Influence of Blend on the Conductivity in Poly(Ethyl Methacrylate)/Poly(Vinyl Acetate) Based Polymer Electrolytes

Abstract

The polymer blend electrolytes composed of poly (ethyl methacrylate)(PEMA) and Poly (vinyl acetate)(PVAc) as host polymer and lithium perchlorate (LiClO4) as a salt are synthesized by solvent casting technique. The polymer membranes with different wt% of PEMA and PVAc are subjected to AC impedance analysis for the investigation of ionic conductivity. The maximum ionic conductivity of 3.541 X 10- 5Scm- 1 at 303K is reported for PEMA/PVAC (70/30wt%) –LiClO4 (8wt%) polymer blend electrolyte system.The complexation has been confirmed by XRD and FTIR techniques. The glass transition temperature (Tg) of the blend polymer electrolytes has been obtained from DSC measurements. The SEM micrographs show the surface morphology of the prepared samples. The electrochemical stability of the sample exhibiting high conductivity has been carried out using linear sweep voltammetry (LSV) and cyclic voltammetry (CV) measurements. The potential window has been found to be-2.5 to +2.5 V. The lithium transference number evaluated using chronoamperometry technique results in a value of 0.90. The dielectric behavior of the solid polymer blend electrolytes has been analyzed as a function of frequency and temperature. The dc conductivity values obtained from the conductance spectra match the ac impedance results. The photoluminescence spectra that contain information about the local free volume of the prepared samples justify the conductivity results. The two and three dimensional images of the maximum ionic conducting sample exhibit numerous micropores.