The Effects of H2O and CO2 on Ni Migration in the Anodes of Solid Oxide Fuel Cells

One critical factor contributing to the performance degradation of solid oxide fuel cells (SOFCs) is the Ni migration in the anode. In this work, we studied and compared the influence of H2O and CO2 concentrations in the fuel gas on Ni migration using patterned anode button cells. Scanning electron microscopy (SEM) images revealed the Ni migration emerged after 24 h of constant current discharge in fuel atmospheres containing H2O and CO2. As the H2O content in the fuel increased, the rate of Ni migration increased, indicating that H2O promoted Ni migration at the anode side and contributed to the performance degradation. CO2 improved Ni migration, and the effects of H2O and CO2 on Ni migration were equivalent. Moreover, the mechanism of SOFC anode Ni migration induced by CO2 in the fuel was discussed.