Ce-doped promotes the phase stability and electrochemical performance of SrCoO3-δ cathode for intermediate-temperature solid oxide fuel cells

The development of cathode with high oxygen reduction reaction (ORR) activity is crucial for intermediate-temperature solid oxide fuel cells (IT-SOFCs). SrCoO3-δ oxides, a mixed ion-electron conductivity (MIEC), are promising cathode materials. However, pure SrCoO3-δ exhibits a hexagonal or rhombohedral structure with poor electrical properties, limiting its application in IT-SOFCs. In this work, high-valence Ce4+ is doped at the A-site of SrCoO3-δ perovskite to improve the phase structural stability and electrochemical activity of SrCoO3-δ. The findings reveal that Ce4+ doping in small amounts significantly advances the conductivity and ORR activity due to enhanced structural stability. Among the series of samples, Sr0.95Ce0.05Co3-δ (SCC005) presents the best electrochemical performance. Moreover, the addition of Ce0.8Gd0.2O2-δ (GDC) further reduces polarization resistance by about ∼7 times. The peak power density of 1.3 W cm−2 is obtained at 750 °C for the SCC05-30%GDC cathode. The results indicate that A-site Ce doping is a promising strategy to enhance the ORR activity of SrCoO3-δ oxides. [Display omitted] •The phase structure is stabilized by introducing high-valent Ce4+ ions at the A-site.•Significantly improved electrical properties of SrCoO3-δ.•Single cell shows excellent performance in the medium temperature range.