Electrolyte supported symmetric cells featuring La0.6Ca0.4Fe0.8Ni0.2O3 (LCFN) electrodes are studied by electrochemical impedance spectroscopy. The aim is to describe the polarization losses of this mixed ionic electronic conductor electrode at various cell operating conditions for cells sintered at different temperatures. An equivalent circuit describing the cathode polarization resistances was constructed from analyzing impedance spectra recorded at different oxygen partial pressures and temperatures. Favorable oxygen reduction reaction properties are demonstrated for the LCFN cell sintered at 750 degrees C with a polarization resistance of 0.05 Omega cm(2) at an operating temperature of 800 degrees C in pure oxygen. (C) 2013 Elsevier B.V. All rights reserved.