Degradation studies of ceria-based solid oxide fuel cells at intermediate temperature under various load conditions

Abstract

Despite several disadvantages with the electronic conduction of ceria, researchers report the high performance of ceria-based solid oxide fuel cells (SOFCs) at intermediate temperatures with advanced cathode materials. However, it appears the long-term stability of ceria-based SOFCs in the anode-supported cell configuration have still not been proved experimentally at practical operating conditions. In particular, the chemical expansion of ceria electrolytes can cause potentially irreversible failure of SOFCs under large PO2 gradients. Hence, we investigate the degradation behavior of NiO-Nd0.1Ce0.9O2-δ anode-supported cells with Nd0.1Ce0.9O2-δ electrolyte in dynamic electrical modes, load trip (0.7–0 A cm−2), load cycle (0.2–0.12 A cm−2), and constant load operation (0.2 A cm−2), at 650 °C. We identify the specific degradation phenomenon of ceria-based cells by analyzing the electrochemical characteristics in post-mortem investigations after durability testing under various electrical load conditions. Additionally, we suggest a possible operation strategy to mitigate the performance degradation of cells under various electrical stresses through understanding of the main degradation mechanism.