Study Of Electrical Conductivity Of Solid Polymer Electrolytes For Electrochemical Storage Device Applications

Abstract

The growing demand for safe, efficient, and sustainable energy storage has accelerated research into solid polymer electrolytes (SPEs) as alternatives to conventional liquid electrolytes in solid-state batteries (SSBs). Polymer electrolytes combine mechanical flexibility, lightweight design, and enhanced safety, while their performance critically depends on the choice of polymer matrix, salt type, and the interplay between structural and electrical properties. The present thesis focuses on blend polymer electrolytes based on fluorinated and non-fluorinated polymer systems incorporated with lithium and sodium salts, aiming to establish composition structure property correlations that govern ionic conduction and relaxation behaviour. newlineIn the first part, in Chapter 3, PVDF-HFP/PVP blend electrolytes doped with lithium iodide (LiI) were synthesized and characterized. Structural analysis revealed a significant reduction in crystallinity with increasing salt content, while FTIR confirmed Liand#8314; complexation with electron-rich polymer moieties. Impedance and dielectric analyses demonstrated non-Debye relaxation, with 15 wt.% LiI yielding the optimum ionic conductivity of 7.50 × 10and#8315;and#8309; S·cmand#8315;¹ at room temperature. Temperature-dependent studies confirmed Arrhenius-type behaviour, with conduction dominated by thermally activated hopping of Liand#8314; ions within amorphous domains. newline