ABSTRACT
In order to determine the water vapor pressure in the porous anode of a solid oxide fuel cell (SOFC) during discharge, a small steam sensor was attached to the surface of the anode. The sensor is a steam concentration cell and is composed of a stabilized zirconia electrolyte with porous platinum electrodes.
It was observed that the water vapor pressure increased with increasing discharge current of the SOFC. From the steam pressure measured by this method, the hydrogen partial pressure in a porous Ni–YSZ cermet and Pt–plated anode was determined and the anodic overpotential due to concentration polarization was calculated. It was shown that the major part of the anodic overvoltage measured with a dc interruption method was due to concentration polarization of hydrogen.
