Analysis of crosslinked polyvinyl alcohol membranes with silica fillers in polymer electrolyte membrane fuel cells

This paper describes the synthesis, characterization, and testing of inexpensive, environment-friendly alternative for the Nafion® membranes in polymer electrolyte membrane fuel cells (PEMFC). Membranes based on crosslinked polyvinyl alcohol (PVA) with colloidal silica fillers (0.1 wt%, 1 wt%, 5 wt%. 10 wt %), were synthesized via solution casting method. Colloidal silica was added to reduce the gas crossover and maintain the membrane humidity. These membranes were characterized systematically for water uptake capacity, ion exchange capacity, ionic conductivity, chemical durability, and hydrogen crossover. V-I characteristics of fuel cells based on each membrane were analyzed under different conditions of humidity . PVA-SSA-1 wt% SiO2 cell was found to be the best among the compositions studied, with a maximum power density of 0.2 W cm-2 at 0.4 V under wet condition whereas Nafion® 115 membranes demonstrated 0.33 W cm-2 under flooded conditions. However, the PVA-SSA-1 wt% SiO2 membrane was found to be less sensitive to the humidity variations in the reactant gases compared to Nafion®115 membranes. Performance of PVA-SSA-SiO2 membranes was compared with Nafion® 115 and the results have been discussed.