Polyphosphazene‐Poly(Olefin Oxide) Mixed Polymer Electrolytes: II . Characterization of

The preparation, and conductivity, calorimetric, and electrochemical studies of mixed polymer electrolytes, where MEEP = poly[bis‐(methoxyethoxyethoxide)phosphazene], PPO = poly(propylene oxide) and , are described. The addition of PPO in various proportions to electrolytes significantly improved the latter's dimensional stability but caused a slight decrease in its conductivity. The conductivities of these mixed polymer electrolytes are much higher than that of . The Li + transport number in electrolytes, with , was determined to be between 0.3 and 0.5. Differential scanning calorimetric data established the predominantly amorphous nature of the mixed polymer complexes. Cyclic voltammetric studies of these electrolytes at a stainless steel electrode indicated a stability domain between 1 and 4.5V ( vs. Li + /Li), and established the good Li plating and stripping efficiency in these electrolytes.