EFFECTS OF THERMAL HISTORY AND AGING ON PHASE-RELATIONSHIPS IN PB(CF3SO3)(2)-PEO ELECTROLYTES

The effect of ageing on the multiphase Pb(CF3SO3)(2)PEO(n) system has been studied with NMR, DSC and X-ray diffraction. At room temperature, fresh samples with n>11 contain crystalline PEO and an amorphous salt -polymer complex. The relative amount of the crystalline phase increas es with decreasing salt concentration and the actual salt concentratio n in the amorphous phase shows an approximately linear dependence on t he nominal salt concentration in the samples. After ageing, the initia lly amorphous salt complex is transformed to a crystalline complex for samples with n>9. In addition to the complex, the samples contain cry stalline PEG. The stoichiometry of this complex is different from the previously known crystalline complexes in this system with n=5 and 7.