Cobalt-free La0.5Sr0.5Fe0.9Mo0.1O3-δ (LSFM) oxide is particularly investigated as a durable and efficient oxygen electrode material for the reversible solid oxide cells (RSOCs) in this study. Pr6O11 nano-catalysts are introduced into LSFM oxygen electrode as synergistic catalysts to enhance and optimize the electrode reactions. Results demonstrate an effectively promoted oxygen reduction and evolution reaction kinetics of the Pr6O11 decorated LSFM electrode. Polarization resistances (Rp) of LSFM electrode are dramatically reduced with the increasing Pr6O11 nano-catalysts and the lowest Rp of 0.039 Ω cm2 is obtained at 800 °C, which is ∼97% lower than that of the LSFM electrode. The Pr6O11 decorated LSFM oxygen electrode also displays a superior durability under cyclic anodic and cathodic polarizations. Furthermore, both the maximum power density and electrolytic current density of the Pr6O11 decorated cell are more than 2 times that of the LSFM cell. Results make clear reliability of the Pr6O11 decorated LSFM to be a promising oxygen electrode for RSOCs.