A Novel Approach to Design High Resistive Polymer Electrolytes Based on PVC: Electrochemical Impedance and Dielectric Properties

Abstract

In this work, a novel hypothesis is presented which reveals the possibility of using the concept of polymer electrolyte to design high resistive solid electrolytes. Solution casting methodology was used to fabricate solid polymer electrolytes (SPEs) based on PVC and doped with ammonium thiocyanate salt (NH4SCN). The impact of ammonium thiocyanate salts on the PVC has been investigated using different quantities of salt. Various approaches have been used to characterize the electrochemical behavior of the films, like electrical impedance spectroscopy EIS, Bode plot, and dielectric properties. The EIS reveals an increase in ionic conductivity with increasing salt concentration and then dropped at the highest amount of salt due to ion aggregation. The uppermost conductivity of (2.86 x 10-8) S/cm has attained for the electrolyte incorporated 20 wt.% of salt. Our hypothesis has been clarified regarding the shortcoming ionic conductivity of PVC-based polymer electrolytes at room temperature. Bode plots differentiate the reduction in resistance or impedance with increasing salt concentration. The complex dielectric permittivity for the samples verified a non-Debye type behavior. Moreover, rising both dielectric constant and dielectric loss at low-frequency regions were a clear indication of the increase in dielectric polarization of the films. The PVC-NH4SCN system has a capacitive behavior, as demonstrated by the real part of the electric modulus. Ion conduction occurs through the viscoelastic relaxation dynamic, as evidenced by peaks appearance in the imaginary portion of the electric modulus.