SmBaCo2O5+d (SBCO) showed the lowest observed Area Specific Resistance (ASR) value in the LnBaCo(2)O(5+d) (Ln: Pr, Nd, Sm, and Gd) oxide system for the overall temperature ranges tested. The ASR of a composite cathode (mixture of SBCO and Ce0.9Gd0.1O2-d) on a Ce0.9Gd0.1O2- d (CGO91) electrolyte decreased with respect to the CGO91 content; the percolation limit was also achieved for a 50 wt% SBCO and 50 wt% CGO91 (SBCO50) composite cathode. The ASRs of SBCO50 on the dense CGO91 electrolyte in the overall temperature range of 500-750 degrees C were relatively lower than those of SBCO50 on the CGO91 coated dense 8 mol% yttria-stabilized zirconia (8YSZ) electrolyte for the same temperature range. From 750 degrees C and for all higher temperatures tested, however, the ASRs of SBCO50 on the CGO91 coated dense 8YSZ electrolyte were lower than those of the CGO91 electrolyte. The maximum power densities of SBCO50 on the Ni- 8YSZ/8YSZ/CGO91 buffer layer were 1.034 W cm(-2) and 0.611 W cm(-2) at 800 degrees C and 700 degrees C. (C) 2017 Elsevier B.V. All rights reserved.