Uniform nanopowders of La0.6Sr0.4CoO3-delta (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 degrees 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-delta powder was also optimized with proper surfactant addition. The sintered La0.6Sr0.4CoO3-delta bulk samples exhibited an electrical conductivity of 1867 S cm(-1) in air at 800 degrees 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 Omega cm(2) at 700 degrees C and 0.07 Omega cm(2) at 750 degrees C in air were obtained. (C) 2008 Elsevier B.V. All rights reserved.