The influence of Co3O4 as a sintering aid for a series of cobalt-containing perovskite oxides on the microstructure and electrical properties have been investigated. X-ray diffraction and scanning electron microscopic results showed that well connected electrode particles with firm adhesion to the 8 mol% yttria-stabilized zirconia (YSZ) electrolyte surface were realized at a temperature free from interfacial phase reaction. Both ohmic and polarization resistances of symmetric cells by adopting YSZ electrolyte, measured by electrochemical impedance spectroscopy, were much lower than that without adding Co3O4. The peak power density of 1176 mW cm(-2) at 750 degrees C was achieved when La0.6Sr0.4Co0.2Fe0.8O3-delta + Co3O4 was selected as a representative cobaltite cathode, which is much higher than a similar fuel cell with the cathode fabricated by a conventional way. Fabrication of interlayer-free electrodes by applying Co3O4 as a sintering aid is very simple and general, applicable for a wide range of cobalt-containing electrode materials. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.