Polyvinyl alcohol membrane crosslinked with sulfosuccinic acid (PVA-SSA) is studied as an alternative to the Nafion® membrane in proton exchange membrane fuel cells (PEMFC) due to its lower cost, eco-friendly nature, easy film-forming nature, and acceptable ionic conductivity. To improve the water uptake, conductivity properties in crosslinked membranes, nanofillers are used. Nano silica and sulfonated carbon nanotubes (SCNT) are reported to be two excellent fillers in Nafion® and other alternate membranes. Therefore, the effect of the addition of Silica (SiO2) and sulfonated carbon nanotubes (SCNT), as fillers in PVA-SSA membranes, has been studied in this work. Carbon nanohorns (CNH) is a relatively new allotrope of carbon. Nafion functionalized CNH (NCNH) has been evaluated in this work as an alternative for CNT as a filler in membranes.
PVA-SSA-Silica (PVA-SSA-SiO2) membranes and PVA-SSA- NCNH membranes were found to exhibit good water uptake capacity and ion exchange capacity which in turn also results in moderate conductivity. Hydrogen crossover in these membranes were similar to that of Nafion®, and the power density increased more than twice in PVA-SSA-NCNH membranes, when the losses associated with the purity of the fuel were accounted for. In spite of these advantages, mechanical strength and sensitivity to changes in humidity of reactants were two critical issues associated with these two membranes. PVA-SS-SCNT membranes displayed water uptake capacity and ion exchange capacity higher than that of Nafion®. The mechanical strength of the PVA-SSA-SCNT system was found to be good even under wet conditions. Fuel cell performance is significantly insensitive to the changes in humidity unlike Nafion based cells. In summary, PVA-SSA membranes with different fillers were studied for an economically viable, easy to fabricate, mechanically stable, self-humidifying, and green alternative for Nafion®. It was found that PVA-SSA-SCNT membranes represent a good alternative to Nafion® membranes.