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.

A lithium bis(fluorosulfonyl)imide, a preparation method therefor and an application thereof, wherein iminodisulfonic acid is synthesized by using sulfur trioxide and ammonia as raw materials, the iminodisulfonic acid is chlorinated by means of thionyl chloride to obtain bis(chlorosulfonyl)imide, and then fluorination and lithiation are performed in sequence to obtain the lithium bis(fluorosulfonyl)imide. The method has excellent yield and purity; and compared with a traditional process, the method has the advantages of simple raw materials, less generation of three wastes, green environmental protection, fewer side reactions, low cost and the like, and is easy to industrialize.

A lithium bis(fluorosulfonyl)imide, a preparation method therefor and an application thereof, wherein iminodisulfonic acid is synthesized by using sulfur trioxide and ammonia as raw materials, the iminodisulfonic acid is chlorinated by means of thionyl chloride to obtain bis(chlorosulfonyl)imide, and then fluorination and lithiation are performed in sequence to obtain the lithium bis(fluorosulfonyl)imide. The method has excellent yield and purity; and compared with a traditional process, the method has the advantages of simple raw materials, less generation of three wastes, green environmental protection, fewer side reactions, low cost and the like, and is easy to industrialize.

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.

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.

Methods for preparing electrolyte salts for alkaline earth metal-ion batteries (e.g., calcium and magnesium ion batteries) are described. The electrolyte salts comprise alkaline earth metal (e.g., Mg or Ca) salts of bis(fluorosulfonyl)imide (FSI) and 3,4-dicyano-2-trifluoromethylimidazole (TDI). The methods comprise contacting FSI or TDI with an alkaline earth metal bis(trifluoroacetate) salt in trifluoroacetic acid.

Methods for preparing electrolyte salts for alkaline earth metal-ion batteries (e.g., calcium and magnesium ion batteries) are described. The electrolyte salts comprise alkaline earth metal (e.g., Mg or Ca) salts of bis(fluorosulfonyl)imide (FSI) and 3,4-dicyano-2-trifluoromethylimidazole (TDI). The methods comprise contacting FSI or TDI with an alkaline earth metal bis(trifluoroacetate) salt in trifluoroacetic acid.

The present invention provides an alkali metal salt of fluorosulfonyl imide having favorable heat resistance and a reduced content of specific impurities and a water content, and provides a method for producing an alkali metal salt of fluorosulfonyl imide, which is capable of easily removing a solvent from a reaction solution. An alkali metal salt of fluorosulfonyl imide of the present invention is represented by the following general formula (I) and has a mass loss rate of 2% or less when the alkali metal salt of fuluorosulufonyl imide is kept at 100 C. for 8 hours under an air current. A method for producing an alkali metal salt of fluorosulfonyl imide of the present invention comprises a step of concentrating a solution of the alkali metal salt of fulorosulfonyl imide by bubbling a gas into a reaction solution containing the alkali metal salt of fulorosulfonyl imide, and/or concentrating a solution of the alkali metal salt of fulorosulfonyl imide by thin layer distillation. ##STR00001##

The present invention provides an alkali metal salt of fluorosulfonyl imide having favorable heat resistance and a reduced content of specific impurities and a water content, and provides a method for producing an alkali metal salt of fluorosulfonyl imide, which is capable of easily removing a solvent from a reaction solution. An alkali metal salt of fluorosulfonyl imide of the present invention is represented by the following general formula (I) and has a mass loss rate of 2% or less when the alkali metal salt of fuluorosulufonyl imide is kept at 100 C. for 8 hours under an air current. A method for producing an alkali metal salt of fluorosulfonyl imide of the present invention comprises a step of concentrating a solution of the alkali metal salt of fulorosulfonyl imide by bubbling a gas into a reaction solution containing the alkali metal salt of fulorosulfonyl imide, and/or concentrating a solution of the alkali metal salt of fulorosulfonyl imide by thin layer distillation. ##STR00001##