Research Progress on the Long-term Stability of Ni-YSZ Fuel Electrodes in Solid Oxide Cells

Solid oxide cells (SOCs) are promising energy conversion technology for carbon-neutral direction. Although impressive progress has been made in developing mixed ionic and electronic conductor (MIEC) composite electrodes and perovskite fuel electrodes, Ni-YSZ is the best option for commercial application, because of its excellent catalytic effect for both hydrogen oxidation reaction (HOR) in SOFC and hydrogen evolution reaction (HER) in SOEC. However, the degradation of Ni-YSZ electrodes is still an important issue restricting the development of SOCs. Ni-YSZ electrode materials are briefly introduced and the typical phenomena related to Ni-YSZ electrode degradation in SOFC and SOEC are summarized. Also, the reason of degradation of the Ni-YSZ electrode is examined, based on which improvement strategies are proposed. Finally, an outlook on the optimization for the long-term stability of Ni-YSZ electrodes is presented.