Stability of Cations for Anion Exchange Membrane Fuel Cells

The hydrothermal stability of quaternary ammonium hydroxides was evaluated to better understand the degradation of anion exchange membranes used in alkaline fuel cells. Benzyltrimethylammonium hydroxide and phenyltrimethylammonium hydroxide were examined as representative cations for membrane materials. The benzyltrimethylammonium hydroxides displayed much better stability than the phenyltrimethylammonium hydroxides under similar conditions. Additionally, as the concentration of the ammonium hydroxides in water increased, the stability of the cation decreased.