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 Sr2ScTi1-xMoxO6; 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 Sr2ScTi0.5Mo0.5O6, whereas the in-situ exsolution of Ti-ions enables the Sr2ScTi0.9Mo0.1O6 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. Display omitted •Novel double perovskite Sr2ScTi1-xMoxO6; x = 0.5, and 0.1 electrode for SSOFC.•Electrode, x = 0.5, exhibits higher ORR, while x = 0.1 shows excellent HOR.•In situ ex-solution of Ti exhibits for x = 0.1 electrode.•Pmax of the SSOFC with x = 0.5 is 3.5 W at 800 °C in CH4 and air.•in-operando gas switching suppresses the degradation of performance.