The invention relates to a new method for producing an onium salt of bis(fluorosulfonyl)imide and an alkali metal salt of bis(fluorosulfonyl)imide of high purities, as industrial scale, and with a reasonable cost when compared to the other available methods. Said method comprises the steps of reacting bis(chlorosulfonyl)imide or salts thereof with an onium halide other than an onium fluoride to produce an onium salt of bis(chlorosulfonyl)imide, reacting the onium salt of bis(chlorosulfonyl)imide with an onium fluoride to produce an onium salt of bis(fluorosulfonyl)imide; the onium salt of bis(fluorosulfonyl)imide may be further reacted with an alkali metal salt to obtain an alkali metal salt of bis(fluorosulfonyl)imide.

A method for drying and purifying a lithium bis(fluorosulfonyl)imide salt. Also, a method for producing a lithium bis(fluorosulfonyl)imide salt which is then dried and purified by the method. Further, a composition containing lithium bis(fluorosulfonyl)imide salt having a water content by mass of between 5 and 45 ppm. And, the use of the composition C in Li-ion batteries.

The present invention relates to bis(fluorosulfonyl)imide salts, and their preparation methods. More specifically, the invention provides a new salt of bis(fluorosulfonyl)imide containing from 0.01 ppm to 10000 ppm of a halogenated alcohol. The invention further relates to a method for producing said salt of bis(fluorosulfonyl)imide, said method comprising a step of crystallizing a raw salt of bis(fluorosulfonyl)imide within a crystallization solvent comprising at least a halogenated alcohol. The use of said salt of bis(fluorosulfonyl)imide is also disclosed.

The present invention relates to bis(fluorosulfonyl)imide salts, and their preparation methods. More specifically, the invention provides a new salt of bis(fluorosulfonyl)imide containing from 0.01 ppm to 10000 ppm of a halogenated alcohol. The invention further relates to a method for producing said salt of bis(fluorosulfonyl)imide, said method comprising a step of crystallizing a raw salt of bis(fluorosulfonyl)imide within a crystallization solvent comprising at least a halogenated alcohol. The use of said salt of bis(fluorosulfonyl)imide is also disclosed.

Provided is a method the enables easy production of bis(fluorosulfonyl)imide suitable for a non-aqueous electrolytic solution for a lithium ion secondary battery, etc. The method for producing a bis(fluorosulfonyl)imide alkali metal salt according to the present invention comprises reacting bis(fluorosulfonyl)imide with an alkali metal compound in a reaction solution containing an organic solvent, wherein the organic solvent includes at least one organic solvent (A) selected from the group consisting of carbonate solvents, cyclic ether solvents, linear ether solvents having two or more oxygen atoms in the molecule, cyclic ester solvents, sulfolane solvents, N,N-dimethyl formamide, dimethyl sulfoxide, and N-methyl oxazolidinone.

Provided is a method the enables easy production of bis(fluorosulfonyl)imide suitable for a non-aqueous electrolytic solution for a lithium ion secondary battery, etc. The method for producing a bis(fluorosulfonyl)imide alkali metal salt according to the present invention comprises reacting bis(fluorosulfonyl)imide with an alkali metal compound in a reaction solution containing an organic solvent, wherein the organic solvent includes at least one organic solvent (A) selected from the group consisting of carbonate solvents, cyclic ether solvents, linear ether solvents having two or more oxygen atoms in the molecule, cyclic ester solvents, sulfolane solvents, N,N-dimethyl formamide, dimethyl sulfoxide, and N-methyl oxazolidinone.

Provided is a method with which it is possible to conveniently produce bis(fluorosulfonyl)imide suitable as a nonaqueous electrolyte of a lithium ion secondary cell. The method for producing a bis(fluorosulfonyl)imide alkali metal salt of the invention is a production method for producing a bis(fluorosulfonyl)imide alkali metal salt by reacting bis(fluorosulfonyl)imide and an alkali metal halide in a reaction solution including an organic solvent, the method including a purification step for filtering out the bis(fluorosulfonyl)imide alkali metal from the solution after the reaction.

A method for producing a bis(fluorosulfonyl)imide lithium salt is disclosed. The method includes the steps of: (a) reacting bis(chlorosulfonyl)imide with NH.sub.4F(HF)n (n=0-10) to prepare ammonium bis(fluorosulfonyl)imide; and (b) reacting the ammonium bis(fluorosulfonyl)imide with a lithium base, wherein in at least one of steps (a) and (b), after the reaction, a process of adding an alkoxy trialkyl silane to the reaction solution to remove a fluorine anion is performed.

A method for producing a bis(fluorosulfonyl)imide lithium salt is disclosed. The method includes the steps of: (a) reacting bis(chlorosulfonyl)imide with NH.sub.4F(HF)n (n=0-10) to prepare ammonium bis(fluorosulfonyl)imide; and (b) reacting the ammonium bis(fluorosulfonyl)imide with a lithium base, wherein in at least one of steps (a) and (b), after the reaction, a process of adding an alkoxy trialkyl silane to the reaction solution to remove a fluorine anion is performed.

A method for efficiently removing impurities such as sodium ions, fluoride ions, chloride ions and fluorosulfate ions without reducing the yield of a target product, including a fluorine-containing sulfonylamide compound selected from the group consisting of fluorine-containing sulfonylamide, a metal salt thereof, an ammonium salt thereof and a quaternary ammonium salt thereof is washed with an aqueous solution of salt of sulfuric acid.