Evaluation of Electrode Overpotentials on Yttrium-Doped Barium Zirconate Electrolyte by Current Interruption Using Three-Electrode Cell

Abstract

Yttrium-doped barium zirconate (BZY) is accepted as one of the most promising electrolyte materials for protonic ceramic fuel cells (PCFCs). For the development of fuel cells with the BZY electrolytes, evaluation of electrode performance is important. In this work, electrochemical measurements of an electrolyte supported cell, Pd (wet H2) | BaZr0.8Y0.2O3-δ | La0.6Sr0.4Co0.2Fe0.8O3-δ (wet O2), were performed at 600°C in a three-electrode system. The ohmic resistances of the electrolyte under open circuit condition and DC current flow were evaluated by AC impedance and current interruption measurements, respectively. Overpotentials of cathode and anode are determined to be 0.587 and 0.053 V at 100 mAcm−2, respectively, and exhibit a logarithmic relationship with current density. The results clearly indicate that high cathode overpotential is a significant problem restricting the fuel cell performance.