Stabilization of Lithium Bis(fluorosulfonyl)imide Electrolyte by the Incorporation of Pyridinium Ionic Liquids for Advanced Lithium‐Ion Batteries

Highly efficient lithium‐ion batteries (LIBs) with lithium bis(fluorosulfonyl)imide (LiFSI) electrolytes have been explored over LiFP 6 electrolytes owing to their fabulous ionic conductivity, good thermal stability, and HF‐free nature. This work investigates the influence of ionic liquid (IL), 1‐propyl‐2‐methylpyridium bis(trifluoromethylsulfony)imide ([Pyr 3 ‐ 2 Me][(CF 3 SO 2 ) 2 N], Pyr 32 TFSI) as an additive in LiFSI electrolyte on the electrical, electrochemical, and flammability properties of LIBs. The addition of Pyr 32 TFSI additive has considerably elevated the ionic conductivity and thermal stability of LiFSI electrolytes. Pyr 32 TFSI IL modified LiFSI electrolyte exhibits an increased ionic conductivity from 16.4 mS·cm −1 (LiFSI electrolyte) to 17.3 mS·cm −1 . With Pyr 32 TFSI additive, the lithium transfer number () has increased, which is usually associated with the synergistic effect of the additive to LiFSI and builds an inorganic “LiF”‐rich dendrite‐free interphase. The flammability test of Pyr 32 TFSI IL modified LiFSI electrolyte explicates the nonflammable nature, indicating excellent stability in ambient and extreme circumstances. Fabricated graphite|Li half‐cell LIBs with Pyr 32 TFSI IL modified LiFSI electrolytes, display the improved performance in charging/discharging ability with a capacity of 380 mAh·g −1 , exhibiting marvelous cycling stability up to 200 cycles. Our work shows that incorporating LiFSI with novel ILs could be a promising approach for manufacturing high‐performance liquid electrolytes for LIBs.