Ni/YSZ and Ni-CeO₂/YSZ anodes prepared by impregnation for solid oxide fuel cells

In this paper, Ni/YSZ and Ni-CeO₂/YSZ anodes for a solid oxide fuel cell (SOFC) were prepared by tape casting and vacuum impregnation. By this method, the Ni content in the anode could be reduced compared to the traditional tape casting method. It was found that adding CeO₂ into the Ni/YSZ anode by a Ni(NO₃)₂ and Ce(NO₃)₃ mixed impregnation could further enhance cell performance. This was investigated in H₂ at 1073 K. XRD patterns indicated that CeO₂ and Ni were separate phases, and the CeO₂ addition could enhance the Ni dispersion on the YSZ framework surface which was observed by SEM images. It was shown that adding CeO₂ into the Ni anodes could decrease the cell polarization resistance. The maximum power density for cells with 25 wt.% Ni, 5 wt.% CeO₂-25 wt.% Ni/YSZ, or 10 wt.% CeO₂-25 wt.% Ni/YSZ anode was 230 mW cm^-2, 420 mW cm^-2 and 530 mW cm^-2, respectively, in H₂ at 1073 K. The OCV for these cells was 1.05-1.09 V, indicating that a dense electrolyte film was obtained by co-firing porous YSZ layer and dense YSZ layer.