Polyphosphazene‐Poly(Olefin Oxide) Mixed Polymer Electrolytes: I . Conductivity and Thermal Studies of

Abstract

Mixed polymer electrolytes composed of Li salt complexes of poly[bis‐(methoxyethoxyethoxide)phosphazene], called MEEP, and poly(ethylene oxide), known as PEO, have shown excellent dimensional stability and high conductivity. mixed polymer electrolytes, in which , have exhibited conductivities at 60°C which are comparable to the conductivity of at 100°C. Furthermore, the conductivity of these mixed electrolytes at room temperature is about 500‐fold better than that of PEO‐based electrolytes. These will translate into higher rate capability and/or lower temperature of operation for solid‐state Li cells containing these mixed electrolytes. Complexes containing , , and exhibited lower conductivities than those containing and . The higher conductivity of the mixed electrolytes compared to PEO complexes may be attributed to the higher degree of amorphous character introduced by the presence of MEEP.