Design of cyclic carbonate-based electrolytes for HC anodes towards improved low-temperature performance in lithium-ion batteries system

Hard carbon (HC) anodes for lithium-ion batteries (LIBs) have become more promising anode materials due to their high capacity, excellent capacity retention, superior cycling stability, low operating potential and mild electrode expansion. However, the compatibility of commonly used carbonate-based electrolytes in HC anode systems has rarely been investigated. Here, we systematically investigate the effects of the two most commonly used major components in electrolyte systems, ethylene carbonate and propylene carbonate, on the HC anode of LIBs, including the cycling performance, Li + transport kinetics, and electrolyte–electrode interface composition. The results show that the propylene carbonate system possesses better cycling stability and kinetics in HC anodes for LIBs. Especially at low temperatures, the propylene carbonate system exhibited high-capacity retention (57.7 % at −20 °C and 24.1 % at −40 °C). Mechanistic studies reveal that Li + possess lower solvation energy in propylene carbonate, which can be easily separated from the solution to participate with the charging and discharging process. Moreover, due to the lower freezing point of propylene carbonate (−48.8 °C), PC-electrolyte based LIBs deliver good low temperature cycling stability. This work will provide guidance for the selection and design of HC anodes and electrolytes for LIBs in the near future.