Interfacial phenomena on the graphite-lithium electrode during the formation process and thermal aging
Résumé
Slow scan voltammery (SSV), electrochemical impedance spectroscopy (EIS) and galvanostatic cycling (GC) were used to characterize the formation of the Solid Electrolyte Interphase (SEI) on a graphite electrode during lithiation and delithiation and during thermal aging. The SSV and GC results show the irreversible character of the first reduction peak/semi-plateau at 0.8 V. After aging, a new irreversible plateau appears in the GC curves. Concomitantly the interfacial resistances as determined from the Nyquist plots increased then decreased as the signature of SEI transformation. We suggest the SEI is subjected to precipitation/dissolution processes.