TEMPERATURE-DEPENDENCE OF THE OPEN-CIRCUI T POTENTIAL OF PAFC CATHODES

Temperature dependence of cathode open circuit potential (OCP) at vari ous O2 concentrations was examined using a floating electrode half cel l apparatus. The OCP was found to be lower than expected from the Nern st equation when the catalyst layer was less wetted by the electrolyte solution. For the wetted catalyst layer, the OCP decreased with risin g temperature, except below 100-degrees-C. This was probably due to th e decrease of wettability of the catalyst layer and the prevention of the gas diffusion to the catalyst layer surface by the thick electroly te film formed on it.