Effect of Structural Features on Ionic Conductivity and Dielectric Response of PVA Proton Conductor-Based Solid Polymer Electrolytes

Abstract

In this study, the effect of structure on the ionic conductivity and dielectric response of polyvinyl alcohol solid polymer electrolyte films doped with ammonium nitrate (NH4NO3) was investigated. Structural studies show that the solid polymer electrolytes in a suitable salt ratio enhance the amorphous fraction of the host matrix and facilitate the fast movement of H-ions, resulting in the enhancement of electrical conductivity. The highest ionic conductivity at room temperature (5.17 × 10−5 S/cm) was achieved by incorporating 30 wt.% of NH4NO3, which shows the maximum ion dissociation in the host matrix due to ion–polymer interaction. The reduction in the ionic conductivity at higher salt concentrations (above 30 wt.%) is the consequence of a decrease in the carrier concentration and its movement, respectively, due to the formation of ion pairs and a reduction in the amorphous fraction of the system. A broad asymmetric peak of the imaginary part of the electrical modulus suggests a temperature-dependent non-Debye relaxation process for the present system.