Electrical Properties of Polyvinylidene fluoride‐H₃PO₂ Protonic Conductor; a Novel Electrolyte for Use in Fuel Cells

Abstract

Polyvinylidene fluoride (PVDF) and hypophosphorous acid (H3PO2) are combined to synthesize solid polymer electrolyte membranes using the solution cast method. Electrochemical impedance spectroscopy measurements are used to find the conductivity, and those values are plotted as a function of relative humidity (% RH) to which the membranes are kept. In agreement with the modified Onsager, the results show growth in conductivity as % RH increases, which states that ionic mobility of a polar polymeric phase increases as levels of absorbed water by the polymeric membrane increase. The high values of conductivity observed at high concentrations of H3PO2 (σ = 9.83 × 10−3 S cm−1 for x = 60% wt) are attributed to the increase of charge carriers and the dissociation of ions in an aqueous phase. The synthesized membranes are tested as electrolytes in a fuel cell and the voltage and power density plotted as a function of the current density with maxim values of the power density of 2.88 mW cm−2 for a 30% wt membrane.