Fire‐Resistant Carboxylate‐Based Electrolyte for Safe and Wide‐Temperature Lithium‐Ion Batteries
Yi Yang, Nan Yao, Yuxing Yao, Lei Xu, Xue‐Fei Wen, Zeheng Li, Z. Gary Yang, Chong Yan, Jia‐Qi Huang
Abstract
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.