Combining proton and anion exchange membrane fuel cells for enhancing the overall performance and self-humidification

This paper proposes a self-humidification design with enhanced overall performance by the series connection of proton (PEM) and anion (AEM) exchange membrane fuel cells that makes the best of their water production characteristics, different from the concept of hybrid membrane electrode assembly (MEA) in the literature. The performance of the PEM fuel cell based on the serpentine flow field improved by 39%, primarily under the following conditions: 2.4 A cm-2 and 10% inlet relative humidity. Further, the ohmic, activation, and concentration losses reduced, thus demonstrating the effectiveness of self-humidification. Moreover, increases in the current density of one fuel cell typically improved the performance of the other. A well-validated model of the proposed design was developed, and the simulation results revealed that the self-humidification gain could be further improved by reducing the AEM thickness: once the performance and durability of the AEM and PEM fuel cells are comparable, the proposed design will provide a practical solution for overall performance enhancement.