Proton conducting diazanium hydrogen phosphate/poly(vinyl alcohol) electrolytes: Transport, electrical, thermal, structural, and optical properties

Abstract

Proton conducting solid polymer electrolyte films, which are composed of diazanium hydrogen phosphate (DAHP) and poly(vinyl alcohol) (PVA), were prepared by a solution casting method. The prepared films were characterized by ultraviolet-visible, X-ray diffraction, and differential scanning calorimetry. The optical activation energy and band gap increases with increase in DAHP content in PVA. The direct current (DC) and alternating current (AC) conductivity studies have been carried out using an impedance analyzer. The sample containing 15 wt% DAHP shows highest AC conductivity of the order of 10−4 S cm−1 and DC conductivity about 4.27 × 10−7 S cm−1 at ambient conditions. The crystallinity has decreased and glass transition temperature ( T g) has increased with increase in DAHP content. The Williams–Landel–Ferry and Vogel–Fulcher–Tamman equations were used to calculate dynamic fragility ( m) and apparent activation energy ( E g) from T g values. The Rice and Roth model was successfully applied to determine the transport parameters for DAHP/PVA electrolytes. This article mainly focused on understanding the contribution of different parameters to conductivity phenomenon in solid polymer electrolytes.