Electrochemical impedance spectroscopy study of C/Li2MnSiO4 composite cathode material at different states of charge

• EIS spectra of C/Li2MnSiO4 at different SOC were successfully obtained.
• Very good reversibility of Mn2 +/Mn3 + redox reaction was observed.
• Li2MnSiO4 amorphization entails increase of electronic and ionic conductivities.
• Initial charging provides formation of Li+ diffusion paths through the carbon coating.

C/Li2MnSiO4 nanocomposite material obtained by sol–gel synthesis was studied in initial charge/discharge cycle. Electrochemical impedance spectroscopy (EIS) analysis in different states of charge (SOC) allowed to describe changes in electrochemical properties of C/Li2MnSiO4. The activation process of carbon coating was analyzed and the stability of carbon coating confirmed. XPS measurement was used to prove range and reversibility of electrochemical charging/discharging process. Strong influence of Li2MnSiO4 amorphization on its electronic and ionic conductivity was observed.