Investigation of Two-Phase Behavior of Gas Diffusion Layers in PEFC

摘要

Flooding of gas diffusion layers (GDLs) or flow fields is one of the major problems in high performance PEFC.In this study,flooding in PEFC is investigated using segmented and single cell experiments.The behavior of four different commercial GDL was investigated in two and one-phase conditions by galvanostatic fuel cell experiments.The influences of varying the reactant humidity or the gas composition were studied.The results show that none of the studied GDLs at the anode side are significantly flooded.On the other hand,when some of the GDLs are used on the cathode side they are significantly flooded.It is also shown that humidity and pressure of the anode side have major effect on the flooding at the cathode.Furthermore,it is shown that the gas composition sweeps at constant volume flow rate and at high current densities is an efficient and accurate way to study mass transfer limitations,at the anode as well as the cathode side.