Composite membrane-based PEMFCs for operating at elevated temperature and reduced relative humidity

Proton exchange membrane fuel cells (PEMFC) are the most promising sources of electrical energy, and proton conducting polymers such as Nafion have been extensively studied for use in PEMFC. However, Nafion is limited to operating temperatures below 100°C due to the tendency of the membrane to dehydrate. Nafion/solid oxide composite membranes were studied for high temperature operation of hydrogen/oxygen PEMFC. The effect of a solid oxide content in the membranes and influence of relative humidity on PEMFC performance were studied at 80° and 120°C. The composite Nafion/solid oxide membranes showed a marked improvement over unmodified Nafion membranes when operated at 120°C, 3 bar, and reduced relative humidity. At 50% relative humidity, a composite membrane showed identical performance to unmodified Nafion operated at 100% relative humidity demonstrating that the fuel cell can be operated at a lower relative humidity without any performance degradation. This is an abstract of a paper presented at the 228th ACS National Meeting (Philadelphia, PA, 8/22-26/2004).