Preparation and characterization of Pr1-xSrxFeO3 cathode material for intermediate temperature solid oxide fuel cells

A kind of cathode material of Pr1-xSrx FeO3 (x=0-0.5) for intermediate temperature solid oxide fuel cells (IT-SOFCs) was prepared by the coprecipitation method. Crystal structure, thermal expansion, electrical conductivity and electrochemical performance of the Pr1-xSrxFeO3 perovskite oxide cathodes were studied by different methods. The results revealed that Pr1-xSrxFeO3 exhibited similar orthorhombic structure from x = 0. 1 to 0.3 and took cubic structure when x = 0.4-0.5. The unit cell volume decreased and the thermal expansion coefficient (TEC) of the materials increased as the strontium content increased. When 0 < x <= 0.3, the samples exhibited good thermal expansion compatibility with YSZ electrolyte. The electrical conductivity increased with the increasing of doped strontium content. When x = 0. 3-0.5, the electrical conductivities were higher than 100 S cm(-1). The conductivity of Pr0.8Sr0.2FeO3 was 78 S cm(-1) at 800 degrees C. Compared with the La0.8Sr0.2MnO3 cathode, Pr0.8Sr0.2FeO3 showed higher polarization current density and lower polarization resistance (0.2038 Omega cm(2)). The value of I-0 for Pr0.8Sr0.2FeO3 at 800 degrees C is 123.6 mA cm(-2). It is higher than that of La0.8Sr0.2MnO3. Therefore, Pr1-xSrxFeO3 can be considered as a candidate cathode material for IT-SOFCs. (c) 2007 Elsevier B.V. All rights reserved.