Electrical Properties of Nano‐ZnS Incorporated Polymer Electrolyte Films: A Conductivity Analysis for Energy Devices

ABSTRACT The tunable electrical conductivity of nano‐ZnS‐doped polymer electrolyte films presents substantial possibilities for a variety of devices. The main goal of this study is to find the best way to make polymer electrolyte films work better in electrochemical devices by looking into how their electrical properties change with concentration. We selected poly(vinyl alcohol) (PVA) and potassium iodide (KI) as the polymer electrolyte matrix based on their composition, which exhibited maximum conductivity. Nano‐ZnS was synthesized via the chemical precipitation method and incorporated as a nanofiller into the PVA‐KI matrix at varying concentrations using a controlled stirring process. Solution casting approach was adopted to fabricate the polymer electrolyte films. We studied the electrical properties of the free‐standing solid polymer composite films using impedance spectroscopy, the structural properties using X‐ray diffraction (XRD) and scanning electron microscopy (SEM), and the optical properties using Fourier‐transform infrared spectroscopy (FTIR). The results indicate that the ionic conductivity of the films increases with increasing nano‐ZnS concentration up to a critical threshold, beyond which conductivity plateaus or declines. The maximum conductivity of 4.1 × 10 − ⁴ S/cm was obtained for 7 wt.% concentration. We further analyze this conductivity behavior in relation to the dispersion of nano‐ZnS within the polymeric matrix and its influence on ionic transport mechanisms. These findings offer insights into the optimal nano‐ZnS concentration required to achieve high conductivity in polymer composite electrolytes, contributing to the development of efficient and durable solid‐state batteries and electrochemical sensors.