Nafion-Teflon-Zr(HPO[sub 4])[sub 2] Composite Membranes for High-Temperature PEMFCs

Nafion membranes suffer high resistance due to dehydration when they are used at elevated temperatures and atmospheric pressures (Nafion at and 31% relative humidity). Thinner composite membranes containing Nafion and zirconium hydrogen phosphate, were prepared and showed lower resistance at these conditions. Thermogravimetric analysis showed that the composite membrane was stable below 200°C in oxygen. Hydrogen crossover of a 18 μm thick composite membrane was only at When the temperature of a cell using this membrane was raised from 80°C (100% relative humidity) to 120°C (31% relative humidity), the main performance loss at the elevated temperature was from low protonic conductivity and low oxygen permeability in the cathode catalyst layer and dehydration of the membrane.