Electrochemical and chemical stability performance improvement of Ba_0.5Sr_0.5Fe_0.91Al_0.09O_3-δ cathode for IT-SOFC through the introduction of a GDC interlayer

In order to enhance the electrochemical performance of solid oxide fuel cells (SOFCs), a Gd_0.2Ce_0.8O_2-δ (GDC) interlayer was introduced to Ba_0.5Sr_0.5Fe_0.91Al_0.09O_3-δ (BSFA) cathode. The chemical stability and microstructure of the samples were characterized by X-Ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical performance was tested by impedance spectroscopy. The results show that BSFA cathode is chemically and mechanically stable with the existence of a GDC interlayer. The polarization resistance of BSFA cathode with a GDC interlayer was 0.3009 Ω cm² and the maximum power density (P_max) of an anode supported single cell reached 1321 mW cm^-2 at 750 °C. Furthermore, a BSFA-GDC composite cathode was prepared and presented excellent performance with the P_max of 1957 mW cm^-2 at 750 °C, providing a feasible choice for IT-SOFC cathodes.