Sensitivity study of operating conditions and liquid water transport behavior in an anion exchange membrane fuel cell aided by modeling and neutron radiography

Two types of anion exchange ionomers, powder and dispersion, are studied in this work. The gas diffusion electrode with the dispersion-type ionomer exhibits strong hydrophobicity, thus not enabling sufficient ionic exchange during the potassium hydroxide exchange process, which in turn exhibits very poor performance. Hence gas diffusion electrode prepared with the powder-type ionomer is used to study the sensitivity and effect of reactant concentration and operating conditions on anion exchange membrane fuel cell performance. The results indicate that the cell performance is most sensitive to relative humidity followed by hydrogen concentration. In contrast, oxygen is not a major performance limiting factor validated by oxygen reactant sensitivity analysis. Results from neutron imaging experiments demonstrate that active water transport from cathode to anode through electro-osmotic drag is very active, which results in flooding on the anode side, causing significant reduction of cell performance. The combined experimental and neutron results provide valuable insight into the water management strategies to improve the stability of fuel cell performance, which has a significant impact towards the development of anion exchange membrane fuel cell. • Sensitivity of AEMFCs to RH and reactant concentrations is experimentally studied. • Powder ionomers outperform dispersion ones due to improved ion exchange. • Neutron imaging reveals anode flooding as a key bottleneck at high current densities. • Experiments and modeling suggest strategies to improve water transport and durability.