Exceptionally stable double perovskite Sr2-xFeTaO6-δ as fuel electrode for solid oxide cells

Developing fuel electrodes with excellent structural stability and high catalytic activity under various fuel conditions is highly desirable for large-scale applications of solid oxide cells (SOCs). In this study, double perovskite Sr 2- x FeTaO 6-δ ( x  = 0, 0.1, 0.2, 0.3) materials were designed as fuel electrodes for SOCs. Sr 1.8 FeTaO 6-δ (S18FT) was synthesized in air, and its structural stability could be maintained in both 5 % H 2 /Ar and pure CO 2 after calcination at 850 ℃ for 10 h. The thermal expansion coefficient of S18FT was 11.8 × 10 −6 K −1 at 50–850 ℃. To further improve the electrochemical performance of the S18FT electrode, it was impregnated with Pd(NO 3 ) 2 to form a composite electrode (Pd-SFT–SDC). When hydrogen, propane, ethyl ethanol, and biochar were used as fuels, the maximum power densities of the fuel cells at 850 ℃ were 1114, 370, 474, and 291 mW cm −2 , respectively. The fuel cell operated stably for 300 h when using propane. When the solid oxide electrolysis cell mode was used for the co-electrolysis of CO 2 /H 2 O, the current density was −0.835 A cm −2 at 1.3 V and 800 ℃. These results indicated the potential for the use of the Pd-SFT–SDC composite material as a fuel electrode for SOCs.