Abstract: An interlayer of samaria doped ceria(SDC) was prepared between Ni-SDC composite electrode and LSGM(La0.9Sr0.1Ga0.8Mg0.2O3) electrolyte using screen-printing method to improve the performance of Ni anodes. The effect of this interlayer on the performance of anode as well as the cell was studied using various electrochemical techniques. The results show that addition of the SDC interlayer reduced the anodic over-potential significantly, however, the ohmic resistance of the cell with an SDC interlayer increased, which leaded to a decrease of the power output. The electrochemical oxidation of H2 on Ni-SDC anodes was controlled by two processes, which corresponded to two arcs in the impedance spectra. The high frequency arc decreased with the addition of SDC interlayer, and could correspond to the electrochemical reaction at three-phase-boundary (TPB) or the transfer of oxygen ions from LSGM to SDC. The low frequency arc showed no dependency on the addition of SDC, and could be related to the adsorption and diffusion of H2 at the surface of electrode. The cells with an SDC interlayer showed much better stability compared with the cell using single layer anode, and the performance of the cell with Ni-SDC/SDC (1573 K) anode was higher than the cell with a single layer Ni-SDC anode after long time running.

Key words: Nickle anode, Bilayer anode, Polarization, AC impedance,