Composite Oxygen Electrode Based on LSCM for Steam Electrolysis in a Proton Conducting Solid Oxide Electrolyzer

This paper presents a ceramic composite oxygen electrode (La0.75Sr0.25)(0.95)Mn0.5Cr0.5O3-delta (LSCM) - BaCe0.5Zr0.3Y0.16Zn0.04O3-delta (BCZYZ) for steam electrolysis in a proton-conducting Solid Oxide Electrolyzer (SOE) with proton conducting electrolyte BCZYZ and fuel electrode BCZYZ/Ni at 700 degrees C. AC impedance spectroscopy and I-V tests demonstrate two main processes from 0 to 2 V with 3% H2O/N-2 vs 5% H-2/Ar: reoxidation of the LSCM electrode below 1.2 V and oxidation of H2O above 1.2 V. The current density reaches 2 Acm(-2) at 2 V with electrode polarization of 0.1 Omega cm(2) and steam electrolysis shows short term stability with current efficiency of 22%. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.018212jes] All rights reserved.