Influence of Lithium Sulfide Weight Ratio on Optical and Electrical Properties of Blend Solid Electrolytes Based on Chitosan/Polyvinylpyrrolidone

Abstract

The most popular electrochemical energy storage technology in the future will be solid-state lithium batteries, which have a high energy density, a small size, can work in a wide range of temperatures, and are easy to picaresque to produce biocompatible chitosan/polyvinylpyrrolidone (CS:PVP) polymer blends at a constant weight ratio of 50:50 with different lithium sulfide proportions. The synthesized samples were tested using FTIR, UV-visible, and alternating current conductivity. FTIR showed two peaks, confirming chitosan and PVP. Adding lithium and sulfide ions changed the polymer matrix hydrogen bonding network. The material's electrical structure changed when lithium sulfide content increased because UV-visible spectroscopy showed the optical bandgap narrowed. Lithium sulfide salt improved electronics, especially ionic conductivity. Highest ionic conductivity (2.9×10⁻³ S/cm) was achieved at 37.5 wt.% lithium sulfide concentration at ambient temperature, highlighting its potential in advanced solid-state battery technologies.