In this study, the electrochemical performance and the stability of Ca and Fe co-doped SmBaCo2O5+delta, SmBa0.75Ca0.25CoFeO5+delta (SBCCF), layered perovskite is examined as the air electrode for solid oxide electrolyzer cells (SOECs). In a half-cell with three-electrode configuration, the initial polarization resistance, R-P, of GDC vertical bar SBCCF is 0.16 Omega cm(2) at 800 degrees C. Under an anodic bias of 200 mV, R-P decreases to 0.03 Omega cm(2); however, under cathodic bias of 200 mV, R-P increases to 0.18 Omega cm(2), indicating that SBCCF is more active towards oxygen evolution reaction than oxygen reduction reaction. During the electrolysis test under 1 A cm (2) at 800 degrees C for 216 h, R-P of GDC vertical bar SBCCF increases to 0.52 Omega cm(2) in the first 96 h and remains at 0.52 Omega cm(2) for the remaining 120 h. In contrast, R-P of GDC vertical bar LSCF increases with a rate of 0.08 Omega cm(2)/100 h at the same time. This result demonstrates that SBCCF is a promising candidate as air electrode in SOECs for stable operation under high electrolysis current, which is critical to achieve high hydrogen production rate and to lower the cost of the system. Effective methods for the improvement of the performance of SBCCF will be developed in future studies. (C) 2017 Elsevier Ltd. All rights reserved.