FEMC is widely used as a solvent or co-solvent in cutting-edge electrolyte formulations for next-generation lithium batteries. Its trifluoroethyl group promotes the formation of a stable, LiF-rich Solid Electrolyte Interphase (SEI) on graphite and silicon anodes, and effectively passivates high-voltage cathode surfaces. This function is crucial for increasing capacity retention, extending cycle life, and suppressing gas generation, making it indispensable for high-energy density and high-safety applications, including EVs and grid storage.