Structural, Thermal, and Electrical Studies on NH4SCN Doped Polymer Gel Electrolyte System

Among various polymer electrolytes, gel polymer electrolytes are highly promising for high-performance electrochemical applications. This study focuses on characterizing proton-conducting polymer electrolyte films prepared using polyvinyl alcohol (PVA) as the polymer host and ammonium thiocyanate (NH4SCN) as the salt, employing the solution-casting technique. X-ray diffraction (XRD) analysis confirms that the polymer gel electrolytes become more amorphous. Differential scanning calorimetry (DSC) is used to determine the melting temperatures and crystallinity of pure PVA and complexed films. DSC measurements indicate a decrease in Tm with increasing salt concentration. The ionic conductivity of the gel polymer electrolytes was measured using AC impedance analysis, revealing that conductivity improves as the concentration of the dopant salt increases. Upon the inclusion of 0.8 M of NH4SCN, a maximum ionic conductivity of 6.47 × 10−4 S/cm is achieved at ambient temperature. Vogal–Tamman–Fulcher and Arrhenius behavior coexist in the temperature dependence of ionic conductivity. The analysis of the frequency dependence of dielectric and modulus formalisms indicates a strong coupling between ionic motion and polymer segmental dynamics.