A DESCRIPTION OF THE TEMPERATURE-DEPENDENCE OF THE CONDUCTIVITY FOR COMPOSITE POLYMERIC ELECTROLYTES BY EFFECTIVE-MEDIUM THEORY

The temperature dependence of the conductivity of composite polymeric electrolytes based on a poly (ethylene oxide) matrix is described by a model based on effective medium theory. The influence of grain size d istribution of the powder used as well as grain concentration on the c onductivity of the electrolytes studied is analyzed. It will be shown that increases in the concentration of inorganic fillers influence the conductivity of the interface layer covering the filler. This layer i s assumed to be responsible for an increase in the conductivity of com posite polymeric electrolytes in comparison to pristine poly (ethylene oxide)-based systems. Utilization of effective medium models to study the temperature dependence of the conductivity of composite electroly tes enables us to predict the applicability of the compensation law fo r studies of the entropy effect in the electrolytes studied. The chara cteristic order-disorder temperature found from calculations based on effective medium theory is equal to that experimentally found and corr esponds to the melting temperature of the crystalline polymer phase.