Investigation of a Correlation Between IV Performance and Cathode Structure for MEAs Using Mesoporous Carbon Supports

The cathode catalyst layer in PEFC plays an important role for further improvement of performance and durability toward heavy–duty vehicles. Since carbon is the main component to define the porous cathode structure, realization of optimal structure of carbon is desired. Therefore, in this study, using lab-made Pt/mesoporous carbon and Pt/mesoporous carbon fiber, and commercially available Pt/Ketjen Black as cathode materials, membrane electrode assemblies were made, and evaluated electrochemically and structurally. Then, a correlation between IV performance and three dimensional structure was investigated. From the three dimensionally reconstructed images, we found that large carbon particles most likely lead to higher ohmic resistance owing to interparticle resistance between the particles. Homogeneous distribution of large pores was found to lower concentration overvoltage.