Boosting reversible charging of Li-ion batteries at low temperatures by a synergy of propylene carbonate-based electrolyte and defective graphite.

Propylene carbonate (PC)-based electrolytes have exhibited significant advantages in boosting the low-temperature discharging of graphite-based Li-ion batteries. However, it is still unclear whether they can improve the charging property and suppress lithium plating. Studying this topic is challenging due to the problem of electrochemical compatibility. To overcome this issue, we introduced graphite with phase defects. The results show that the pouch-type full batteries using PC-based electrolyte exhibit steady performance over 500 cycles and can be reversibly charged over 30 times at −20 °C with an average Coulombic efficiency of 99.95%, while the corresponding value for the conventional ethylene carbonate (EC)-based electrolyte sample is only 31.20%. This indicates that the use of PC-based electrolyte significantly suppresses lithium plating during low-temperature charging. We further demonstrate that the improved performance is mainly attributed to the unique solvation structure, where more PF 6 − anions participate in solvation, leading to the formation of a stable F-rich solid state electrolyte interface on the graphite surface and a lower reduction tendency of Li⁺ ions. This work inspires new ideas for the design of PC-based electrolytes for low-temperature charging and fast-charging batteries. [ABSTRACT FROM AUTHOR]