Intermediate temperature steam electrolysis using strontium zirconate-based protonic conductors

Steam electrolysis using SrZr0.9Y0.1O3-α (SZY-91) electrolyte was investigated. Different electrode materials, i.e., porous platinum, Sr0.5Sm0.5CoO3 (SSC-55) for the anode and nickel for the cathode were examined in order to achieve better energy performance. The electrodes had poor electrode activity when platinum was used for both the anode and the cathode, while the SSC-55 anode displayed significantly low overpotentials and the nickel cathode exhibited low overpotentials upon the introduction of an SrCe0.95Yb0.05O3-α (SCYb) interlayer. Moreover, a partial substitution of cerium for zirconium in the strontium zirconate electrolyte, i.e., SrZr0.5Ce0.4Y0.1O3-α (SZCY-541), was found to be effective for improving the current efficiency of the hydrogen evolution rate. Accordingly, the cell SSC-55|SZCY-541|SCYb|Ni exhibited much higher energy efficiency for the steam electrolysis than the Pt|SZY-91|Pt cell.