Durability of solid oxide electrolysis stack under dynamic load cycling for syngas production

A 6-cell solid oxide electrolysis stack was tested under H2O + CO2 co-electrolysis conditions. The cells used in the stack consisted of a nickel-yttria stabilized zirconia (Ni-YSZ) fuel electrode, YSZ electrolyte and lanthanum strontium cobaltite-gadolinium doped ceria (LSC-GDC) composite oxygen electrode. The aim of this study was to investigate the stack durability when operated under dynamic load conditions simulating a wind energy powered SOEC stack for synthesis gas production. The degradation of the stack was observed to be less than 1%/1000 h in terms of area specific resistance during the 1000 h operation. Detailed electrochemical analysis revealed a constant ohmic resistance, indicating intact contact in the stack. Only minor degradation was observed, mainly due to the fuel electrode process. The overall stack voltage degradation rate was 0.8%/1000 h.