The performance of an anode-supported solid oxide fuel cell with nanosized Ce0.8Sm0.2O1.9 (SDC) impregnated GdBaCo2O5+delta (GBCO) cathode is evaluated under various operation conditions. An SDC interlayer is applied between 8 mol% yttria-stabilized zirconia (8YSZ) electrolyte and cathode to prevent undesired chemical reaction. At 700 degrees C, the fuel cell yields a maximum power density of 790 mW cm(-2) when using simulated air as oxidant, which is promoted to 1100 mW cm(-2) in oxygen flow. The activation energies of ohmic resistance are smaller than that of bulk YSZ due to non-YSZ contribution. Electrode polarization resistance changes with fuel cell voltage while ohmic resistance nearly remains constant. The fuel cell output is mainly determined by the electrode polarization. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.