Impedance and Electric Modulus Analysis of Sodium Ion‐Conducting PVA‐Based Solid Polymer Electrolytes

ABSTRACT Solid polymer electrolytes (SPEs) have attracted considerable attention for potential use in energy storage and electrochemical devices. In this study, sodium‐ion conducting solid polymer electrolytes based on polyvinyl alcohol (PVA) complexed with sodium tetrafluoroborate (NaBF 4 ) were prepared by using the solution casting technique and systematically characterized. The SPEs were investigated using impedance spectroscopy, ionic conductivity analysis, electric modulus formalism, and transference number measurements. Impedance studies revealed the frequency‐dependent behavior of the polymer matrix, highlighting key transport properties. The ionic conductivity measurements demonstrated enhanced ion transport with increasing NaBF 4 content, with the highest conductivity (8.47 × 10 −7 S/cm) observed at 20 wt.% salt concentration. The electric modulus investigation provided insights into the relaxation dynamics and charge carrier mobility within the polymer matrix. Additionally, transference number measurements confirmed that ionic species are the primary charge carriers.