Polarization measurements of anode-supported solid oxide fuel cells studied by incorporation of a reference electrode

A three-electrode system configuration was applied to an anode-supported solid oxide fuel cell where the anode to cathode surface area ratio was ∼7.9, and Ni/YSZ was used as the anode, LSM as the cathode, Pt as the reference electrode, and thin YSZ film as the electrolyte. The cell was polarized potentiostatically at −0.2, −0.4, −0.6 and −0.8 V versus open circuit voltage (OCV) and the potential change versus a reference electrode were recorded to ascertain the relative electrode polarization contributions. The results of these studies suggested that, while the anode contributions to cell polarization were less significant than that observed for the cathode, they were not negligible. Furthermore, the disparity in the relative electrode polarization contribution was observed to decrease with increasing temperature and polarization. Electrode polarization studies suggested that cathodic overvoltage decreased remarkably with increasing temperature whereas anodic overvoltage increased slightly with increasing temperature. Electrode kinetic parameters were extracted from these polarization experiments and the implications of these parameters to cell performance were discussed. Lastly, electrochemical impedance spectroscopy (EIS) data was presented to further elucidate the relative contributions of the anode and cathode impedances on button cell performance.