Synthesis and properties of La0.6Sr0.4CoO3−δ nanopowder

Uniform nanopowders of La0.6Sr0.4CoO3−δ (LSC) were synthesized by the combined citrate–EDTA method. The precursor solution was prepared from nitrates of the constituent metal ion, citric acid and EDTA with a pH value controlled by ammonia. The obtained product was characterized by TG/DTA, XRD, SEM, and BET measurements. The single perovskite phase could form completely after sintering at the temperature of 900 °C. There was no significant effect of the precursor solution pH value on the perovskite phase formation temperature; however, LSC powders prepared from the precursors with different pH values showed specific shapes. The morphology of La0.6Sr0.4CoO3−δ powder was also optimized with proper surfactant addition. The sintered La0.6Sr0.4CoO3−δ bulk samples exhibited an electrical conductivity of 1867 S cm−1 in air at 800 °C. The impedance spectra of a symmetric LSC cathode on a GDC electrolyte substrate were measured and polarization resistance (Rp) values of 0.17 Ω cm2 at 700 °C and 0.07 Ω cm2 at 750 °C in air were obtained.