Lanthanide doped SrCoO3-delta oxides, Ln(1-x)Sr(x)CoO(3-delta)(Ln = La, Pr, Nd, Sm, and Gd), have been extensively investigated on the basis of their good ionic and electronic conductivity and high performance as IT-SOFC cathode materials. Ln(1-x)Sr(x)CoO(3-delta) (LSCs) is one of the most common materials for IT-SOFCs due to its good electrical properties and high catalytic activity, and favourable thermal stability over wide ranges of temperature and oxygen partial pressure. The role of lanthanum in LSC, however, has not been systematically studied. In this study, we systematically investigated the effect of the La in Ln(1-x)Sr(x)CoO(3-delta) cathodes on the structure, electrical properties, and electrochemical performance of the cathode. Ln(1-x)Sr(x)CoO(3-delta) is confirmed as the most suitable cathode candidate material for IT-SOFCs in terms of electrochemical performance. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.