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 composition containing: at least 99.75% by weight of bis(fluorosulfonyl)imide lithium salt. A process for preparing the composition, including a) step of preconcentrating a composition C1 including an organic solvent OS1, water and bis(fluorosulfonyl)imide salt, to give a composition C2 including: the lithium salt of bis(fluorosulfonyl)imide in a content ranging from 35% to 50% relative to the total weight of composition C2; water in a mass content of less than or equal to 500 ppm relative to the total mass of composition C2; the preconcentration step being performed at a temperature of less than or equal to 50° C.; b) a step of concentrating composition C2; c) an optional step of crystallizing the composition obtained in step b).

The present invention relates to a method for purifying a salt of bis (fluorosulfonyl) imide which is economically feasible at industrial scale and provides a high-purity product. Said method comprises the steps of providing a crude salt of bis (fluorosulfonyl) imide, dissolving the crude salt of bis (fluorosulfonyl) imide in at least one first solvent, crystallizing the salt of bis (fluorsulfonyl) imide by means of at least one second solvent and separating the crystallized salt of bis (fluorsulfonyl) imide, which can optionally be further reacted with an alkali salt, to obtain an alkali salt of bis (fluorosulfonyl) imide.

The present invention relates to a method for purifying a salt of bis (fluorosulfonyl) imide which is economically feasible at industrial scale and provides a high-purity product. Said method comprises the steps of providing a crude salt of bis (fluorosulfonyl) imide, dissolving the crude salt of bis (fluorosulfonyl) imide in at least one first solvent, crystallizing the salt of bis (fluorsulfonyl) imide by means of at least one second solvent and separating the crystallized salt of bis (fluorsulfonyl) imide, which can optionally be further reacted with an alkali salt, to obtain an alkali salt of bis (fluorosulfonyl) imide.

A method for preparing lithium bis(fluorosulfonyl)imide, including (1) adding an organic solvent and an absorbent A to a reaction kettle, then adding part of an ammonia source, and finally adding SO.sub.2X.sub.2 and a remaining ammonia source simultaneously for reaction, to obtain a solution of a salt (SO.sub.2F—NH—SO.sub.2F).Math.A containing bis(fluorosulfonyl)imide and the absorbent A, where in the SO.sub.2X.sub.2, X is independently fluorine or chlorine; (2) performing filtration, concentration and washing on the solution obtained in step (1) to obtain a purified salt (SO.sub.2F—NH—SO.sub.2F).Math.A of the bis(fluorosulfonyl)imide and the absorbent A; (3) adding a lithium source to the purified salt (SO.sub.2F—NH—SO.sub.2F).Math.A of the bis(fluorosulfonyl)imide and the absorbent A obtained in step (2) for reaction to obtain a solution containing lithium bis(fluorosulfonyl)imide; and (4) performing dehydration, concentration, crystallization with a non-aqueous poor solvent, and drying on the solution obtained in step (3) to obtain the lithium bis(fluorosulfonyl)imide is described.

A method for preparing lithium bis(fluorosulfonyl)imide, including (1) adding an organic solvent and an absorbent A to a reaction kettle, then adding part of an ammonia source, and finally adding SO.sub.2X.sub.2 and a remaining ammonia source simultaneously for reaction, to obtain a solution of a salt (SO.sub.2F—NH—SO.sub.2F).Math.A containing bis(fluorosulfonyl)imide and the absorbent A, where in the SO.sub.2X.sub.2, X is independently fluorine or chlorine; (2) performing filtration, concentration and washing on the solution obtained in step (1) to obtain a purified salt (SO.sub.2F—NH—SO.sub.2F).Math.A of the bis(fluorosulfonyl)imide and the absorbent A; (3) adding a lithium source to the purified salt (SO.sub.2F—NH—SO.sub.2F).Math.A of the bis(fluorosulfonyl)imide and the absorbent A obtained in step (2) for reaction to obtain a solution containing lithium bis(fluorosulfonyl)imide; and (4) performing dehydration, concentration, crystallization with a non-aqueous poor solvent, and drying on the solution obtained in step (3) to obtain the lithium bis(fluorosulfonyl)imide is described.

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.

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 a process for preparing a compound having the following formula (II):

F—SO.sub.2—N.sup.−—SO.sub.2—R.sub.1NH.sub.4.sup.+  (II)

wherein R.sub.1 represents F or a linear or branched alkyl radical, substituted with at least one fluorine atom, said process comprising a step of bringing an anhydrous flow F1 comprising ammonia (NH.sub.3) into contact with a compound of formula (I):

F—SO.sub.2—NH—SO.sub.2—R.sub.1  (I)

R.sub.1 is as defined above.