How Ethyl Methyl Carbonate Assists Ethylene Carbonate in Co-Intercalating into Graphite Electrode with PF6−

Solvent dramatically affects the behavior of anion intercalation into graphite electrode in dual-ion batteries (DIBs). Our previous studies have confirmed that the intercalation of ethylene carbonate (EC) solvated PF6− is considerably suppressed. However, in this letter, we show that EC can apparently co-intercalate with PF6− into graphite electrode once ethyl methyl carbonate (EMC) is involved inside. In situ X-ray diffraction (in situ XRD), ex situ XRD, fourier transform infrared (FTIR) spectroscopy and electrochemical impedance spectroscopy (EIS) have been carried out to clarify the underlying reason.