High Temperature Co-electrolysis of Steam and CO2 in an SOC stack: Performance and Durability

In this work, co-electrolysis of steam and carbon dioxide was studied in a Topsoe Fuel Cell (TOFC®) 10-cell stack, containing three different types of Ni/yttria stabilized zirconia (YSZ) electrode supported solid oxide electrolysis cells with a footprint of 12 × 12 cm. The stack was operated at 800 °C and –0.75 A cm–2 with 60% conversion for a period of 1,000 h. One type of the cells showed no long term degradation but actually activation during the entire electrolysis period, while the other two types degraded. The performance and durability of the different cell types is discussed with respect to cell material composition and microstructure. The results of this study show that long term electrolysis is feasible without notable degradation at 800 °C and a current density of –0.75 A cm–2.