Enhanced Performance of Sm0.2Ce0.8O2-δ-Based SOFCs by Acid Etching of Electrolyte

Abstract Based on the acid etching strategy proposed in 2022, a novel treating method is developed and employed in the Sm0.2Ce0.8O2-δ (SDC) based SOFC. After 25 min acid treatment, the surface roughness of SDC increases by 60% while the peeling strength of cathode/electrolyte interface can be enhanced by 129%. The peak power density at 923 K reaches 1.392 Wcm-2, 30% higher than that (1.067 Wcm-2) without treatment. Compared with little degradation observed during working at 873 K for 200 h, apparent performance degradation of single cells can be observed during thermal cycling at 673-873 K. However, the thermal cycling stability can be markedly improved by the 25 min acid etch. Combined with the electrochemical impedance spectroscopy and microstructure observation, this suggests that the significantly enhanced performance should be caused by the synergy effect of both revitalized interface and increased bonding area between cathodes and electrolytes.