Synthesis and Characterisation of Anhydrous Proton Conducting Membranes Based on Sulfonated Poly(vinyl alcohol) and Silicotungstic Acid with or without Silica for Fuel Cell Applications

Abstract

Several new composite proton conducting polymer electrolyte membranes of different thicknesses (50-500 μm) based on polyvinyl alcohol (PVA), sulfosuccinic acid (SSA) and silicotungstic acid (SiWA) with or without silica have been developed for polymer electrolyte membrane fuel cells (PEMFCs). The chemical characterization of the membranes has been studied by Fourier Transform Infrared Spectroscopy (FT-IR). The thermal stability of the membranes has been studied using the techniques of thermogravimetric analysis (TGA) between room temperature and 600°C. The water uptake, ionic conductivity in NaCl solution and ionic exchange capacity of these membranes were determined. Water uptake of these membranes ranged between 31% and 88%. The ionic conductivities of these membranes ranged between 1.06.10-3 S.cm-1 to 6.72.10-1. The best water uptake and ionic conductivity were those of the membrane PVA-SSA-SiWA-10 SiO2 containing 10% of silica weight. The membrane PVASSA-SiWA have ionic conductivity of about 3.10.10-3 S.cm-1 in 1M NaCl, and generally increases with SiWA content, and reaches a maximum ionic conductivity of about 6.72.10-3 S.cm-1 in 1M NaCl for the membrane PVA-SSA-SiWA-10SiO2 The ion exchange capacity of this membrane was 1.75 mmol.g-1.