An object of the present invention is to provide a method for producing a bis(fluorosulfonyl)amide alkali metal salt powder having high purity while suppressing reduction in yield due to thermal decomposition, etc. The method for producing a bis(fluorosulfonyl)amide alkali metal salt powder according to the present invention comprises precipitating a bis(fluorosulfonyl)amide alkali metal salt by conducting distillation using a thin-film evaporator while adding a poor solvent for the bis(fluorosulfonyl)amide alkali metal salt such as an aromatic hydrocarbon solvent and a linear or branched aliphatic hydrocarbon solvent to a solution formed by dissolving the bis(fluorosulfonyl)amide alkali metal salt in a good solvent for the bis(fluorosulfonyl)amide alkali metal salt such as an ester solvent and nitrile solvent.

Methods for making high-purity LiFSI salts and intermediate products using one, the other, or both of a reactive-solvent removal/replacement method and an LiFSI purification method. In some embodiments, the reactive-solvent removal/replacement method includes using non-reactive anhydrous organic solvents to remove and/or replace one or more reactive solvents in a crude LiFSI. In some embodiments, the LiFSI purification method includes using anhydrous organic solvents to remove impurities, such as synthesis impurities, from a crude LiFSI. In some embodiments, crude LiFSI can be made using an aqueous-based neutralization process. LiFSI salts and products made using methods of the disclosure are also described, as are uses of such salts and products and electrochemical devices that include such salts and products.

Methods for making high-purity LiFSI salts and intermediate products using one, the other, or both of a reactive-solvent removal/replacement method and an LiFSI purification method. In some embodiments, the reactive-solvent removal/replacement method includes using non-reactive anhydrous organic solvents to remove and/or replace one or more reactive solvents in a crude LiFSI. In some embodiments, the LiFSI purification method includes using anhydrous organic solvents to remove impurities, such as synthesis impurities, from a crude LiFSI. In some embodiments, crude LiFSI can be made using an aqueous-based neutralization process. LiFSI salts and products made using methods of the disclosure are also described, as are uses of such salts and products and electrochemical devices that include such salts and products.

A method for producing a lithium sulfamate which includes (1) reacting a compound (1) represented by the following formula (1):

##STR00001##

wherein X is fluorine, chlorine, bromine, or iodine, with a compound (2) represented by the following formula (2):

##STR00002##

wherein R.sup.1 and R.sup.2 are each individually H or a substituent as defined herein, the substituent optionally containing at least one bi- to hexavalent heteroatom in the structure and being a substituent in which at least one hydrogen atom is optionally replaced with a fluorine atom or a C0-C7 functional group, to obtain a compound (3) represented by the following formula (3):

##STR00003##

wherein R.sup.1 and R.sup.2 are defined as above.

A method for producing a lithium sulfamate which includes (1) reacting a compound (1) represented by the following formula (1):

##STR00001##

wherein X is fluorine, chlorine, bromine, or iodine, with a compound (2) represented by the following formula (2):

##STR00002##

wherein R.sup.1 and R.sup.2 are each individually H or a substituent as defined herein, the substituent optionally containing at least one bi- to hexavalent heteroatom in the structure and being a substituent in which at least one hydrogen atom is optionally replaced with a fluorine atom or a C0-C7 functional group, to obtain a compound (3) represented by the following formula (3):

##STR00003##

wherein R.sup.1 and R.sup.2 are defined as above.

Methods of removing target impurities from a crude lithium bis(fluorosulfonyl)imide (LiFSI) to make a purified LiFSI product. In some embodiments, a purification method includes contacting crude LiFSI with a first anhydrous organic solvent to create a solution containing LiFSI and the target impurity(ies), wherein the LiFSI is soluble and the impurity(ies) is/are substantially insoluble. In some embodiments, a second anhydrous organic solvent is added to the solution to precipitate the target impurity(ies), which is then filtered to obtain a filtrate. In some embodiments, solvent is removed from the filtrate to obtain a solid mass containing LiFSI, which may then be contacted with a third anhydrous organic solvent in which the LiFSI is insoluble. The LiFSI may then be isolated from the third anhydrous organic solvent to obtain the purified LiFSI product. Also disclosed are purified LiFSI products and electrochemical devices utilizing purified LiFSI products, among other things.

An electrolytic solution comprising N-(fluorosulfonyl)-N-(fluoroalkylsulfonyl)imide or di(fluorosulfonyl)imide, from which a residual solvent that affects the properties of the electrolyte solution material is reduced, is provided. A method for producing an electrolyte solution material containing fluorosulfonyl imide salt represented by the following general formula (1) and an electrolyte solution preparation solvent comprises decompressing and/or heating a solution containing the fluorosulfonyl imide salt and the electrolyte solution preparation solvent to volatilize a production solvent for the fluorosulfonyl imide salt.

##STR00001##

In general formula (1), R.sub.1 represents a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms, R.sub.2 represents an alkali metal ion.

An electrolytic solution comprising N-(fluorosulfonyl)-N-(fluoroalkylsulfonyl)imide or di(fluorosulfonyl)imide, from which a residual solvent that affects the properties of the electrolyte solution material is reduced, is provided. A method for producing an electrolyte solution material containing fluorosulfonyl imide salt represented by the following general formula (1) and an electrolyte solution preparation solvent comprises decompressing and/or heating a solution containing the fluorosulfonyl imide salt and the electrolyte solution preparation solvent to volatilize a production solvent for the fluorosulfonyl imide salt.

##STR00001##

In general formula (1), R.sub.1 represents a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms, R.sub.2 represents an alkali metal ion.

A process for producing a lithium bis(fluorosulfonyl)imide salt F(SO.sub.2)NLi(SO.sub.2)-F involving a step (b) with a step of fluorinating bis(chlorosulfonyl)imide Cl(SO.sub.2)NH(SO.sub.2)Cl with anhydrous HF, optionally in at least one organic solvent OS1, said step (b) being carried out in a reactor made of a material M3 that is resistant to corrosion, or in a reactor that contains a base layer made of a material M1 coated with a surface layer made of a material M2 that is resistant to corrosion.

A process for producing a lithium bis(fluorosulfonyl)imide salt F(SO.sub.2)NLi(SO.sub.2)-F involving a step (b) with a step of fluorinating bis(chlorosulfonyl)imide Cl(SO.sub.2)NH(SO.sub.2)Cl with anhydrous HF, optionally in at least one organic solvent OS1, said step (b) being carried out in a reactor made of a material M3 that is resistant to corrosion, or in a reactor that contains a base layer made of a material M1 coated with a surface layer made of a material M2 that is resistant to corrosion.