Herein, an innovative La0.6Sr0.4CoO3 (LSC) nanostructured air electrode, having superior catalytic activity and exceptional robustness against critical interfacial delamination-induced degradation, is reported. A ∼50 nm thin LSC air electrode decorated onto a porosity graded Gd0.1Ce0.9O2 backbone via ultrasonic-assisted infiltration showed significantly flourished ORR and OER kinetics with prolific electrochemical performance compared to the cell with conventional LSC air electrode. The SOC showed maximum power density of 2.24 W cm−2 in the fuel cell mode and maximum current density of 4.57 A cm−2 at an operating voltage of 1.6 V in the electrolysis mode at 750 °C. Results of the reversible cycling and galvanostatic stability tests indicate excellent durability, which is attributed to the elimination of detrimental O2 pressure evolved at the air electrode/electrolyte interface. Sited among the highest performances till date, this study provides a realization of a tremendously durable SOC design for the production of green hydrogen and electricity.