CHARGE AND DISCHARGE CHARACTERISTICS OF LITHIUM-ION GRAPHITE-ELECTRODES IN SOLID-STATE CELLS

Lithium ions have been electrochemically intercalated into graphite in solid-state cells operating with solid polymer electrolytes based on poly(ethylene oxide) (PEG) complexed with lithium perchlorate (LiClO4) . The working composite electrode is composed of active-divided natura l graphite associated with P(EO)(8)-LiClO4 acting as a binder and a Li + ionic conductor. Intercalation and de-intercalation of Li+ were perf ormed using galvanostatic or voltammetry techniques. The curves obtain ed in our solid-state cells were compared with those performed in liqu id ethylene carbonate-LiClO4 electrolyte. It is shown that in solid-st ate cells, side reactions occur both in the reduction and in the oxida tion processes which leads to some uncertainty in the determination of the maximum reversible capacity of the graphite material.