Direct Preparation of Ce_0.8Sm_0.2O_1.9 Powders Oxidized With H₂O₂ for Low Temperature SOFCs Application

A novel method was developed to prepare fine doped ceria (DCO) powders directly. Ceria doped with 20 mol. % of samarium (Ce_0.8Sm_0.2O_1.9, SDC) was prepared by in-situ oxidization of hydroxide precipitates with H₂O₂ in the solutions. The resultant powder desiccated at 85°C overnight was characterized by X-ray diffraction (XRD), thermogravimetry /differential thermal analysis (TG/DTA), and transmission electron microscopy (TEM). The XRD pattern showed that the as-dried SDC powder is single phase with a cubic fluorite structure like that of pure CeO₂. An anode-supported SOFC was also fabricated based on SDC and 20wt. % (62mol. %Li₂CO₃–38 mol. %K₂CO₃) composite electrolyte, LiNiO₂ as cathode and NiO as anode, by cold pressing. Using hydrogen as the fuel and air as the oxidant, the I-V and I-P characteristics exhibit excellent performances and the maximum power densities are about 696, 469, 377 and 240 mWcm⁻² at 650, 600, 550 and 500°C, respectively.