Polymer electrolyte membrane fuel cell (PEMFC) is regarded as a promising power source with the advantages of high power density and low operating temperature. However, there still remains water management problem. Water flooding is a phenomenon that the pores of the catalyst on gas diffusion layer are filled up with the excessive water produced near cathode side. And the pathway of oxygen (or air) could be blocked leading to the acceleration of the mass transfer limitation and degradation of durability because of the carbon corrosion reaction between carbon and water at cathode. Therefore, it is important to remain the right amount of water in membrane electrode assembly to keep the reaction working smoothly. In recent investigations,^1,2 various types of catalyst layer structure have been studied in order to keep a proper humidity level in membrane electrode assembly (MEA) and reduce the oxygen transport resistance.

In this study, we incorporate a highly graphitized carbon nanofiber (CNF) into cathode catalyst layer for improvement mass transfer in PEMFC, and found out that graphitic CNF might serve as a pathway of water drainage and also diminish the ohmic losses due to the improved electrical conductivity of the electrode.

References

1. J. Joo, M. Choun, K. Kim, S. Uhm, Y. D. Kim and J. Lee, Curr. Appl. Phys., 14, 1374 (2014).
2. M. Choun, D. Nauryzbayev, D. Shin and J. Lee, Catal. Today, 262, 155 (2016).