Durability Of Nafion®-Teflon®- Phosphotungstic Acid Composite Membranes In Pem Fuel Cells At 100°C And 25% Rh

Composite membranes consisting of treated Nafion®-Teflon®- phosphotungstic acid (NPTA) were developed for high temperature/low RH operation and demonstrate conductivity slightly above that of Nafion®. A proton exchange membrane (PEM) fuel cell using a Series 4 membrane was tested at 100°C, 25% RH, and 150 kPa total pressure for 1000 hours. The membrane resistance and hydrogen crossover were very stable over the 1000 hours. After 1000 hours, at 400mA/cm2, there was a 90mV voltage drop (initial cell voltage ∼500 mV), which was due to catalyst degradation. copyright The Electrochemical Society