Effect of PTFE content in gas diffusion layer based on Nafion®/PTFE membrane for low humidity proton exchange membrane fuel cell

This research was carried out to prepare high performance membrane-electrode assembly for proton exchange membrane fuel cell at low humidity condition. It had investigated the effect of the Nafion®/PTFE proton exchange membrane, impregnating porous PTFE membrane with Nafion® solution, in the gas diffusion medium and microporous layer on the cell performance under various humidity conditions. The Nafion®/PTFE decreases the back diffusion distance of product water from cathode to anode side at low humidity condition, caused by the property of high tensile strength. It is found that the optimum PTFE content is 40 wt% of the gas diffusion medium and 30 wt% of the microporous layer at low humidity condition, respectively. The optimum PTFE treatment in the two layers can facilitate the reactant gas and the back diffusion of product water from cathode side to anode side to provide sufficient proton conductivity of membrane. The highest current density was 955 mA/cm2 occurred at the cell potential of 0.6 V.