Novel CO2-tolerant Co-based double perovskite cathode for intermediate temperature solid oxide fuel cells

For the commercial application of solid oxide fuel cells (SOFCs), CO₂-tolerant cathode materials with high electrochemical activity are required. Here, we discuss the performance of double perovskite Pr_0.2Sr_1.8CoTiO_6?δ (P02STC) as a potential cathode material for SOFCs. P02STC has a cubic structure and keeps lattice structure stable in the CO₂ atmosphere. The average thermal expansion coefficient is 17.8 × 10^–6 K^–1 at 30–900 °C in air. The P02STC cathode exhibits good electrochemical performance with a low polarization resistance of 0.080 Ωcm² at 700 °C. The P02STC cathode shows good structure stability, electrochemical performance stability, and excellent tolerance to CO₂ poisoning for the symmetrical cells based on the 350 h stability test in air and the 150 h stability test in O₂ containing 5%CO₂ at 700 °C. The electrolyte-supported single cell with a P02STC cathode shows a maximum power density of 677 mW cm^? 2 at 800 °C. The single cell operates stably for 250 h at a constant current of 0.3 A/cm² without obvious degrading performance. According to all of the experimental results, the P02STC sample might be a promising candidate cathode for SOFCs.