Application of CuNi–CeO2 fuel electrode in oxygen electrode supported reversible solid oxide cell

The oxygen electrode-supported reversible solid oxide cell (RSOC) has demonstrated distinguishing advantages of fuel flexibility, shorter gas diffusion path and more choices for fuel electrode materials. However, there are serious drawbacks including the difficulty of co-firing the oxygen electrode and electrolyte, and the inefficient electrochemical performance. In this study, a (La0.8Sr0.2)0.95MnO3-δ (LSM) supported RSOC with the configuration of La0.6Sr0.4Fe0.9Sc0.1O3-δ (LSFSc)-YSZ/YSZ/CuNi–CeO2-YSZ is fabricated by tape casting, co-sintering and impregnation technologies. The single cell is evaluated at both fuel cell (FC) and electrolysis cell (EC) mode. Significant maximum power density of 436.0 and 377 mW cm−2 is obtained at 750 °C in H2 and CH4 fuel atmospheres, respectively. At electrolysis voltage of 1.3 V and 50% steam content, current density of −0.718, −0.397, −0.198 and −0.081 A cm−2 is obtained at 750, 700, 650 and 600 °C respectively. Much higher electrolysis performance than FC mode is exhibited probably due to the optimized electrodes with increased triple phase boundary (TPB) area and faster gas diffusion (oxygen and steam) and electrochemical reactions for water splitting. Additionally, the short-term stability of single cell in H2 and CH4 are also studied.