LiFSI Method for producing bis fluorosulfonyl imide lithium salt LiFSI with reduced fluorine anion content

摘要

In the present invention, (a) bis(chlorosulfonyl)imide and NH ₄ F(HF)n (n=0~10) in a nitrogen atmosphere are diethyl ether, diisopropyl ether, methyl-t-butyl ether, acetic acid. Preparing ammonium bis(fluorosulfonyl)imide by reacting in one or more solvents selected from the group consisting of methyl, ethyl acetate, propyl acetate, and butyl acetate; (b) After the reaction in step (a) is terminated, the reaction product is cooled to 50 to 70°C, and then nitrogen gas is supplied to the reaction solution and bubbling is performed until the pH of the flying gas is 6 to 8. Step to do; (c) reacting the ammonium bis(fluorosulfonyl)imide obtained in step (b) with a lithium base to prepare a bis(fluorosulfonyl)imide lithium sa (d) introducing the bis(fluorosulfonyl)imide lithium salt and antisolvent prepared in step (c) into a reactor; (e) adding lithium methoxide or lithium methoxide solution to the reactor and stirring; And (f) filtering the solution stirred in step (e) and drying the filtrate; including, It provides a method for producing a bis(fluorosulfonyl)imide lithium salt, characterized in that the pH of the gas carried in step (b) is measured using a pH paper.