Performance and durability of metal-supported solid oxide electrolysis cells at intermediate temperatures

Metal-supported solid oxide electrolysis cells (MS-SOECs) operating at 600-700 degrees C are attractive for storage of intermittent renewable electricity from solar and wind energy due to their advantages of easy sealing and fast startup. This paper reports on the fabrication of MS-SOECs consisting of dense scandium stabilized zirconia (SSZ) electrolytes, Ce0.8Sm0.2-O2_5 (SDC)/Ni impregnated 430L/SSZ cathodes and SmBa0.5Sr0.5Co2O5+5 (SBSCO) impreg-nated SSZ anodes supported on porous 430L alloys. Such cells demonstrated excellent electrolysis performance with current densities at 650 degrees C as high as 0.73 A center dot cm_2 at 1.3 V in 50% H2O-50% H2 and 0.95 A center dot cm_2 at 1.5 V in 90% CO2-10% CO. Electrochemical impedance measurements indicated that the cell performance was largely limited by the ohmic losses for steam electrolysis and by the cathodic reduction reactions for CO2 electrolysis, espe-cially at reduced temperatures. Pronounced degradation was observed for both steam and CO2 electrolysis over the preliminary 90-h stability measurements at 600 degrees C. SEM exami-nation and EDS mapping of measured cells showed significant aggregation and coarsening of impregnated Ni particles, resulting in smaller activities for H2O and CO2 reduction re-actions. As evidenced by the almost unaltered ohmic resistances over the measurement durations, the 430L stainless steel substrates demonstrate excellent resistances against corrosions from H2O and CO2 and thus show great promise for applications in reduced -temperature MS-SOECs.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.