Improvement of PEFC Performance Stability under High and Low Humidification Conditions by Use of a Gas Diffusion Layer with Interdigitated Gas Flow Channels

A new design concept for polymer electrolyte fuel cells, which included a flat-metal separator and a gas diffusion layer (GDL) with interdigitated gas flow channels (FCs), was developed in our previous research. This design led to improved performance compared to that obtained with the conventional design of a metal separator with FCs and a flat GDL. Applications of the interdigitated gas flow channels formed on the separator, however, have conventionally faced two issues associated with low performance: one occurs under high humidity conditions because of nonuniform gas flow due to accumulated water in the GDL; the other is caused by forced water discharge from the GDL under low humidity conditions. In this study, both conventional and new cell designs are tested with single cells of 1 cm 2 active area, and the performances are compared at high and low humidity with various conditions of gas supply. From these results, we have found that the new design of the GDL with interdigitated channels has a clear advantage over the conventional interdigitated cell in being able to maintain high performance under conditions of both water excess and water shortage.