In this work, La2NiO4+delta-xCe(0.55)La(0.45)O(2-delta) (denoted as LNO-xLDC) with various LDC contents (x = 0, 10, 20, 30, and 40 wt%) were prepared and evaluated as bifunctional oxygen electrodes for reversible solid oxide cells (RSOCs). Compared with the pure LNO, the optimum composition of LNO-30LDC exhibited the lowest polarization resistance (R-p) of 0.53 and 0.12 omega center dot cm(2) in air at 650 and 750 degrees C, respectively. The enhanced electrochemical performance of LNO-30LDC oxygen electrode was mainly attributed to the extended triple phase boundary and more oxygen ionic transfer channels. The hydrogen electrode supported single cell with LNO-30LDC oxygen electrode displayed peak power densities of 276, 401, and 521 mW center dot cm(-2) at 700, 750, and 800 degrees C, respectively. Moreover, the electrolysis current density of the single cell demonstrated 526.39 mA center dot cm(-2) under 1.5 V at 800 degrees C, and the corresponding hydrogen production rate was 220.03 mL center dot cm(-2)center dot h(-1). The encouraging results indicated that LNO-30LDC was a promising bifunctional oxygen electrode material for RSOCs.