Engineering solid electrolyte interphase for the application of propylene carbonate solvent for graphite anode in low temperate battery

Propylene carbonate (PC) is regarded as a good candidate solvent for low-temperature electrolyte applications due to its low melting point (−49.2 °C). However, the co-intercalation of PC into the graphite anode limits its use in low-temperature electrolytes. Along these lines, in this work, by pre-growing a stable solid electrolyte interphase (SEI) on the graphite anode in 1 M LiPF₆ FEC: DMC electrolyte, it was found that the co-intercalation of PC into graphite can be inhibited when the latter was cycled in 1 M LiDFOB EC: PC: DEC electrolyte. As was observed by in-situ Electrochemical atomic force microscopy (EC-AFM) measurements, the SEI film has a double-layer structure. Additionally, no gas generation was detected by differential electrochemical mass spectrometry (DEMS) during the cycling, demonstrating the stability of the SEI layer. The addition of PC improves the low-temperature performance of the battery, which can be charged and discharged at −20 °C, while the discharge capacity can reach about 75% of room temperature's discharge capacity. Our work provides a new idea for the design of low-temperature PC-based electrolytes for the next-generation battery systems.