Electrical and electrochemical behaviour of Ba0.5Sr0.5Co0.8Fe0.2O3-δ : Sintering effect

Abstract

Investigations have been carried out on Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-δ (BSCF) perovskite oxides as cathode material for their use in intermediate temperature solid oxide fuel cells (IT-SOFCs).Thermal expansion coefficient (TEC), structural features, electrical conductivity,thermal analysis (weight-loss behavior), and electrochemical properties were characterized by dilatometry, X-ray diffraction (XRD), DC four-probe measurements, thermogravimetry (TG), and electrochemical impedance spectroscopy (EIS), respectively. The thermal stability of BSCF samples was found to be up to 1100 °C. Efforts have been made to study the influence of sintering profile on the microstructureand electrical conductivity of BSCF samples.The microstructure of the BSCF samples was found to be greatly influenced by the sintering parameters.The micrographs revealed that the samples sintered at lower temperatures possessed a porous structure. The electrochemical behaviour of the BSCF/Samarium doped ceria (SDC)/yttria-stabilized zirconia (YSZ)/SDC/BSCF symmetric cells has been studied as a function of sintering conditions of the BSCF electrode. The observed electrical and electrochemical behaviour of the BSCF samples has been correlated with the electrode processing parameters. The activation energies were found to be 86.94 and 104.22 kJ/mol for the electrodes sintered at 1000 and 1100 °C, respectively.