Synthesis and properties of La 0.6Sr 0.4CoO 3− δ nanopowder

Abstract

Uniform nanopowders of La 0.6Sr 0.4CoO 3− 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 La 0.6Sr 0.4CoO 3− δ powder was also optimized with proper surfactant addition. The sintered La 0.6Sr 0.4CoO 3− 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 ( R p) values of 0.17 Ω cm 2 at 700 °C and 0.07 Ω cm 2 at 750 °C in air were obtained.