Sol-gel synthesis of La0.6Sr0.4CoO3-x and Sm0.5Sr0.5CoO3-x cathode nanopowders for solid oxide fuel cells

Nano-powders of La0.6Sr0.4CoO3-x (LSC) and Sm0.5Sr0.5CoO3-x (SSC) compositions, which are being investigated as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs) with La(Sr)Ga(Mg)O3-x (LSGM) as the electrolyte, were synthesized by low-temperature sol-gel method using metal nitrates and citric acid. Thermal decomposition of the citrate gels was followed by simultaneous DSC/TGA methods. Development of phases in the gels, on heat treatments at various temperatures, was monitored by X-ray diffraction. Sol-gel powders calcined at 550-1000 degrees C consisted of a number of phases. Single perovskite phase La0.6Sr0.4CoO3-x or Sm0.5Sr0.5CoO3-x powders were obtained at 1200 degrees C and 1300 degrees C, respectively. Morphological analysis of the powders calcined at various temperatures was done by scanning electron microscopy. The average crystallite size of the powders was,similar to 15 nm after 700 degrees C calcinations and slowly increased to 70-100 nm after heat treatments at 1300-1400 degrees C. Published by Elsevier Ltd and Techna Group S.r.l.