Understanding the mechanism behind improved cycling stability of FeF3 cathode in lithium bis(fluorosulfonyl)amide-concentrated electrolytes†

We investigate the mechanism behind the improved discharge/charge cycling stability of FeF₃ cathode in lithium bis(fluorosulfonyl)amide (LiFSA)-concentrated electrolytes. Macroscopic and microscopic analyses reveal that the concentrated electrolyte effectively suppresses the formation of inactive Fe and LiF in the cycled FeF₃ at the charged state, thus improving the cycling stability.