Metal bis(fluorosulfonyl)imide liquid salt and preparation method thereof

A method for preparing a metal bis(fluorosulfonyl)imide liquid salt, the method comprising:

• reacting bis(fluorosulfonyl)imide with a metal fluoride compound, to obtain a molten reaction solution, wherein the molten reaction solution is obtained by reacting the bis(fluorosulfonyl)imide with the metal fluoride compound under a solvent-free condition;
• and
• performing a devolatilization treatment on the reaction solution until an EP1 acidity, calculated as an equivalent amount of hydrofluoric acid, is less than or equal to 0.5 ppm, to obtain a bis(fluorosulfonyl)imide metal compound, and
• dissolving the bis(fluorosulfonyl)imide metal compound in a solvent, and performing a deacidification treatment using a resin on the bis(fluorosulfonyl)imide metal compound solution, to obtain the metal bis(fluorosulfonyl)imide liquid salt,
• wherein a vacuum pressure of the devolatilization treatment ranges from 1 kPa to 0.1 kPa, and a heating temperature of the devolatilization treatment ranges from 100°C to 140°C.