(35f) PVA-g-PAA Substituted Benzimidazolium Group Membrane for Fuel Cell Applications

In this work the focus has been on membrane and in an effort to replace the Nafion membrane, we synthesized the crosslinking agent  3-Amino -4-[3-(triethyl ammonium sulfonato) phenyl amino] phenylene (Compound-I). We subsequently synthesized grafted polyvinyl alcohol polymers and reacted them with cross-linking agent. The grafted polymers gave benzimidazole substitution with acid functional group on heating and treating with 20% Orthophosphoric acid. The polymer was characterized using various characterization techniques and all were essentially similar in nature showing that benzimidazole grafted polymers can serve as substitute for polybenzimidazole membranes. 

            The membranes were tested in laboratory made Fuel cell set up. Fuel cell bipolar plates were made of SS316 which were fabricated using computed numerically controlled machine to get serpentine channels on anode and parallel channels on cathode side. We have synthesized Pt/Ru(anode) & Pt(cathode) loaded on carbon by silica immobilization technique. The maximum current density we are getting is around 50mA/cm_­²  at 0.575 V and the maximum power density obtained is around 33mW/cm²  _­for Compound-I membrane^. Nafion 117 membrane was also tested under the same conditions to get 33mA/cm_­²  at 0.435V & power density of 15mW/cm_­² _. Also the methanol permeability was order of magnitude less compared to Nafion.