The characteristics and the performance of a rechargeable battery using PEO‐based polymeric electrolytes, have been examined at 100°C by potential‐composition curves, cyclic voltammetry, and cycling tests. The results indicate that the electrochemical process, which involves the intercalation of lithium in the vanadium bronze may be reversibly extended up to levels of equal to 3. Prolonged cycling with good capacity retention have been obtained using both and electrolytes.