POLYMER ELECTROLYTE LITHIUM BATTERIES RECHARGEABILITY AND POSITIVE ELECTRODE DEGRADATION - AN AC IMPEDANCE STUDY

AC impedance measurements of polymer electrolyte-based, symmetrical composite cathode cells were used to probe the effects of the composite cathode composition and fabrication process upon its performance when used in polymer electrolyte-based thin film rechargeable lithium batteries. The relationship between cycling performance and AC impedance measurements were used to elucidate some of the reported failure mechanisms of rechargeable lithium polymer electrolyte batteries. The rapid initial capacity decay observed within the first few cycles of the polymer electrolyte/V6O13 based composite cathode is shown to be related to the properties of the composite cathode active material, while the slower capacity decay observed during subsequent cycles, under continuous cycling regimes, appears to be related to a loss of ionic and electronic contact in the composite cathode.