A composition containing: at least 99.75% by weight of bis(fluorosulfonyl)imide lithium salt; and acetic acid in a content by mass greater than 0 and less than or equal to 400 ppm. 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; said 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).

In the present invention, a bis (fluorosulfonyl) imide metal salt is an alkali metal salt of bis (fluorosulfonyl) imide or an alkaline earth metal salt of bis (fluorosulfonyl) imide. The bis (fluorosulfonyl) imide metal salt has an average particle diameter of not less than 0.1 mm, or has an average moisture absorption rate of not more than 2.5 mass ppm/cm.sup.2.Math.min when sealed in a PE bag having a thickness of 80 μm and left for 30 minutes at 23° C. and 65% humidity.

In the present invention, a bis (fluorosulfonyl) imide metal salt is an alkali metal salt of bis (fluorosulfonyl) imide or an alkaline earth metal salt of bis (fluorosulfonyl) imide. The bis (fluorosulfonyl) imide metal salt has an average particle diameter of not less than 0.1 mm, or has an average moisture absorption rate of not more than 2.5 mass ppm/cm.sup.2.Math.min when sealed in a PE bag having a thickness of 80 μm and left for 30 minutes at 23° C. and 65% humidity.

A method to make heteroatom doped polymer nanosphere/carbon nanospheres uses aromatic amine and aldehyde as raw materials, and in the presence of a compound represented by formula I, reacts the aldehyde with the compound represented by formula Ito form a Schiff base, and then reacts the aromatic amine with the resulting Schiff base, wherein the reaction is conducted in an aqueous solution system at a mild reaction temperature (10° C. to 50° C.) under stirring. The resulting polymer nanospheres are subject to centrifugation and drying, followed by roasting in an inert atmosphere to obtain carbon nanospheres. The nanospheres product prepared using the method has controllable dimensions and morphology, an even particle size, and homogeneously doped heteroatoms.

A method for producing a lithium bis(fluorosulfonyl)imide salt F—(SO.sub.2)—NLi—(SO.sub.2)—F, comprising a step comprising a step of chlorination of sulfamic acid HO—(SO.sub.2)—NH.sub.2 in order to obtain the bis(chlorosulfonyl)imide Cl—(SO.sub.2)—NH—(SO.sub.2)—Cl, said step being carried out in a reactor made of a corrosion-resistant material M3, or in a reactor containing a base layer made of a material M1 coated with a surface layer made of a corrosion-resistant material M2.

A method for producing a lithium bis(fluorosulfonyl)imide salt F—(SO.sub.2)—NLi—(SO.sub.2)—F, comprising a step comprising a step of chlorination of sulfamic acid HO—(SO.sub.2)—NH.sub.2 in order to obtain the bis(chlorosulfonyl)imide Cl—(SO.sub.2)—NH—(SO.sub.2)—Cl, said step being carried out in a reactor made of a corrosion-resistant material M3, or in a reactor containing a base layer made of a material M1 coated with a surface layer made of a corrosion-resistant material M2.

Methods for making high-purity LiFSI salts and intermediate products using one, the other, or both of a reactive-solvent removal/replacement method and an LiFSI purification method. In some embodiments, the reactive-solvent removal/replacement method includes using non-reactive anhydrous organic solvents to remove and/or replace one or more reactive solvents in a crude LiFSI. In some embodiments, the LiFSI purification method includes using anhydrous organic solvents to remove impurities, such as synthesis impurities, from a crude LiFSI. In some embodiments, crude LiFSI can be made using an aqueous-based neutralization process. LiFSI salts and products made using methods of the disclosure are also described, as are uses of such salts and products and electrochemical devices that include such salts and products.

Methods for making high-purity LiFSI salts and intermediate products using one, the other, or both of a reactive-solvent removal/replacement method and an LiFSI purification method. In some embodiments, the reactive-solvent removal/replacement method includes using non-reactive anhydrous organic solvents to remove and/or replace one or more reactive solvents in a crude LiFSI. In some embodiments, the LiFSI purification method includes using anhydrous organic solvents to remove impurities, such as synthesis impurities, from a crude LiFSI. In some embodiments, crude LiFSI can be made using an aqueous-based neutralization process. LiFSI salts and products made using methods of the disclosure are also described, as are uses of such salts and products and electrochemical devices that include such salts and products.

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.

An object of the present invention is to provide a method for producing a bis(fluorosulfonyl)amide alkali metal salt powder having high purity while suppressing reduction in yield due to thermal decomposition, etc. The method for producing a bis(fluorosulfonyl)amide alkali metal salt powder according to the present invention comprises precipitating a bis(fluorosulfonyl)amide alkali metal salt by conducting distillation using a thin-film evaporator while adding a poor solvent for the bis(fluorosulfonyl)amide alkali metal salt such as an aromatic hydrocarbon solvent and a linear or branched aliphatic hydrocarbon solvent to a solution formed by dissolving the bis(fluorosulfonyl)amide alkali metal salt in a good solvent for the bis(fluorosulfonyl)amide alkali metal salt such as an ester solvent and nitrile solvent.