent consisting of two or more types of compounds may be used.
As the organic solvent in production method A, from the viewpoint of dissolving the lithium salt complex compound more stably and at a higher concentration,
Acetone, methyl ethyl ketone, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, acetonitrile, propionitrile, dimethoxyethane, diethylene glycol dimethyl ether, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, and Preferably, it is at least one selected from the group consisting of fluoroethylene carbonate.

The organic solvent in Production Method A is selected from the viewpoint of dissolving the lithium salt complex compound more stably and at a higher concentration.
At least one selected from the group consisting of ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, dimethoxyethane, diethylene glycol dimethyl ether, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, and fluoroethylene carbonate It is more preferable to include one type,
It is more preferable to contain at least one member selected from the group consisting of dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, and fluoroethylene carbonate.

When the organic solvent in Production Method A contains at least one selected from the group consisting of dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, and fluoroethylene carbonate, dimethyl carbonate accounts for the total amount of the organic solvent. The total ratio of , ethyl methyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, and fluoroethylene carbonate is preferably 60% by mass or more, more preferably 80% by mass or more.

The amount of organic solvent used in the solution manufacturing process is preferably 50% to 97% by mass, more preferably 65% by mass, based on the total amount of organic solvent, boron oxide, lithium hexafluorophosphate, and lithium fluoride. The amount is preferably from 75% to 93% by weight, more preferably from 75% to 93% by weight.
When the amount of the organic solvent used is 50% by mass or more, complex compound 2 can be more stably dissolved in the solution produced.
When the amount of organic solvent used is 97% by mass or less, the amount of raw materials can be secured to a certain extent, and as a result, the amount of complex compound 2 to be produced can also be easily secured, which is advantageous in terms of practicality. .

The concentration of complex compound 2 in the solution produced is preferably 3% by mass to 50% by mass, more preferably 5% by mass to 35% by mass, and even more preferably 7% by mass to 25% by mass. .
When the concentration of the complex compound 2 is 3% by mass or more, it has excellent practicality for various uses (specific examples of uses will be described later).
When the concentration of complex compound 2 is 50% by mass or less, the solution of complex compound 2 has excellent storage stability.

The above reaction can be carried out under normal pressure or reduced pressure.
The above reaction is preferably carried out under an inert atmosphere (for example, under a nitrogen atmosphere, under an argon atmosphere, etc.) from the viewpoint of preventing contamination of components (for example, water) that inhibit the production of lithium difluorophosphate.

The reaction temperature in the above reaction is preferably 20°C or higher, preferably 20°C to 150°C, more preferably 20°C to 120°C, even more preferably 20°C to 100°C. .
When the reaction temperature is 20° C. or higher, the production of complex compound 2 is likely to be promoted.
When the reaction temperature is 150° C. or less, the decomposition of the generated complex compound 2 is further suppressed, and the production rate is likely to improve.

The reaction time in the above reaction is preferably from 30 minutes to 12 hours, more preferably from 1 hour to 8 hours, from the viewpoint of allowing the reaction to proceed efficiently.

The reaction in the solution production step may be a reaction to obtain only a solution of complex compound 2, or a reaction to obtain a mixture (for example, slurry) of a solution of complex compound 2 and a solid precipitate.

When the reaction in the solution production step is a reaction to obtain only a solution of complex compound 2, the obtained solution of complex compound 2 may be used as it is for various uses (specific examples of uses will be described later).
In addition, when the reaction in the solution manufacturing process is a reaction to obtain only a solution of complex compound 2, the organic solvent is removed from the solution of complex compound 2 by heating concentration etc. to take out complex compound 2, and the removed complex compound 2 is , may be used for various purposes.

When the solution manufacturing process is a reaction to obtain a mixture of a solution of complex compound 2 and a solid precipitate, the solid precipitate obtained by removing the solid precipitate from the mixture by filtration, centrifugation, sedimentation, etc. A solution of complex compound 2 can be used for various purposes.
That is, the solution manufacturing step includes a step of obtaining a mixture of a solution of complex compound 2 and a solid precipitate by reacting boron oxide, lithium hexafluorophosphate, and lithium fluoride in an organic solvent; and removing solid precipitates.
Examples of solid precipitates include lithium difluorophosphate.

Manufacturing method A may include steps other than the solution manufacturing step.
Other steps include a step of taking out complex compound 2 from the solution of complex compound 2 obtained in the solution manufacturing step.

As a method for removing complex compound 2 from a solution of complex compound 2, heating concentration is suitable.
The heating temperature in heating concentration is preferably 40°C to 150°C, more preferably 40°C to 100°C, even more preferably 50°C to 70°C.
When the heating temperature is 40° C. or higher, the extraction efficiency of the complex compound 2 is excellent.
When the heating temperature is 150° C. or less, it is easy to stably take out the complex compound 2.
Heat concentration can be performed under normal pressure or reduced pressure.
When heat concentration is performed under reduced pressure, the pressure is preferably 10 kPa or less.

As a method for drying the complex compound 2 taken out in the taking out step, any conventionally known method can be selected and carried out.
Drying methods include, for example, static drying using a tray dryer; fluidized drying using a conical dryer; drying using a device such as a hot plate or oven; hot air drying using a dryer such as a dryer. or a method of supplying hot air; etc.

The removed complex compound 2 can be dried under normal pressure or reduced pressure.
When drying is performed under reduced pressure, the pressure is preferably 10 kPa or less.
The drying temperature when drying the extracted complex compound 2 is preferably 20°C to 150°C, more preferably 20°C to 100°C, even more preferably 40°C to 80°C, More preferably, the temperature is 50°C to 70°C.
Drying efficiency is excellent when the drying temperature is 20°C or higher.
When the drying temperature is 150° C. or lower, it is easy to stably dry the complex compound 2.

The lithium salt complex compound (complex compound 2) or its solution obtained by the production method A explained above can be used as an additive for lithium ion batteries, a reaction reagent, a synthesis reaction catalyst, an electrolyte for various electrochemical devices, a doping agent, and a lubricating oil. It can be usefully used as an additive.
The lithium salt complex compound (complex compound 2) obtained by production method A or its solution is especially suitable when used as an additive added to a non-aqueous electrolyte for batteries (preferably a non-aqueous electrolyte for lithium secondary batteries). , is expected to contribute to improving battery characteristics.
In this case, a solution of complex compound 2 may be used as part of the raw material to prepare a non-aqueous electrolyte for batteries, or a solution of complex compound 2 taken out from the solution of complex compound 2 may be used as part of the raw material to prepare a battery. You may prepare a non-aqueous electrolyte for use.

Examples of the present disclosure will be shown below, but the present disclosure is not limited to the following examples.
In addition, in the following examples, the lithium salt complex compound is also simply referred to as a "complex compound." The numbers of the complex compounds correspond to the numbers of the complex compounds described above.

[Example 1] Complex compound 1 consisting of lithium hexafluorophosphate and lithium difluorophosphate
After purging with dry nitrogen gas, 3.24 g (0.03 mol) of lithium difluorophosphate and 20 g of ethyl acetate were placed in a 50 mL flask equipped with a stirrer, thermometer, gas introduction and exhaust lines, and the mixture was stirred at room temperature. to dissolve lithium difluorophosphate. 4.56 g (0.03 mol) of lithium hexafluorophosphate was added to this solution, and after stirring for 1 hour, the pressure was reduced to 10 kPa or less and the mixture was heated to 60° C. while stirring to distill off ethyl acetate. The obtained solid was further dried at 60° C. under a reduced pressure of 10 kPa or less to obtain 7.80 g of a solid product.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
^19F -NMR: -72ppm (3F), -74ppm (3F). -82ppm (1F), -85ppm (1F).
A pattern combining the spectral patterns of lithium difluorophosphate and lithium hexafluorophosphate alone was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a peak of 132°C was observed, which was not observed when both raw material compounds were measured individually.
Note that the endothermic dissociation behavior was observed using a differential scanning calorimeter (Model DSC220C) manufactured by Seiko Instruments Inc. The same applies below.

[Example 2] Complex compound 2 consisting of lithium tetrafluoroborate and lithium difluorophosphate
In carrying out the same method as in Example 1, the treatment was performed by changing lithium hexafluorophosphate to 2.81 g (0.03 mol) of lithium tetrafluoroborate. Finally, 6.05 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
¹⁹ F-NMR: -82ppm (1F), -85ppm (1F), -153ppm (4F).
A pattern combining the spectral patterns of lithium difluorophosphate and lithium tetrafluoroborate alone was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a peak of 140°C was observed, which was not observed when both raw material compounds were measured individually.

[Example 3] Complex compound 3 consisting of lithium bis(oxalato)borate and lithium difluorophosphate
The same method as in Example 1 was carried out, except that lithium hexafluorophosphate was changed to 5.81 g (0.03 mol) of lithium bis(oxalato)borate. Finally, 9.05 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] of the obtained spectrum was as follows.
^19F -NMR: -82ppm, -85ppm.
¹¹ B-NMR analysis was also conducted, and the chemical shifts [ppm] of the obtained spectrum were as follows.
^11B -NMR: 6.5 ppm.
Spectral patterns identical to those of lithium difluorophosphate and lithium bis(oxalato)borate alone were confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, endothermic dissociation behavior with a peak of 179°C was observed, which was not observed when both raw material compounds were measured individually.

[Example 4] Complex compound 4 consisting of lithium trifluoromethanesulfonate and lithium difluorophosphate
In carrying out the same method as in Example 1, lithium hexafluorophosphate was changed to 4.68 g (0.03 mol) of lithium trifluoromethanesulfonate. Finally, 7.91 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
^19F -NMR: -78ppm (3F), -82ppm (1F), -85ppm (1F).
A pattern combining the spectral patterns of lithium difluorophosphate and lithium trifluoromethanesulfonate alone was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a peak of 222°C was observed, which was not observed when both raw material compounds were measured individually.

[Example 5] Complex compound 5 consisting of lithium methyl sulfate and lithium difluorophosphate
The same method as in Example 1 was carried out, except that lithium hexafluorophosphate was changed to 3.54 g (0.03 mol) of lithium methyl sulfate. Finally, 6.78 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹ H-NMR analysis. The chemical shift [ppm] of the obtained spectrum was as follows.
¹ H-NMR: 3.5 ppm.
¹⁹ F-NMR analysis was also conducted, and the chemical shifts [ppm] of the obtained spectrum were as follows.
^19F -NMR: -82ppm, -85ppm.
Spectral patterns identical to those of lithium methyl sulfate and lithium difluorophosphate alone were confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a peak of 240°C was observed, which was not observed when both raw material compounds were measured individually.

[Example 6] Complex compound 6 consisting of lithium benzenesulfonate and lithium difluorophosphate
In carrying out the same method as in Example 1, the treatment was performed by changing lithium hexafluorophosphate to 4.92 g (0.03 mol) of lithium benzenesulfonate. Finally, 8.15 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹ H-NMR analysis. The chemical shift [ppm] of the obtained spectrum was as follows.
¹ H-NMR: 7.5-7.9 ppm.
¹⁹ F-NMR analysis was also conducted, and the chemical shifts [ppm] of the obtained spectrum were as follows.
^19F -NMR: -82ppm, -85ppm.
Spectral patterns identical to those of lithium benzenesulfonate and lithium difluorophosphate alone were confirmed, respectively, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a 320° C. peak that was not observed when both raw material compounds were measured individually was observed.

[Example 7] Complex compound 7 consisting of lithium bis(trifluoromethanesulfonyl)imide and lithium difluorophosphate
The same method as in Example 1 was carried out, except that lithium hexafluorophosphate was replaced with 8.61 g (0.03 mol) of lithium bis(trifluoromethanesulfonyl)imide. Finally, 11.85 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
^19F -NMR: -79ppm (6F), -82ppm (1F), -85ppm (1F).
A pattern combining the spectral patterns of lithium difluorophosphate and lithium bis(trifluoromethanesulfonyl)imide alone was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a 244° C. peak that was not observed when both raw material compounds were measured individually was observed.

[Example 8] Complex compound 8 consisting of lithium bis(fluorosulfonyl)imide and lithium difluorophosphate
The same method as in Example 1 was carried out, except that lithium hexafluorophosphate was replaced with 5.61 g (0.03 mol) of lithium bis(fluorosulfonyl)imide. Finally, 8.85 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
^19F -NMR: 55ppm (2F), -82ppm (1F), -85ppm (1F).
A pattern combining the spectral patterns of lithium difluorophosphate and lithium bis(fluorosulfonyl)imide alone was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a 200° C. peak was observed, which was not observed when both raw material compounds were measured individually.

[Example 9] Complex compound 9 consisting of lithium bis(perfluoroethylsulfonyl)imide and lithium difluorophosphate
The same method as in Example 1 was carried out, except that lithium hexafluorophosphate was replaced with 11.61 g (0.03 mol) of lithium bis(perfluoroethylsulfonyl)imide. Finally, 14.84 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
¹⁹ F-NMR: -80ppm (6F), -82ppm (1F), -85ppm (1F), -119ppm (4F).
A pattern combining the spectral patterns of lithium difluorophosphate and lithium bis(perfluoroethylsulfonyl)imide alone was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a peak of 288°C was observed, which was not observed when both raw material compounds were measured individually.

[Example 10] Complex compound 10 consisting of lithium tetrafluoroborate and lithium hexafluorophosphate
After purging with dry nitrogen gas, 4.56 g (0.03 mol) of lithium hexafluorophosphate and 20 g of ethyl acetate were placed in a 50 mL flask equipped with a stirrer, a thermometer, and gas inlet and exhaust lines at room temperature. The mixture was stirred to dissolve the lithium hexafluorophosphate. 2.81 g (0.03 mol) of lithium tetrafluoroborate was added to this solution, and after stirring for 1 hour, the pressure was reduced to 10 kPa or less and the mixture was heated to 60° C. while stirring to distill off ethyl acetate. The obtained solid was further dried at 60° C. under a reduced pressure of 10 kPa or less to obtain 7.36 g of a solid product.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
^19F -NMR: -72ppm (3F), -74ppm (3F), -153ppm (4F).
A combined spectral pattern of lithium hexafluorophosphate and lithium tetrafluoroborate was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, endothermic dissociation behavior with a 97°C peak was observed, which was not observed when both raw material compounds were measured individually.

[Example 11] Complex compound 11 consisting of lithium bis(oxalato)borate and lithium hexafluorophosphate
The same method as in Example 10 was carried out, except that lithium tetrafluoroborate was changed to 5.81 g (0.03 mol) of lithium bis(oxalato)borate. Finally, 10.36 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] of the obtained spectrum was as follows.
^19F -NMR: -72ppm, -74ppm.
¹¹ B-NMR analysis was also conducted, and the chemical shifts [ppm] of the obtained spectrum were as follows.
^11B -NMR: 6.5 ppm.
Spectral patterns identical to those of lithium hexafluorophosphate and lithium bis(oxalato)borate alone were confirmed, respectively, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a peak of 140°C was observed, which was not observed when both raw material compounds were measured individually.

[Example 12] Complex compound 12 consisting of lithium trifluoromethanesulfonate and lithium hexafluorophosphate
In carrying out the same method as in Example 10, the treatment was performed by changing lithium tetrafluoroborate to 4.68 g (0.03 mol) of lithium trifluoromethanesulfonate. Finally, 9.24 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
¹⁹ F-NMR: -72ppm (3F), -74ppm (3F), -78ppm (3F).
A pattern combining the spectral patterns of lithium hexafluorophosphate and lithium trifluoromethanesulfonate alone was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a peak of 165°C was observed, which was not observed when both raw material compounds were measured individually.

[Example 13] Complex compound 13 consisting of lithium methyl sulfate and lithium hexafluorophosphate
The same method as in Example 10 was carried out, except that lithium tetrafluoroborate was changed to 3.54 g (0.03 mol) of lithium methyl sulfate. Finally, 8.10 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹ H-NMR analysis. The chemical shift [ppm] of the obtained spectrum was as follows.
¹ H-NMR: 3.5 ppm.
¹⁹ F-NMR analysis was also conducted, and the chemical shifts [ppm] of the obtained spectrum were as follows.
^19F -NMR: -72ppm, -74ppm.
Spectral patterns identical to those of lithium methyl sulfate and lithium hexafluorophosphate alone were confirmed, indicating that the products have both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, endothermic dissociation behavior with a peak of 196°C was observed, which was not observed when both raw material compounds were measured alone.

[Example 14] Complex compound 14 consisting of lithium benzenesulfonate and lithium hexafluorophosphate
In carrying out the same method as in Example 10, the treatment was performed by changing lithium tetrafluoroborate to 4.92 g (0.03 mol) of lithium benzenesulfonate. Finally, 9.48 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹ H-NMR analysis. The chemical shift [ppm] of the obtained spectrum was as follows.
¹ H-NMR: 7.5-7.9 ppm.
¹⁹ F-NMR analysis was also conducted, and the chemical shifts [ppm] of the obtained spectrum were as follows.
^19F -NMR: -72ppm, -74ppm.
Spectral patterns identical to those of lithium benzenesulfonate and lithium hexafluorophosphate alone were confirmed, respectively, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a peak of 214°C was observed, which was not observed when both raw material compounds were measured alone.

[Example 15] Complex compound 15 consisting of lithium bis(trifluoromethanesulfonyl)imide and lithium hexafluorophosphate
The same method as in Example 10 was carried out, except that lithium tetrafluoroborate was replaced with 8.61 g (0.03 mol) of lithium bis(trifluoromethanesulfonyl)imide. Finally, 13.17 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
^19F -NMR: -72ppm (3F), -74ppm (3F), -79ppm (6F).
A combined spectral pattern of lithium hexafluorophosphate and lithium bis(trifluoromethanesulfonyl)imide alone was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a peak of 224°C was observed, which was not observed when both raw material compounds were measured individually.

[Example 16] Complex compound 16 consisting of lithium bis(fluorosulfonyl)imide and lithium hexafluorophosphate
The same method as in Example 10 was carried out, except that lithium tetrafluoroborate was replaced with 5.61 g (0.03 mol) of lithium bis(fluorosulfonyl)imide. Finally, 10.16 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
^19F -NMR: 55ppm (2F), -72ppm (3F), -74ppm (3F).
A pattern combining the spectral patterns of lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide alone was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a peak of 333°C was observed, which was not observed when both raw material compounds were measured individually.

[Example 17] Complex compound 17 consisting of lithium bis(perfluoroethylsulfonyl)imide and lithium hexafluorophosphate
The same method as in Example 10 was carried out, except that lithium tetrafluoroborate was replaced with 11.61 g (0.03 mol) of lithium bis(perfluoroethylsulfonyl)imide. Finally, 16.16 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
¹⁹ F-NMR: -72ppm (3F), -74ppm (3F), -80ppm (6F), -119ppm (4F).
A pattern combining the spectral patterns of lithium hexafluorophosphate and lithium bis(perfluoroethylsulfonyl)imide alone was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a 245° C. peak that was not observed when both raw material compounds were measured individually was observed.

[Example 18] Complex compound 18 consisting of lithium bis(oxalato)borate and lithium tetrafluoroborate
After purging with dry nitrogen gas, 2.81 g (0.03 mol) of lithium tetrafluoroborate and 20 g of ethyl acetate were placed in a 50 mL flask equipped with a stirrer, thermometer, gas introduction and exhaust lines, and mixed with stirring. I let it happen. 5.81 g (0.03 mol) of lithium bis(oxalato)borate was added to this liquid, and after stirring for 1 hour, the pressure was reduced to 10 kPa or less and heated to 60°C while stirring to distill off ethyl acetate. . The obtained solid was further dried at 60° C. under a reduced pressure of 10 kPa or less to obtain 8.62 g of a solid product.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] of the obtained spectrum was as follows.
^19F -NMR: -153ppm.
¹¹ B-NMR analysis was also conducted, and the chemical shifts [ppm] of the obtained spectrum were as follows.
^11B -NMR: 6.5ppm, -2.4ppm.
The spectral pattern of lithium tetrafluoroborate was confirmed by ¹⁹ F-NMR, and the combined spectral pattern of lithium tetrafluoroborate and lithium bis(oxalato)borate alone was confirmed by ¹¹ B-NMR. It was shown that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, endothermic dissociation behavior with a 97°C peak was observed, which was not observed when both raw material compounds were measured individually.

[Example 19] Complex compound 19 consisting of lithium trifluoromethanesulfonate and lithium tetrafluoroborate
In carrying out the same method as in Example 18, the treatment was performed by changing lithium bis(oxalato)borate to 4.68 g (0.03 mol) of lithium trifluoromethanesulfonate. Finally, 7.49 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
^19F -NMR: -78ppm (3F), -153ppm (4F).
A pattern combining the spectral patterns of lithium tetrafluoroborate and lithium trifluoromethanesulfonate alone was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a peak of 118°C was observed, which was not observed when both raw material compounds were measured individually.

[Example 20] Complex compound 20 consisting of lithium methyl sulfate and lithium tetrafluoroborate
The same method as in Example 18 was carried out, except that lithium bis(oxalato)borate was changed to 3.54 g (0.03 mol) of lithium methyl sulfate. Finally, 6.34 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹ H-NMR analysis. The chemical shift [ppm] of the obtained spectrum was as follows.
¹ H-NMR: 3.5 ppm.
¹⁹ F-NMR analysis was also conducted, and the chemical shifts [ppm] of the obtained spectrum were as follows.
^19F -NMR: -153ppm.
Spectral patterns identical to those of lithium methyl sulfate and lithium tetrafluoroborate alone were confirmed, respectively, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a peak of 140°C was observed, which was not observed when both raw material compounds were measured individually.

[Example 21] Complex compound 21 consisting of lithium benzenesulfonate and lithium tetrafluoroborate
The same method as in Example 18 was carried out, except that lithium bis(oxalato)borate was replaced with 4.92 g (0.03 mol) of lithium benzenesulfonate. Finally, 7.72 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹ H-NMR analysis. The chemical shift [ppm] of the obtained spectrum was as follows.
¹ H-NMR: 7.5-7.9 ppm.
¹⁹ F-NMR analysis was also conducted, and the chemical shifts [ppm] of the obtained spectrum were as follows.
^19F -NMR: -153ppm.
Spectral patterns identical to those of lithium benzenesulfonate and lithium tetrafluoroborate alone were confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a 105° C. peak that was not observed when both raw material compounds were measured individually was observed.

[Example 22] Complex compound 22 consisting of lithium bis(trifluoromethanesulfonyl)imide and lithium tetrafluoroborate
The same method as in Example 18 was carried out, except that lithium bis(oxalato)borate was replaced with 8.61 g (0.03 mol) of lithium bis(trifluoromethanesulfonyl)imide. Finally, 11.42 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
^19F -NMR: -79ppm (6F), -153ppm (4F).
A pattern combining the spectral patterns of lithium tetrafluoroborate and lithium bis(trifluoromethanesulfonyl)imide alone was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, endothermic dissociation behavior with a 300°C peak was observed, which was not observed when both raw material compounds were measured individually.

[Example 23] Complex compound 23 consisting of lithium bis(fluorosulfonyl)imide and lithium tetrafluoroborate
The same method as in Example 18 was carried out, except that lithium bis(oxalato)borate was replaced with 5.61 g (0.03 mol) of lithium bis(fluorosulfonyl)imide. Finally, 8.41 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
¹⁹ F-NMR: 55 ppm (2F), -153 ppm (4F).
A pattern combining the spectral patterns of lithium tetrafluoroborate and lithium bis(fluorosulfonyl)imide alone was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a peak of 120°C was observed, which was not observed when both raw material compounds were measured individually.

[Example 24] Complex compound 24 consisting of lithium bis(perfluoroethylsulfonyl)imide and lithium tetrafluoroborate
The same method as in Example 18 was carried out, except that lithium bis(oxalato)borate was replaced with 11.61 g (0.03 mol) of lithium bis(perfluoroethylsulfonyl)imide. Finally, 14.42 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
^19F -NMR: -80ppm (6F), -119ppm (4F), -153ppm (4F).
A pattern combining the spectral patterns of lithium tetrafluoroborate and lithium bis(perfluoroethylsulfonyl)imide alone was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a peak of 180°C was observed, which was not observed when both raw material compounds were measured individually.

[Example 25] Complex compound 25 consisting of lithium fluorosulfonate and lithium difluorophosphate
The same method as in Example 1 was carried out, except that lithium hexafluorophosphate was changed to 3.18 g (0.03 mol) of lithium fluorosulfonate. Finally, 6.42 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
^19F -NMR: 40ppm (1F), -82ppm (1F), -85ppm (1F).
A pattern combining the spectral patterns of lithium fluorosulfonate and lithium difluorophosphate alone was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a peak of 167°C was observed, which was not observed when both raw material compounds were measured individually.

[Example 26] Complex compound 26 consisting of lithium fluorosulfonate and lithium hexafluorophosphate
The same method as in Example 10 was carried out, except that lithium tetrafluoroborate was changed to 3.18 g (0.03 mol) of lithium fluorosulfonate. Finally, 7.74 g of a solid product was obtained.

The obtained solid was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
^19F -NMR: 40ppm (1F), -72ppm (3F), -74ppm (3F).
A pattern combining the spectral patterns of lithium fluorosulfonate and lithium hexafluorophosphate alone was confirmed, indicating that the product has both structural units.
Further, the obtained solid was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. In the obtained solid, an endothermic dissociation behavior with a 125° C. peak that was not observed when both raw material compounds were measured individually was observed.

As shown above, novel lithium salt complex compounds were obtained in each Example.
In addition, endothermic dissociation behavior was observed in the lithium salt complex compounds obtained in each example at temperatures that were not observed in the raw material compounds (specific lithium salts and specific compounds). That is, it was confirmed that the obtained lithium salt complex compound has excellent thermal stability.

Next, Examples 101 and 102, which are examples of the aforementioned manufacturing method A (one aspect of the method for manufacturing a lithium salt complex compound that is complex compound 2), will be shown.

[Example 101]
After purging with dry nitrogen gas, a 100 mL flask equipped with a stirrer, a thermometer, a gas inlet line, and an exhaust line was charged with 1.66 g (0.024 mol) of boron oxide and 1.24 g (0.0 mol) of lithium fluoride. 048 mol) and 23.50 g of dimethyl carbonate were added and stirred at room temperature (25°C. The same applies hereinafter) to obtain a slurry. A solution of 5.45 g (0.036 mol) of lithium hexafluorophosphate dissolved in 16.35 g of dimethyl carbonate was added dropwise over 1 hour to obtain a mixed solution containing all the raw materials. . This mixed solution was stirred at 25° C. for 12 hours to carry out a reaction to obtain a reaction solution. The resulting reaction solution was a slurry in which solids were precipitated. By filtering this reaction solution (slurry), solution A (47.69 g) was obtained as a filtrate. Dimethyl carbonate was distilled off from solution A by heating this solution A to 60° C. under a reduced pressure of 10 kPa or less to obtain a solid. The obtained solid was further dried at 60° C. under reduced pressure of 10 kPa or less to obtain 7.85 g of a solid product.

The obtained solid product was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
^19F -NMR: -82.0ppm (1F), -84.5ppm (1F), -153.0ppm (6.1F).

¹¹ B-NMR analysis of the solid product was also conducted. The chemical shift [ppm] of the obtained spectrum was as follows.
^11B -NMR: -2.4ppm.

¹⁹ F-NMR confirmed a spectrum pattern that combined the spectrum pattern of lithium difluorophosphate alone and the spectrum pattern of lithium tetrafluoroborate alone, and the spectrum pattern of lithium tetrafluoroborate was confirmed by ¹¹ B-NMR. was confirmed. Furthermore, from the integral value ratio in ¹⁹ F-NMR, this solid product is composed of lithium tetrafluoroborate and lithium difluorophosphate, with a molar ratio [lithium tetrafluoroborate/lithium difluorophosphate] of 1.5. It was shown that it is configured.

Further, the obtained solid product was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. As a result, an endothermic dissociation behavior with a peak of 146°C was observed, which was not observed when measuring each of lithium tetrafluoroborate and lithium difluorophosphate alone.

From the above results, it is clear that the solid product obtained in Example 101 is complex compound 2 consisting of lithium tetrafluoroborate and lithium difluorophosphate (molar ratio [lithium tetrafluoroborate/lithium difluorophosphate] = 1). .5) was confirmed.

[Example 102]
After purging a 100 mL flask equipped with a stirrer, a thermometer, a gas inlet line, and an exhaust line with dry nitrogen gas, 1.66 g (0.024 mol) of boron oxide and 23.50 g of dimethyl carbonate were charged therein. The slurry was stirred while being heated to 90°C (88°C reflux state) to obtain a slurry. A solution of 5.45 g (0.036 mol) of lithium hexafluorophosphate dissolved in 16.35 g of dimethyl carbonate was added dropwise over 1 hour. Immediately after all of the above solution was dropped, the slurry had changed into a homogeneous solution in which boron oxide was dissolved. Subsequently, 1.24 g (0.048 mol) of lithium fluoride was quickly added thereto to prepare a liquid mixture containing all the raw materials. Subsequently, this mixed solution was stirred at 90° C. (88° C. reflux state) for 1 hour to carry out a reaction, and a reaction solution was obtained. The resulting reaction solution was a slurry in which solids were precipitated. This reaction solution (slurry) was cooled to room temperature and then filtered to obtain solution A (47.74 g) as a filtrate. Dimethyl carbonate was distilled off from solution A by heating this solution A to 60° C. under a reduced pressure of 10 kPa or less to obtain a solid. The obtained solid was further dried at 60° C. under reduced pressure of 10 kPa or less to obtain 7.88 g of a solid product.

The obtained solid product was dissolved in a heavy water solvent and subjected to ¹⁹ F-NMR analysis. The chemical shift [ppm] and (integral value (ratio)) of the obtained spectrum were as follows.
^19F -NMR: -82.0ppm (1F), -84.5ppm (1F), -153.0ppm (6.0F).

¹¹ B-NMR analysis of the solid product was also conducted. The chemical shift [ppm] of the obtained spectrum was as follows.
^11B -NMR: -2.4ppm.

¹⁹ F-NMR confirmed a spectrum pattern that combined the spectrum pattern of lithium difluorophosphate alone and the spectrum pattern of lithium tetrafluoroborate alone, and the spectrum pattern of lithium tetrafluoroborate was confirmed by ¹¹ B-NMR. was confirmed. Furthermore, from the integral value ratio in ¹⁹ F-NMR, this solid product is composed of lithium tetrafluoroborate and lithium difluorophosphate, with a molar ratio [lithium tetrafluoroborate/lithium difluorophosphate] of 1.5. It was shown that it is configured.

Further, the obtained solid product was subjected to differential scanning calorimetry (DSC) measurement from room temperature to 600°C. As a result, an endothermic dissociation behavior with a peak of 146°C was observed, which was not observed when measuring each of lithium tetrafluoroborate and lithium difluorophosphate alone.

From the above results, the solid product obtained in Example 102 is also the complex compound 2 consisting of lithium tetrafluoroborate and lithium difluorophosphate (molar ratio [lithium tetrafluoroborate/lithium difluorophosphate] = 1). .5) was confirmed.

In addition, ¹¹ B-NMR analysis was also performed on Complex Compound 2 produced in Example 2, and the chemical shifts [ppm] of the obtained spectrum were as follows.
^11B -NMR: -2.4ppm.
Complex Compound 2 produced in Example 2 is composed of lithium tetrafluoroborate and lithium difluoroborate whose molar ratio [lithium tetrafluoroborate/lithium difluorophosphate] is 1.0 from the integral value ratio of ¹⁹ F-NMR described above. It can be seen that it is composed of lithium difluorophosphate.

According to the above-mentioned Examples 101 and 102, the complex compound 2 of Example 2 was prepared by the above-mentioned production method A except for the molar ratio [lithium tetrafluoroborate/lithium difluorophosphate] (molar ratio [lithium tetrafluoroborate/lithium difluorophosphate]). It was confirmed that a complex compound 2 (molar ratio [lithium tetrafluoroborate/lithium difluorophosphate] = 1.5) having a structure similar to that of lithium oxide (lithium oxide) = 1.0) was produced.

Claims (7)

A solid containing a lithium salt complex compound consisting of lithium tetrafluoroborate and lithium difluorophosphate,
Obtained by removing the precipitate from a mixture containing a solution in which the lithium salt complex compound is dissolved in an organic solvent and a precipitate consisting of lithium difluorophosphate, and then distilling off the organic solvent. solid. An additive for lithium secondary batteries comprising the solid according to claim 1 . A method for producing a lithium salt complex compound consisting of lithium tetrafluoroborate and lithium difluorophosphate, the method comprising:
A method for producing a lithium salt complex compound, comprising the step of obtaining a solution of the lithium salt complex compound by reacting boron oxide, lithium hexafluorophosphate, and lithium fluoride in an organic solvent. The method for producing a lithium salt complex compound according to claim 3, wherein the reaction temperature in the reaction of the boron oxide, the lithium hexafluorophosphate, and the lithium fluoride is 20° C. or higher. The step of obtaining a solution of the lithium salt complex compound includes:
obtaining a mixture of a solution of the lithium salt complex compound and a solid precipitate by reacting boron oxide, lithium hexafluorophosphate, and lithium fluoride in an organic solvent;
removing the solid precipitate from the mixture;
The method for producing a lithium salt complex compound according to claim 3 or 4, comprising: The method for producing a lithium salt complex compound according to any one of claims 3 to 5, further comprising a step of taking out the lithium salt complex compound from the solution of the lithium salt complex compound. The organic solvent is acetone, methyl ethyl ketone, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, acetonitrile, propionitrile, dimethoxyethane, diethylene glycol dimethyl ether, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene carbonate. The method for producing a lithium salt complex compound according to any one of claims 3 to 6, wherein the lithium salt complex compound is at least one selected from the group consisting of , propylene carbonate, and fluoroethylene carbonate.