This Small Business Innovation Research (SBIR) Phase I project will address the problems associated with polymer electrolyte membranes (PEMs) for direct methanol-air fuel cells. The advantages of fuel cells based on PEMs include simplicity of design, light weight, low operating temperature, improved catalytic activity, elimination of electrolyte loss from vaporization or redistribution within the cell stack, and reduced corrosion of cell materials. The membranes of choice in the majority of PEM fuel cells have been based on perfluorosulfonic acid polymers. When considered for use in direct methanol-air fuel cells, the greatest limitations of the perfluorosulfonic acid membranes are their cost, the rate of methanol transport across the membrane, and the requirement to maintain hydration of the membrane. The incompatibility of perfluorosulfonic acid membranes with methanol leads to a limited lifetime of the fuel cell as the membrane dissolves. Phase I will develop a solid polymer electrolyte that is not based on perfluorosulfonic acid polymers like Nafion, for application in direct methanol-air fuel cells. This non-perfluorosulfonic acid-based PEM will have high proton transport rates, will not transport methanol, will be stable in the presence of methanol, will be easy to process, and will operate at higher temperatures where carbon monoxide is less of a problem for the catalyst. This new solid polymer electrolyte material is expected to find use in PEM-based, direct methanol-air fuel cells, that would power the electric-car Next Generation Vehicle (NGV). Other potential applications include its use in polymer electrolyte batteries, electrochemical sensors, polymer-based acid catalysts, and chlor-alkali membranes.
