Develop High-Temperature, Low-Humidity Aromatic Hydrocarbon-based H2/O2 Membranes for Proton Exchange Membrane (PEM) Fuel Cells

The development of proton exchange membrane (PEM)(also known as polymer electrolyte membrane) fuel cells has been limited by the availability of suitable membrane materials. In order to achieve acceptable performance at low cost, such fuel cells are required to work at elevated temperature and low (near 0) relative humidity (RH) for extended periods of time. For example, the U.S. Department of Energy has established performance guidelines for PEMs for automotive applications, which include a proton conductivity of 100 ms/cm under operating conditions of 120 C and 50 % RH. To date, no commercial PEMs or publicly reported PEMs can meet these performance requirements. In this proposal, general guidelines for the design of polymers for PEMs that can perform under even more stringent conditions have been established and used in the design of several series of polymers. A key feature of these systems is the use of proton carriers other than water. Another unique feature of a series of sulfonated polymers is their designed resistance to desulfonation at elevated temperatures. In Phase I, several of these new polymers will be prepared and evaluated. The overall goal of this work will be to identify one or two promising candidates for extensive study and eventual commercialization.