Efficient intermediate-temperature steam electrolysis with Y : SrZrO3-SrCeO3 and Y : BaZrO3-BaCeO3 proton conducting perovskites

Ceramic proton conductors have the potential to become important components in future clean and efficient energy technologies. In this manuscript, barium cerium yttrium zirconate (Ba(Zr0.5Ce0.4)(8/9)Y0.2O2.9) and strontium cerium yttrium zirconate (SrZr0.5Ce0.4Y0.1O2.95), proton conducting perovskites were employed as solid oxide electrolysis cell (SOEC) electrolytes for hydrogen production via intermediate temperature steam electrolysis at 550 and 600 degrees C. Cathode-supported button cells examined for a 12 m Ba(Zr0.5Ce0.4)(8/9)Y0.2O2.9 electrolyte, with Ni-SrZr0.5Ce0.4Y0.1O2.95 as the H-2-electrode, and porous Ba0.5La0.5CoO3 as the anode reached current densities of 0.2 and 0.5 A cm(-2) with applied voltage of 1.45 V, at 550 and 600 degrees C, respectively. Moreover, a hydrogen evolution rate of 127 mol cm(-2) per minute was achieved at 0.5 A cm(-2), translating to a current efficiency of 82%. In addition, excellent cell performance was obtained using SrZr0.5Ce0.4Y0.1O2.95 as an electrolyte. Current densities of 0.2 and 0.5 A cm(-2) were obtained at 600 degrees C with applied voltages of 1.28 and 1.63 V, achieving faradaic current efficiencies of 88 and 85%. The NiO-SrZr0.5Ce0.4Y0.1O3-delta composite cathode was more favorable for the densification of the supported Ba(Zr0.5Ce0.4)(8/9)Y0.2O2.9 electrolyte during sintering and could be promising for use as a cathode substrate in proton-conducting SOECs.