The electrochemical performances of the solid oxide fuel cells (SOFC) fabricated with Ln(0.6)Sr(0.4)Co(1-y)Fe(y)O(3-delta) (Ln=La, Nd: y = 0, 0.5) perovskite cathodes, thin yttria-stabilized zirconia (YSZ) electrolytes, and YSZ-Ni anodes by tape casting, co-firing, and screen printing are evaluated at 600-800 degrees C. Peak power densities of similar to 550 mW cm(-2) are achieved at 800 degrees C with a La0.6Sr0.4CoO3-delta (LSC) cathode that is known to have high electrical conductivity. Substitution of La by Nd (Nd0.6Sr0.4CoO3-delta) to reduce the thermal expansion coefficient (TEC) results in only a slight decrease in power density despite a lower electrical conductivity. Conversely, substitution of Fe for Co (La0.6Sr0.4Co0.5Fe0.5O3-delta or Nd0.6Sr0.4Co0.5Fe0.5O3-delta) to reduce the TEC further reduces the cell performance greatly due to a significant decrease in electrical conductivity. However, infiltration of the Fe-substituted cathodes with Ag to increase the electrical conductivity increases the cell performance while preserving the low TEC. (C) 2008 Elsevier B.V. All rights reserved.