A-deficit La0.54Sr0.44Co0.2Fe0.8O3-delta cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs) was synthesized by a citrate complexation (Pechini) route. Using La0.54Sr0.44Co0.2Fe0.8O3-delta as cathode material, a superior cell performance with the maximum power density of 309,470 and 855 mW cm(-2) at 600,650 and 700 degrees C was achieved, in contrast with the maximum power density of 266, 354 and 589 mW cm(-2) using conventional La0.6Sr0.4Co0.2Fe0.8O3-delta as cathode material at the same temperatures. The reason of this improvement was analyzed on the basis of defect chemistry. Thermal shrinkage experiment testified that the oxygen vacancies in La0.54Sr0.44Co0.2Fe0.8O3-delta are more mobile than in La0.6Sr0.4Co0.2Fe0.8O3-delta. Furthermore, theoretical calculation in terms of their composition and the shift of peak position in XRD pattern showed that the concentration of Oxygen Vacancies Of La0.54Sr0.44Co0.2Fe0.8O3-delta is higher than that of La0.6Sr0.4Co0.2Fe0.8O3-delta. Therefore, the oxygen ion conductivity via vacancies transfer mechanism is enhanced, which induces the polarization resistance of La0.54Sr0.44Co0.2Fe0.8O3-delta being decreased with a result of cell performance improved. (C) 2009 Published by Elsevier B.V.