Polymer electrolyte membranes for high-temperature fuel cells based on aromatic polyethers bearing pyridine units

This review is focused on the design and synthesis of new high-temperature polymer electrolytes based on aromatic polyethers bearing polar pyridine moieties in the main chain. Such materials are designed to be used in polymer electrolyte fuel cells operating at temperatures higher than 100 degrees C. New monomers and polymers have been synthesized and characterized within this field in respect of their suitability for this specific application. Copolymers with optimized structures in order to combine excellent film-forming properties with high mechanical, thermal and oxidative stability and controlled acid uptake have been synthesized which, after doping with phosphoric acid, result in ionically conducting membranes. Such materials have been studied in respect of their conductivity under various conditions and used for the construction of membrane-electrode assemblies (MEAs) which are used for fuel cells operating at temperatures up to 180 degrees C. New and improved, in terms of oxidative stability and mechanical properties in the doped state, polymeric membranes have been synthesized and used effectively for MEA construction and single-cell testing. (C) 2009 Society of Chemical Industry