Fire‐Resistant Carboxylate‐Based Electrolyte for Safe and Wide‐Temperature Lithium‐Ion Batteries

Abstract The combustion accident and narrow temperature range of rechargeable lithium‐ion batteries (LIBs) limit its further expansion. Non‐flammable solvents with a wide liquid range hold the key to safer LIBs with a wide temperature adaptability. Herein, a carboxylate‐based weak interaction electrolyte is achieved by molecular design, which consists of EDFA (ethyl difluoroacetate), 1,1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropylether, and fluoroethylene carbonate. The inherent non‐flammable and wide liquid‐rang features of the electrolyte ensure the safety as well as the wide operating temperature of a battery. The high affinity between FSI − anions and counter Li + guarantees a stable and inorganic‐components‐dominated electrolyte/electrode interphase with rapid Li + de‐solvation kinetics, leading to perfect compatibility with graphite and avoiding side reactions between lithiated graphite and electrolyte. The rationally designed EDFA‐based electrolyte enables the thick graphite (4.4 mAh cm −2 ) || LiNi 0.8 Co 0.1 Mn 0.1 O 2 (4.0 mAh cm −2 ) cells to operate efficiently in a wide temperature range from −30 to 45 °C. The proposed EDFA‐based electrolyte enables the commercial 1.0 Ah graphite || NCA (LiNi 0.8 Co 0.15 Al 0.05 O 2 , >3.2 mAh cm −2 ) pouch cells stably cycle for >1100 cycles (>85% capacity retention) at 0.3C and >800 cycles at 1.0C (>92% capacity retention), while also endows the graphite/SiO x and Li anode‐based batteries with high energy density, long lifespan and high safety.