Properties and morphology of Nafion/polytetrafluoroethylene composite membrane fabricated by a solution-spray process

The Nafion/polytetrafluoroethylene (Nafion/PTFE) composite membrane is fabricated by a solution-spray process. The performance and morphology of the composite membrane are studied in terms of the mechanical properties, conductivity, and permeability. The results of TEM and X-ray studies show that the morphologies of crystalline and ion cluster of the perfluorosulfonated acid (PFSA) in composite membrane are apparently similar to that of Nafion® NR211 membrane. The composite membrane has higher stiffness and strength and lower swelling than that of Nafion® NR211. The conductivity at 85 °C of 0.375 S cm−1 is relatively high in comparison to that of 0.300 S cm−1 for Nafion® NR211. The 20 kW stack with the composite membranes is evaluated. The mean single cell voltage is 0.67 V @1000 mA cm−2. The stack has behaved performance uniformity and steadily operated under low humidifying condition. In consideration of the integration of complex structure and perfect morphology, the solution-spray process is feasible for composite proton exchange membrane manufacture.