Interfacial energy barrier: A crucial factor affecting cathodic polarization resistance of solid oxide fuel cells

The decrease in cathodic polarization resistance is crucial for the development of advanced solid oxide fuel cells (SOFCs). This can be achieved by using functional ceramic catalysts for enhancing the oxygen reduction reaction. In addition to the bulk and surface properties of the catalysts, the cathode/electrolyte interfacial energy barrier also affects the cathodic polarization resistance of SOFCs. Accordingly, in this study, cells with different interface structures were designed and tested to determine the effect of the interface on the cell performance. The cell with the cathode/electrolyte interface formed by employing Nd1/2Ba1/2Co1/3Fe1/3Mn1/3O3−δ as the cathode and Gd0.1Ce0.9O1.95 as the electrolyte exhibited an interfacial polarization resistance of 0.12 Ω cm2 at 750°C, which was 69.8% of the total cathodic polarization resistance. By comparison, the cell with the cathode/electrolyte interface formed by employing Nd1/2Ba1/2Co1/3Fe1/3Mn1/3O3−δ as the cathode and La0.8Sr0.2Ga0.8Mg0.2O3 as the electrolyte demonstrated a decreased in the cathodic polarization resistance from 0.140 to 0.088 Ω cm2 at 750°C. Therefore, different interfacial energy barriers resulted in variable oxygen anion diffusions through the cathode/electrolyte heterogeneous interface. The above-mentioned findings can provide useful data for the design and development of high-performance SOFCs.