Thermal history — conductivity relationship in lithium salt-poly (ethylene oxide) complex polymer electrolytes

A.C. conductivity measurements on a number of lithium salt-poly(ethylene oxide) (PEO) complex polymer electrolytes have been correlated with the results of D.S.C. analysis. An enhancement in the conductivity of compositions with O:Li ratios of greater than 6:1 on annealing at above 150°C was attributed to the melting of the polymer crystalline phase and the retention of an amorphous polymer structure in the electrolyte on cooling down to the crystallisation temperature of the pure PEO phase.