FUEL CELLS – PROTON-EXCHANGE MEMBRANE FUEL CELLS | Membranes: Advanced Fluorinated

Perfluorosulfonic acid (PFSA) ionomers are known since the late 1960s, when the Nafion® ionomers were employed as polymer electrolyte in a GE fuel cell designed for NASA spacecraft missions. Since then, Nafion polymers have found wide application, especially in the chlor-alkali industry as membrane materials, but also, in more recent years, in proton exchange membranes in fuel cells. Due to electrochemical stability requirements, perfluorinated materials have been preferred as the best candidates for satisfying the system needs. Especially for automotive applications the request for materials for high-temperature application, in the range of the 120 °C, increased since the second half of the 1990s, and Nafion is known to lose its mechanical integrity when 100 °C is reached. For the sake of system simplification also, the need for ionic conductors able to work with very reduced humidification of reactants was increasing in importance. Several companies are active in the development of ‘alternative’ PFSA ionomer and membranes able to work in the high-temperature region of proton-exchange membrane fuel cell with reduced humidification trying to match the requirements of mechanical stability without losing the advantages of chemical inertness of fluorinated materials.