RESPONSE OF CONDUCTIVITY TOWARDS THE CONCENTRATION OF LITHIUM PERCHLORATE SALT IN SOLID POLYMER ELECTROLYTES

Abstract

The polymer blend electrolytes composed of a fixed ratio of poly (ethylmethacrylate) (PEMA) and Poly (vinyl acetate) (PVAc) and various concentrations of lithium
perchlorate (LiClO4) are synthesized by solvent casting technique. AC impedance analysis is carried out to investigate the ionic conductivity of the prepared samples. The maximum ionic conductivity of 3.541 × 10- 5 Scm - 1 at 303K is obtained for PEMA/PVAc (70/30wt%)– LiClO4(8wt%) polymer blend electrolyte system. The XRD and FTIR techniques are adopted to confirm the polymer-salt complexation. The porosity in SEM micrographs is in line with the conductivity measurements. The Glass Transition temperature (Tg) of the blend polymer electrolytes is estimated from DSC measurements and the Tg values agree with the
conductivity results. The Linear sweep voltammetry (LSV) analysis is carried out on the polymer electrolyte film of maximum ionic conductivity and shows that the operational potential window of the electrolyte membrane is from -0.8 to +2.8V. The Cyclic voltammetry (CV) is employed to evaluate the electrochemical stability of the polymer electrolyte membrane with 8 wt% of LiClO4. The Lithium transference number measurements are carried out by chronoamperometry technique which reveals that the ion transport is predominant in the prepared sample.