A method of producing purified bis(fluorosulfonyl) imide includes providing a liquid mixture including bis(fluorosulfonyl) imide and fluorosulfonic acid and then contacting the liquid mixture with gaseous ammonia. The gaseous ammonia reacts with the fluorosulfonic acid to produce ammonium fluorosulfate. The method further includes separating the liquid mixture from the ammonium fluorosulfate.

A method for drying and purifying a lithium bis(fluorosulfonyl)imide salt in solution in an organic solvent S1, the method including the following steps: a) adding deionised water to dissolve and extract the lithium bis(fluorosulfonyl)imide salt, forming an aqueous solution of the salt; b) extracting the lithium bis(fluorosulfonyl)imide salt from the aqueous solution, using an organic solvent S2, the step being repeated at least once; c) concentrating the lithium bis(fluorosulfonyl)imide salt by evaporating the organic solvent S2 and the water, in a short-path thin-film evaporator, under the following conditions: temperature of 30° C. to 95° C., pressure of 10.sup.−3 mbar abs to 5 mbar abs, residence time no longer than 15 min; and d) optionally crystallising the lithium bis(fluorosulfonyl)imide salt. Also, a composition made of lithium bis(fluorosulfonyl)imide salt, and the uses thereof in Li-ion batteries.

The present invention relates to a method for drying and purifying a lithium bis(fluorosulfonyl)imide salt in solution in an organic solvent S1, said method comprising the following steps: a) adding deionised water to dissolve and extract the lithium bis(fluorosulfonyl)imide salt, forming an aqueous solution of said salt; b) extracting the lithium bis(fluorosulfonyl)imide salt from said aqueous solution, using an organic solvent S2, said step being repeated at least once; c) concentrating the lithium bis(fluorosulfonyl)imide salt by evaporating said organic solvent S2 and the water, in a short-path thin-film evaporator, under the following conditions: temperature of 30° C. to 95° C., pressure of 10.sup.−3 mbar abs to 5 mbar abs, residence time no longer than 15 min; and d) optionally crystallising the lithium bis(fluorosulfonyl)imide salt. The present invention likewise relates to a composition made of lithium bis(fluorosulfonyl)imide salt, and the uses thereof in Li-ion batteries.

A process for producing bis(fluorosulfonyl) imide includes providing a solution comprising fluorosulfonic acid and urea, the solution maintained at a solution temperature from about 0° C. to about 70° C.; reacting the solution in the presence of a reaction medium at a reaction temperature from 80° C. to about 170° C. to produce a product stream including bis(fluorosulfonyl) imide, ammonium fluorosulfate and the reaction medium; separating the ammonium fluorosulfate from the product stream to produce an intermediate product stream; and separating the intermediate product stream into a concentrated product stream and a first recycle stream, the concentrated product stream including a higher concentration of bis(fluorosulfonyl) imide than the first recycle stream.

A process for producing bis(fluorosulfonyl) imide includes providing a solution comprising fluorosulfonic acid and urea, the solution maintained at a solution temperature from about 0° C. to about 70° C.; reacting the solution in the presence of a reaction medium at a reaction temperature from 80° C. to about 170° C. to produce a product stream including bis(fluorosulfonyl) imide, ammonium fluorosulfate and the reaction medium; separating the ammonium fluorosulfate from the product stream to produce an intermediate product stream; and separating the intermediate product stream into a concentrated product stream and a first recycle stream, the concentrated product stream including a higher concentration of bis(fluorosulfonyl) imide than the first recycle stream.

A method for preparing Cl—SO.sub.2NHSO.sub.2Cl including a step of chlorinating sulphamic acid with at least one chlorinating agent and at least one sulphur-containing agent, the method resulting in a flow F1, preferably liquid, including Cl—SO.sub.2NHSO.sub.2Cl and a gas stream F2 including HCl and SO.sub.2, the method including a step a) of treating the gas stream F2. Also, a method for preparing LiFSI including the abovementioned method for preparing Cl—SO.sub.2NHSO.sub.2Cl.

A method for preparing Cl—SO.sub.2NHSO.sub.2Cl including a step of chlorinating sulphamic acid with at least one chlorinating agent and at least one sulphur-containing agent, the method resulting in a flow F1, preferably liquid, including Cl—SO.sub.2NHSO.sub.2Cl and a gas stream F2 including HCl and SO.sub.2, the method including a step a) of treating the gas stream F2. Also, a method for preparing LiFSI including the abovementioned method for preparing Cl—SO.sub.2NHSO.sub.2Cl.

The invention relates to a new process for the synthesis of fluorinated conductive salts for lithium ion batteries (Li-ion batteries). The said fluorinated conductive lithium ion (Li-ion) battery salts of interest in the framework of the present inventions synthesis process, for example, are Li-ion salts such as LiFSI (lithium bis-(fluoromethanesulfonlyl) imide), LiTFSI (lithium bis-(trifluormethanesulfonlyl) imide), and LiTFSFI (lithium trifluoromethanesulfonylfluorosulfonyl imide), with the formulas as displayed in the Table I herein below. LiFSI, LiTFSI and LiFSTFSI are the most promising conducting salts for Lithium ion batteries and essential for future electromobility.

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 method for preparing a compound having the following formula (IV): R.sub.2(SO.sub.2)NLi(SO.sub.2)F (IV), the method including a step a) of reacting a sulphamide having the following formula (A): R.sub.0(SO.sub.2)NH.sub.2 (A) with at least one sulphur-containing acid and at least one chlorinating agent, the step a) being carried out: at a temperature between 90 C. and 130 C., and at a pressure which is strictly greater than 7 bar (absolute).