The polarization behavior of Ba0.5Sr0.5Co0.8Fe0.2O3-delta-BaCe0.4Zr0.4Y0.2O3-delta(BSCF-BCZY) electrode under steam electrolysis conditions was studied in detail. The composite oxygen electrode supported by BCZY electrolyzer has been assessed as a function of temperature (T), water vapor partial pressures (pH(2)O), and bias polarization voltage for electrodes of comparable microstructure. The Electrochemical impedance spectra show two depressed arcs in general without bias polarization. And the electrode resistance became smaller with the increase of the bias polarization under the same water vapor partial pressures. The total resistance of the electrode was shown to be significantly affected by temperature, with the same level of pH2O and bias polarization voltage. This result highlights BSCF-BCZY as an effective oxygen electrode under moderate polarization and pH(2)O conditions. (C) 2017 Elsevier B.V. All rights reserved.