Preparation of (BaSr)<sub>0.5</sub>Sm<sub>0.5</sub>C<sub>0.8</sub>Fe<sub>0.2</sub>O<sub>3-δ</sub> and (BaSr)<sub>0.5</sub>Nd<sub>0.5</sub>C<sub>0.8</sub>Fe<sub>0.2</sub>O<sub>3-δ</sub> Cathodes for IT-SOFCs

Abstract

The development of electrochemical devices towards clean energy generation has been intensified in the last years. In this context, fuel cells, and especially intermediate temperature solid oxide fuel cells (IT-SOFC) have received much attention. Perovskite type materials of composition Ba1-xSrxCo1-yFeyO3-δ, doped or not with rare earth ions, have been quite promising because they have good ionic conductivity and operate at relatively low temperatures (500 750 °C). In this study, powders of compositions (BaSr)0.5Sm0.5Co0.8Fe0.2O3-δ (BSSCF) and (BaSr)0.5Nd0.5Co0.8Fe0.2O3-δ (BSNCF) were prepared using commercial gelatin powder as a polymerizing agent for its use as cathode. The as-prepared powders were calcined at 1000 oC and characterized by X-ray diffraction and scanning electron microscopy. Screen-printed symmetrical cells were sintered 1150 °C and studied by electrochemical impedance spectroscopy in order to assess the cathode kinetics for the oxygen reduction reaction. The best area specific resistance was found for the BSSCF cathode sintered at 1150 °C for 4 h (0.157 Ω.cm2 at 750 °C), demonstrating that this novel composition is suitable for application as SOFC cathode material. key words: Cathode, microstructure, impedance spectroscopy, IT-SOFC.