The efficient conversion of electrical energy to chemical energy poses new fundamental challenges in the fields of technology, economy and ecology. Currently, development of steam electrolysis technology via solid oxide electrolysis cells (SOECs) is considered to be one of the most effective ways to produce hydrogen. Here, we present testing of the SOEC based on a new combination of the functional materials, BaCe0.5Zr0.3Dy0.2O3-delta as a proton-conducting electrolyte and Nd(1.95)Ba(0.05)Nia(4+delta) (NBN) as an oxygen electrode, which are chemically and thermally compatible. To demonstrate the performance capability and establish the most favorable operating conditions, the cell was comprehensively characterized within a wide range of temperatures (500-750 degrees C), applied electrolysis potentials (similar to 0.8-2 V) and water vapor partial pressure in anode atmospheres (0.03-0.5 atm). The results reveal that a high current density 1.21 A cm(-2) is achieved under the selected conditions (750 degrees C, 1.6 V, 0.03 atm); it increases up to 1.40 A cm(-2) with the pH(2)O increasing from 0.03 to 0.5 atm. Comparative analysis presented for similar SOEC systems allows considering the NBN as a highly attractive oxygen electrode, having a polarization resistance (R-p) of 0.05 Omega cm(2) at the selected conditions and promoting electrochemical steam electrolysis because no degradation of the R-p value (0.03 Omega cm(2)) at highly moisturizing conditions, pH(2)O = 0.50 atm.