No abstract

In this study, planar anode-supported solid oxide fuel cells (5 5 cm 2 ) were fabricated with cathode segmentations and tested in a channel type setup. The in-plane performance variation became significant with an increasing current density (fuel utilization), and impedance analysis on each segment indicated that the poor performance in the outlet region was due to gas conversion overpotential combined with gas concentration overpotential. Pt reference electrodes were embedded in the electrolyte layers of the segments so that the anode and cathode overpotential could be separated for each segment. It was found that the cathode overpotential was dominant for both segments, which suggested that the cathode overpotential determined the overall cell performance. On the other hand, the anode overpotential was responsible for the in-plane performance variation. Post-analysis revealed that the Ni anode was partially oxidized and its layer was delaminated in the outlet region. Thus, this study suggests that the anode overpotential related to gas conversion is a critical factor in determining Ni anode stability as well as overall cell performance in planar anode supported cells with a gas channel setup.