The effects of Sr doping on the Ba-site of SmBaCo2O5+delta in term of structure characteristics, thermal expansion coefficients (TEC5), electrical properties and electrochemical performance have been investigated as cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The TEC5 of SBSC-based cathodes are calculated from 19.8 - 20.5 x 10 (6) K (1) in the temperature range of 100800 C, and the TEC values decrease with increasing Sr content. The oxygen content and the average oxidation state of cobalt increase with increasing Sr content determined by the X-ray photoelectron spectroscopy (XPS) and Thermogravimetry analysis (TGA) results. At a given temperature, the electrical conductivity values are in the order as follows: SBSC55 > SBSC73 > SBSC91. This behavior might be due to the increase in electronic hole. The electrical conductivities of SBSC55 at 600 C are distributed in the range of 660 S/cm of p(O-2)=0.01 atm to 1168 S/cm of p(O-2)=0.21 atm, indicating that the cathode can endure reducing atmosphere. SBSC55 with high electrical conductivity in p(02)=0.01 atm is ascribed to SBSC55 with stable double-perovskite structure at such low oxygen partial pressure. The SBSC55 cathode showed the highest power density of 304 mW/cm(2) at operating temperature of 700 degrees C. Based on the electrochemical properties, SBSC55 is a potential cathode for IT-SOFCs. (C) 2016 Elsevier Ltd. All rights reserved.