IONIC-CONDUCTION IN COMPOSITE POLYMER ELECTROLYTES AT SUBAMBIENT TEMPERATURES

The majority of investigations carried out. on polymer-salt systems ha ve been on polyether electrolytes at moderate temperatures where such electrolytes exhibit macroscopic uniformity. Relatively little attenti on has been paid to the subambient temperature region where composite electrolytes based on polyethers exhibit much higher conductivities th an their pure polyether electrolyte analogues. For all of the composit e systems studied the conduction mechanism changes from one in which t he ions are coupled to the polymer segmental relaxations to one in whi ch the ions are decoupled and thermally activated ionic hopping produc es higher conductivities than would be expected from ion-segmental cou pling and higher than observed for the base polyether-salt system. Thi s change has been observed at temperatures between 10 and 80 degrees C above the respective glass transition temperatures. The relationship between this interaction and these higher conductivities at subambient temperatures is explored and discussed. (C) 1996 John Wiley & Sons, I nc.