Quaternized poly(arylene perfluoroalkylene)s (QPAFs) for alkaline fuel cells – a perspective
The recent progress of our research on quaternized poly(arylene perfluoroalkylene)s (QPAFs) as anion exchange membranes (AEMs) for alkaline fuel cell applications is reviewed. First, the effect of the perfluoroalkylene group in the polymer main chains on the AEM properties is discussed. We emphasize that the polymer main chains of QPAFs remain intact in the harsh alkaline environment, and QPAFs have desirable AEM properties, such as well-developed phase-separated morphology, good anion transport, mechanical robustness, and gas barrier properties. We then discuss the effect of the molecular structures of the quaternary ammonium groups on the alkaline stability of the QPAF membranes. A number of pendant ammonium head groups are much more alkaline-stable than the classical benzyltrimethylammonium groups. Comparison of our QPAFs with other state-of-the-art AEMs implies that well-designed aromatic AEMs are potentially applicable to alkaline fuel cells that use hydrogen or hydrazine as a fuel.