Influence of Transition Metal Elements on Ni Migration in Solid Oxide Cell Fuel Electrodes

Abstract

In the present study, the electrochemical performance and microstructure evolutions of Ni-M (M = Fe, Cu, Mn) bimetallic fuel electrodes were investigated under SOFC and SOEC operations. Ni-Fe, Ni-Mn, Ni-Cu and pure Ni patterned fuel electrodes were sputtered on YSZ pellets. During the SOFC tests, the electrochemical performance of all Ni-M bimetallic fuel electrodes were lower than pure Ni electrode, while the degradation rates of Ni-Fe and Ni-Mn electrodes were smaller than the others. The spreading of Ni film on YSZ surface was observed for all samples, and such Ni migration was suppressed by Fe and Mn addition, whereas it was enhanced by Cu addition. During the SOEC tests, the cell performance degraded with Cu and Fe addition, but improved with Mn addition. The adhesion between Ni film and YSZ substrate was enhanced by doping Fe and Mn, which correlated well with the inhibited degradation in both fuel cell and electrolysis operations. The Ni migration phenomenon is discussed by the strength of Ni-O bond, surface tension and melting point, which are influenced by the addition of transition metal elements.