The Effect of Operating Temperature on Galvanostatic Operation of Solid Oxide Electrolysis Cells
Vasileios Bilalis, Bowen Li, Henrik Lund Frandsen, Ming Chen
Abstract
This study aims to investigate the effect of operating temperature on the galvanostatic operation of SOECs. Durability tests are conducted at four different temperatures but under the same current density. The analysis of the EIS data recorded during operation shows that the polarization and ohmic resistance increase considerably faster at lower temperatures. It also reveals that the main cause of degradation originates from the degradation of the Ni-YSZ electrode. Microstructure analysis reveals changes in the porosity and the %Ni atomic percentage in the active Ni-YSZ electrode layer, indicating that Ni migrates from the electrode/electrolyte interface towards the neighboring support layer. Over time, the resistance and overpotential attributed to Ni-migration exhibit linear increase. However, increase of temperature decreases their degradation rates. Overpotential thresholds for severe degradation of the Ni-YSZ electrode are identified at 750 o C and 800 o C but not at 850 o C and 900 o C due to the lower developed overpotentials.