Proton conducting polymer electrolyte based on cornstarch, PVP, and NH4Br for energy storage applications

Abstract

Proton conducting polymer blend electrolytes based on cornstarch and polyvinyl pyrrolidone (PVP) with ammonium bromide (NH4Br) were prepared by the technique of solution casting. Enhancement of amorphous nature by the addition of NH4Br has confirmed by XRD. In FTIR,by the addition of NH4Br salt in the optimized blend system, there occurs a change like altering the peak intensity, peak shape, and position. This reveals the appearance of complex formation between the polymer and salt. At 358 K, 30 wt.% of NH4Br added system shows the maximum conductivity (1.31 × 10−4 S cm−1). The conduction mechanism of higher conducting polymer blend electrolytes follows the quantum mechanical tunneling (QMT) at mid-frequency and overlapping large polaron tunneling (OLPT) at higher frequency. High dielectric constant and low relaxation time of ions in polymer chain are obtained for 30 wt.% of NH4Br added polymer blend electrolyte. From Wagner’s polarization technique, it is established that conduction present in the polymer electrolytes is predominately due to ions. Faradaic pseudo capacity behaviour has observed in higher conducting sample by cyclic voltammetry. The electrochemical cell has prepared by the higher conducting polymer electrolyte and the open circuit potential (OCP) of 1.24 V has achieved from prepared electrochemical cell.