Preparation and conductivity of the composite polymer electrolytes based on poly[bis(methoxyethoxyethoxy)phosphazene], LiClO4 and α-Al2O3

The preparation and ionic conductivity of a new class of ionic conducting composite polymer electrolytes (CPEs), poly(methoxyethoxyethoxy)phosphazene (MEEP)/lithium perchlorate (LiClO4)/α-Al2O3, formed by dispersing α-Al2O3 particles into MEEP/lithium perchlorate electrolytes are reported and discussed. The addition of α-Al2O3 leads to an enhancement of the conductivity in the composite polymer electrolytes prepared. The best conductivity obtained from the composite polymer electrolyte with 2.5 wt.% α-Al2O3 and 0.2 LiClO4 per polyphosphazene repeat unit is close to 10−4 S cm−1 at room temperature, which is the highest reported for the MEEP-based electrolytes. From the results of FTIR spectroscopy, DSC measurement, cation transport number and the temperature dependence of conductivity, an ion transport mechanism in the composite polymer electrolytes is proposed.