Synthesis and characterization of La_0.8Sr_0.2Co _0.8Fe_0.2O₃ nanoparticles for intermediate-low temperature solid oxide fuel cell cathodes

Nanoparticles of La_0.8Sr_0.2Co_0.8Fe _0.2O₃, which are being investigated as cathode materials for intermediate-low temperature solid oxide fuel cells, were successfully synthesized by a novel sol-gel process. The thermal decomposition behavior of gel precursor was examined using TG/DTA analysis. Development of crystalline phases in the powders calcined at various temperatures was monitored by x-ray diffraction. Single phase La_0.8Sr_0.2Co _0.8Fe_0.2O₃ could be obtained after calcining at 800°C. A small amount of impurity phase existed in the powders calcined at the temperature below 700°C. Morphological analysis of the powders calcined at various temperatures was done by scanning electron microscopy. The synthesized powders had an average particle size of 30∼90nm at 600-1100°C. The average particle size of the powders increased with increase in calcination temperature. Noticeable changes occurred at temperature above 800°C, and the coarse particles existed in the powders calcined at high temperatures.