LiF-Induced Stable Solid Electrolyte Interphase for a Wide Temperature SnO2-Based Anode Extensible to −50 °C

Lithium-ion batteries (LIBs) suffer dramatic energy reduction, and are even unable to safely charge below -10 °C, due to sluggish Li + transport kinetics in the anode, electrolyte and solid electrolyte interphase (SEI), as well as large overpotential which causes Li plating on the anode surface. Herein, a SnO 2 -LiF-graphite (SLG) composite anode is developed for wide temperature application. The SLG with a propylene carbonate electrolyte delivers a stable capacity of more than 900 mA h g −1 at 60 °C with 100 mA g −1 , maintaining 823.9 mA h g −1 at -10 °C. When matched with a tetrahydrofuran-based electrolyte, the SLG delivers stable capacities of 780.4 mA h g −1 at -40 °C and 637.2 mA h g −1 at -50 °C, respectively. It is demonstrated that the LiF-induced inorganic-rich SEI maintains the nanostructure of the active Sn, and that their interfaces with the electrolyte are highly stable. Furthermore, the formation of α-Sn with higher Li + diffusion kinetics results in a very small overpotential (≈0.18 V) of lithiation for SLG from 30 °C to -50 °C. This work shows that LiF-modified SnO 2 anodes matched with suitable electrolytes can qualify the LIBs for a safe and long-life at wide temperature, which is helpful to further promote these batteries for low-temperature applications.