Sc-doped Co-based perovskites as IT-SOFC cathode with high oxygen reduction reaction and CO2 tolerance

The development of cathode materials with high oxygen reduction reaction (ORR) activity and stability in intermediate temperature (IT) environments is a key factor in the commercialization of solid oxide fuel cells (SOFC). In this paper, the ORR activity of the cathode is improved by doping high-valent Sc 3+ ions at the B-site of the Sr 0.5 La 0.5 Co 0.8 Cu 0.2-x Sc x O 3–δ (x = 0, 0.02, 0.04), in which Sr 0.5 La 0.5 Co 0.8 Cu 0.18 Sc 0.02 O 3–δ (SLCCS2) shows the best electrochemical performance , and the area-specific resistance of SLCCS2 at 700 °C is only 0.047 Ω cm 2 , much lower than the 0.087 Ω cm 2 of Sr 0.5 La 0.5 Co 0.8 Cu 0.2 O 3–δ (SLCC), and the peak power density of SLCCS2 reached 1.098 W cm −2 , which is 1.84 times that of SLCC (0.598 W cm −2 ). In addition, SLCCS2 effectively reduces the thermal expansion coefficient , improves thermal matching with traditional electrolytes, and overcomes the problem of insufficient long-term SOFC stability caused by the high thermal expansion coefficient of Co-based perovskite to a certain extent. SLCCS2 also exhibits excellent CO 2 tolerance. Considering comprehensively, SLCCS2 is expected to become an IT-SOFC cathode material with development potential.