Ionic conductivity of polymer-ceramic composites

The paper analyzes ionic conductivity data in the PEO:LiBF4-MgO and PEO:LiB F4-BaTiO3 composite electrolyte systems. The polymer and ceramic phases in the systems interact to provide a stable, amorphous phase. The ceramic phas e is believed to impart a dual effect. It suppresses crystallization of and interacts with the polymer phase. The nature of the interaction is believe d to be dipole-dipole and driven by a dielectric constant gradient. The nan osize ceramic powder provides higher conductivity values because of an enha nced interaction. At low temperatures (similar or equal to 20 degreesC) the dipole-dipole interaction is favored, whereas at high temperatures (simila r or equal to 100 degreesC) a reverse trend is observed. A very high dielec tric constant material such as BaTiO3 provides little additional benefit. ( C) 2001 The Electrochemical Society.