Abstract
To achieve the high performance of PEFC, understanding generated water phase (liquid and gas) in it is an important issue. In this study, we try to clarify the phase through open circuit voltages (OCVs) for a cell. We experimentally investigated the OCVs under the pressure of 1 atm and temperature of 40℃, with changing the humidity of supplied gases and compared theoretical potentials estimated by the Nernst equation, with considering hydrogen crossover and cathode Pt oxidation. The measured OCVs decreased with increasing the relative humidity. This characteristic corresponded to the prediction by the theory. However, the quantitative agreement between them was not obtained. This considered to be caused by the dynamic change of OCVs.
