Dielectric Modulus and Conductivity Scaling Approach to the Analysis of Ion Transport in Solid Polymer Electrolytes

Abstract

Solid polymer electrolyte films (SPEs) based on poly(methyl methacrylate) are prepared using a solution cast technique. The temperature‐dependent behavior of dielectric, modulus spectra and ac conductivity has been investigated. The long tail of the real part of modulus (M′) in the low frequency indicates the capacitive nature of the samples. The frequency dependence of imaginary part of modulus (M″) shows a non‐Debye relaxation that has been explained using the Kohlrausch–Williams–Watts stretched exponential function. The activation energy for the relaxation is almost same as the activation energy for the conduction. The relaxation time obtained from the tangent loss graph (τδ) is about two orders of magnitude larger than that obtained from the imaginary part of modulus graph (τm). The ac conductivity has been found to obey Jonscher's universal power law. Transport parameters show that addition of filler creates additional hopping sites for the charge carriers and also increases the charge carrier density. It is also observed that the higher ionic conductivity at higher temperature is due to increased thermally activated hopping rates accompanied by a significant increase in carrier concentration. The contribution of carrier concentration to the total conductivity is also confirmed from Summerfield scaling. POLYM. ENG. SCI., 60: 297–305, 2019. © 2019 Society of Plastics Engineers