In-Situ Catalyst Layer (CL) Characterization

Studies of water transport in the CL have been limited to modeling analyses. Since water condensation in the CL has a strong impact on the cell performance and lifetime, it is important to understand water ingress and egress at the CL and at its interface with the GDL. We designed a special micro-visualization system, coupled with a catalyst-visible fuel cell. The key feature of our optical system is a much larger working distance than that of a conventional microscope. This enabled visualizing the dynamics of micro-droplets on the CL surface (formation, growth, coalescence and removal) under realistic operating conditions and cell performance. Mechanisms of water condensation and transport within the CL pores were discussed with respect to the pore architecture and wetting properties. The experimental results should prove useful in clarifying the role of the CL in water management, and in refining models used to optimize PEMFC performance.

Zhang F.Y., Spernjak D., Prasad A.K., and Advani S.G., "In situ characterization of the catalyst layer in a polymer electrolyte membrane fuel cell," Journal of the Electrochemical Society, Vol. 154, pp. B1152-B1157, September 12, 2007. doi:10.1149/1.2777987