Durability of PEM fuel cell cathode in the presence of Fe~(3+) and Al~(3+)

摘要

The contamination effects of Fe~(3+) and Al~(3+) on the performance of polymer electrolyte membrane fuel cells were investigated by continuously injecting Fe~(3+) or Al~(3+) salt solution into the air stream of an operating fuel cell. Both metal ions individually caused significant cell performance degradation at a level of only 5 ppm mol in air. In addition, elevated temperature accelerated fuel cell performance degradation in the presence of Fe~(3+). Moreover, the presence of Fe~(3+) in an operating fuel cell resulted in the cell's sudden death, due to the formation of membrane pinholes that may have been promoted by the enhanced production of peroxy radicals catalyzed by Fe species. Half-cell tests in liquid electrolyte revealed that the presence of Al~(3+) in the electrolyte changed the kinetics and mechanisms of the oxygen reduction reaction by reducing the kinetic current densities and the electron transfer number.