Cobalt oxides coated commercial Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ as high performance cathode for low-temperature SOFCs

Highlights: • A novel solution coating method was used to modify the commercial BSCF. • Electrical conductivity of modified BSCF with 5–10 wt% CoO_x was enhanced by 5–27%. • Peak power density of anode-supported fuel cell was nearly enhanced by 100%. • A CoO_x promoted ORR mechanism was proposed. • The applied modification method of perovskite has great potential in exploring new functional cathodes for advanced LTSOFCs. - Abstract: In order to improve the catalytic activity of commercial Ba_0.5S_r0.5Co_0.8Fe_0.2O_3-δ (BSCF) for low-temperature solid oxide fuel cells (LTSOFC) (300–600 °C), CoO_x has been used to modify the commercial BSCF through a solution coating approach. Phase and morphology of samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy-dispersive spectrometry (EDS), respectively. BSCF with 10 wt% CoO_x exhibited an improved conductivity of 44 S/cm, and achieved a peak power density of 463 mW/cm² at 550 °C for LTSOFC, which is a 100% enhancement than that with the BSCF cathode. The cathode oxygen reduction reaction (ORR) promoted by CoO_x and enhanced device performance mechanism have been proposed. This work provides a new way for the exploitation of high effective cathode materials for LTSOFCs.