Nanocrystalline La0.6Sr0.4CoO3-delta (LSC) powder with an ultrafine microstructure is synthesized via salt-assisted spray pyrolysis and subsequently stabilized in water-based dispersions. Nanoparticulate cathode thin films of LSC and LSC-GDC (gadolinium doped ceria) nanocomposites (with 10-40 wt% of GDC) are prepared via single step spin coating on yttria stabilized zirconia (YSZ) substrates. In order to prevent the chemical reaction between the cathode and the electrolyte, a thin buffer layer of GDC is deposited using spin coating on the YSZ substrates. The electrochemical performance of the thin film cathodes is measured by impedance spectroscopy on symmetrical cells in the temperature range of 450 -650 degrees C. LSC cathode thin films (250 nm thick) with 30 wt% GDC content exhibit the lowest area specific resistance (ASR) values of 0.32, 0.78 and 2.04 Omega cm(2) in ambient air at 650, 600 and 550 degrees C, respectively. (C) 2012 Elsevier B.V. All rights reserved.