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 Pr0.2Sr1.8CoTiO6-& delta; (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 x 10-6 K-1 at 30-900 degrees C in air. The P02STC cathode exhibits good electrochemical performance with a low polarization resistance of 0.080 & omega;cm2 at 700 degrees 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 degrees C. The electrolyte-supported single cell with a P02STC cathode shows a maximum power density of 677 mW cm- 2 at 800 degrees 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.