Highly active Sm0.2Ce0.8O1.9 powders of very low apparent density derived from mixed cerium sources

Low apparent density Sm0.2Ce0.8O1.9 (SDC) powders of different morphology and microstructure are derived from a glycine–nitrate process using Ce(NO3)3 and Ce(NH4)2(NO3)6 as the cerium sources. When the molar ratio of the two cerium precursors is around 1:1, the derived SDC powders can be readily sintered to high density, exhibiting the highest conductivities (∼0.084 and ∼0.020 S cm−1 at 800 and 600 °C, respectively) with an activation energy of ∼0.70 eV. When the molar ratio of Ce(NO3)3 to Ce(NH4)2(NO3)6 was adjusted to 3:1, the derived SDC powders have the lowest apparent density (36.0 ± 0.5 mg cm−3), best suited for preparation of dense, thin-film SDC electrolyte membranes on porous anode substrates, a critical step toward low-cost fabrication of high-performance SOFCs.

► Low apparent density SDC powders are derived from a GNP using mixed cerium precursors. ► High density and conductivity (∼0.020 S cm−1 at 600 °C) SDC thin films are fabricated. ► Very high peak power density (0.725 W cm−2 at 600 °C) is demonstrated.