Investigation of Interfacial Water Transport at the Gas Diffusion Media by Neutron Radiography

Abstract

For cost reduction of fuel cell, it is necessary to realize high current density operation, which requires a thorough understanding of mass transport. However, especially interfacial liquid water transport between carbon paper (CP), micro porous layer (MPL), and catalyst layer (CL) are not fully understood. Coupled cell performance evaluation, liquid water visualization by neutron radiography and numerical modeling were performed with three types of gas diffusion media (GDM): MPL free; CP with MPL; and CP free. It revealed that the presence of a gap at the CL-GDM interface has a significant effect on water accumulation and that the MPL could minimize this effect. At the same time, CP free case showed the best performance and the lowest liquid water content due to multiple impacts of interfacial liquid water transport both at CL-MPL and MPL-channel interfaces. These results confirm the importance of interfacial design between each component of fuel cell for further cost reduction.