The present disclosure relates to a method for preparing salts of bis(fluorosulfonyl)imide and to a method for preparing alkali metal salts of bis(fluorosulfonyl)imide from said bis(fluorosulfonyl)imide salts. More specifically. the invention provides a new method for producing these salts of bis(fluorosulfonyl)imide which is implementable at industrial scale and providing high-purity bis(fluorosulfonyl)imide salts.

A method of purifying a crude lithium bis(fluorosulfonyl)imide, includes adding a water removal agent to a pretreatment liquid containing the crude lithium bis(fluorosulfonyl)imide to perform a dehydration reaction at a temperature ranging from 20? ? C. to 40? C., reacting the same for an additional 1 h to 6 h after an acid gas stops escaping from the reaction system, and filtering the reaction system to obtain a filtrate; the water removal agent is bismuth trichloride or antimony trichloride. Evaporating and concentrating the filtrate, and recrystallizing the concentrated filtrate are performed to obtain a purified lithium bis(fluorosulfonyl)imide.

A method of purifying a crude lithium bis(fluorosulfonyl)imide, includes adding a water removal agent to a pretreatment liquid containing the crude lithium bis(fluorosulfonyl)imide to perform a dehydration reaction at a temperature ranging from 20? ? C. to 40? C., reacting the same for an additional 1 h to 6 h after an acid gas stops escaping from the reaction system, and filtering the reaction system to obtain a filtrate; the water removal agent is bismuth trichloride or antimony trichloride. Evaporating and concentrating the filtrate, and recrystallizing the concentrated filtrate are performed to obtain a purified lithium bis(fluorosulfonyl)imide.

The invention relates to a method for preparing bis(fluorosulfonyl)imide acid, comprising: the reaction of sulphamic acid or one of the salts thereof with a halogenosulfuric acid and at least one fluorinating agent selected from SOF.sub.2, FSO.sub.2F and SF.sub.4, and the subsequent recovery of bis(fluorosulfonyl)imide acid. The invention also relates to a method for producing salts of bis(fluorosulfonyl)imide from the bis(fluorosulfonyl)imide acid thus produced.

The invention relates to a method for preparing bis(fluorosulfonyl)imide acid, comprising: the reaction of sulphamic acid or one of the salts thereof with a halogenosulfuric acid and at least one fluorinating agent selected from SOF.sub.2, FSO.sub.2F and SF.sub.4, and the subsequent recovery of bis(fluorosulfonyl)imide acid. The invention also relates to a method for producing salts of bis(fluorosulfonyl)imide from the bis(fluorosulfonyl)imide acid thus produced.

The present invention provides a process for producing hydrogen bis(fluorosulfonyl)-imide (HFSI) by fluorination of a liquid hydrogen bis(chlorosulfonyl)imide (HCSI) using a gaseous hydrogen fluoride. In some embodiments, HFSI that is produced is separated from the reaction mixture as a gas and is condensed to collect a liquid HFSI.

The present invention provides a process for producing hydrogen bis(fluorosulfonyl)-imide (HFSI) by fluorination of a liquid hydrogen bis(chlorosulfonyl)imide (HCSI) using a gaseous hydrogen fluoride. In some embodiments, HFSI that is produced is separated from the reaction mixture as a gas and is condensed to collect a liquid HFSI.

The present invention relates to a bis(fluorosulfonyl)imide alkali metal salt (MFSI) having decomposition stability for lithium hexafluorophosphate (LiPF.sub.6) and a manufacturing method therefor.

A method of purifying a crude lithium bis(fluorosulfonyl)imide, includes adding a water removal agent to a pretreatment liquid containing the crude lithium bis(fluorosulfonyl)imide to perform a dehydration reaction at a temperature ranging from 20? C. to 40? C., reacting the same for an additional 1 h to 6 h after an acid gas stops escaping from the reaction system, and filtering the reaction system to obtain a filtrate; the water removal agent is bismuth trichloride or antimony trichloride. Evaporating and concentrating the filtrate, and recrystallizing the concentrated filtrate are performed to obtain a purified lithium bis(fluorosulfonyl)imide.

A method of purifying a crude lithium bis(fluorosulfonyl)imide, includes adding a water removal agent to a pretreatment liquid containing the crude lithium bis(fluorosulfonyl)imide to perform a dehydration reaction at a temperature ranging from 20? C. to 40? C., reacting the same for an additional 1 h to 6 h after an acid gas stops escaping from the reaction system, and filtering the reaction system to obtain a filtrate; the water removal agent is bismuth trichloride or antimony trichloride. Evaporating and concentrating the filtrate, and recrystallizing the concentrated filtrate are performed to obtain a purified lithium bis(fluorosulfonyl)imide.