In-operando gas switching to suppress the degradation of symmetrical solid oxide fuel cells

The degradation of electrochemical performance during the long-term operation of the solid oxide fuel cell is a critical issue. This challenge is confronted through an innovative approach of in-operando gas switching. Here, we developed a novel double perovskite electrode Sr₂ScTi_1-xMo_xO₆; x = 0.1 and 0.5, for the symmetrical solid oxide fuel cell. The crystallite phase and chemical stability of the perovskite are examined by X-ray diffraction whole powder pattern fitting. The electrochemical impedance analysis confirmed that the electrodes are exhibiting significant catalytic activity for hydrogen and methane oxidation, as well as the reduction of oxygen. Evolution of the cubic ScTiO₃ due to the topotactic oxidation, improve the oxygen reduction activity of Sr₂ScTi_0.5Mo_0.5O₆, whereas the in-situ exsolution of Ti-ions enables the Sr₂ScTi_0.9Mo_0.1O₆ to exhibits of higher catalytic activity for fuel oxidation. The electrochemical performance, stability, and the effect of in-operando gas switching are investigated on large area (5 × 5 cm²) symmetrical solid oxide fuel cells supplying humidified CH₄ and air. The galvanostatic test concludes the in-operando switching suppress the performance degradation of the SSOFC completely.