Synthesis and properties of Ni–SDC cermets for IT–SOFC anode by co-precipitation

Ni–Samaria-doped ceria (SDC) cermets have been prepared using a chemical co-precipitation process with Ni(NO3)2, Sm(NO3)3 and Ce(NO3)3 as precursors and (NH4)2CO3 as mineralizer. The co-precipitates were fired at 600, 700 and 800 °C for 2 h, respectively, resulting in powders, which consist of two phases, the cubic NiO and fluorite structure ceria as confirmed with X-ray diffraction identification. The powder was observed with transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The powders were fine with surface area of 23–51 m2/g, and an average agglomerate particle size of 0.23–0.36 μm. The powder was sintered to porous NiO–SDC cermets, which were subsequently reduced to Ni–SDC cermets with porosity of about 30–40%. The Ni–SDC cermets exhibit metallic behavior over the temperature from 500 to 800 °C, as measured with a DC four-probe technique in H2. The Ni–SDC cermets with high electrical conductivity appear to be compatible with the electrolyte (SDC) for intermediate temperature solid oxide fuel cell (IT-SOFC) application.