A method for efficiently removing impurities such as sodium ions, fluoride ions, chloride ions and fluorosulfate ions without reducing the yield of a target product, including a fluorine-containing sulfonylamide compound selected from the group consisting of fluorine-containing sulfonylamide, a metal salt thereof, an ammonium salt thereof and a quaternary ammonium salt thereof is washed with an aqueous solution of salt of sulfuric acid.

A method for efficiently removing impurities such as sodium ions, fluoride ions, chloride ions and fluorosulfate ions without reducing the yield of a target product, including a fluorine-containing sulfonylamide compound selected from the group consisting of fluorine-containing sulfonylamide, a metal salt thereof, an ammonium salt thereof and a quaternary ammonium salt thereof is washed with an aqueous solution of salt of sulfuric 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 3,4-dicyano-2-trifluoromethylimidazole (TDI). The methods comprise contacting 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 3,4-dicyano-2-trifluoromethylimidazole (TDI). The methods comprise contacting TDI with an alkaline earth metal bis(trifluoroacetate) salt in trifluoroacetic acid.

Methods of removing target impurities from a crude lithium bis(fluorosulfonyl)imide (LiFSI) to make a purified LiFSI product. In some embodiments, a purification method includes contacting crude LiFSI with a first anhydrous organic solvent to create a solution containing LiFSI and the target impurity(ies), wherein the LiFSI is soluble and the impurity(ies) is/are substantially insoluble. In some embodiments, a second anhydrous organic solvent is added to the solution to precipitate the target impurity(ies), which is then filtered to obtain a filtrate. In some embodiments, solvent is removed from the filtrate to obtain a solid mass containing LiFSI, which may then be contacted with a third anhydrous organic solvent in which the LiFSI is insoluble. The LiFSI may then be isolated from the third anhydrous organic solvent to obtain the purified LiFSI product. Also disclosed are purified LiFSI products and electrochemical devices utilizing purified LiFSI products, among other things.

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 recovering raw and auxiliary materials in the production of lithium bis(fluorosulfonyl)imide is described. The method includes one or more different recovery sections A, B, C, D and/or E, corresponding to the recovery and post-treatment of the raw and auxiliary materials such as triethylamine, a fluoride ion, an ester solvent, and a crystallization liquid respectively used in the production of lithium bis(fluorosulfonyl)imide. The method for recovering raw and auxiliary materials of the present application enables the production of lithium bis(fluorosulfonyl)imide to have significantly improved economic efficiency and environmental protection.

A method for recovering raw and auxiliary materials in the production of lithium bis(fluorosulfonyl)imide is described. The method includes one or more different recovery sections A, B, C, D and/or E, corresponding to the recovery and post-treatment of the raw and auxiliary materials such as triethylamine, a fluoride ion, an ester solvent, and a crystallization liquid respectively used in the production of lithium bis(fluorosulfonyl)imide. The method for recovering raw and auxiliary materials of the present application enables the production of lithium bis(fluorosulfonyl)imide to have significantly improved economic efficiency and environmental protection.

A lithium bis(fluorosulfonyl)imide salt, wherein, after dissolving in water to form an aqueous solution, the aqueous solution has a pH of between 4 and 8, in particular at a temperature of 25 C., and the uses thereof in Li-ion batteries. Also, a lithium bis(fluorosulfonyl)imide salt, including a content of H+ ions of between 0.08 ppb and 0.80 ppm, between 0.08 ppb and 0.63 ppm or between 0.25 ppb and 2.53 ppb.