SrCo_1–xRu_xO_3−δ (x = 0.05, 0.1, and 0.15) Perovskites As Outperforming Cathode Material in Intermediate-Temperature Solid Oxide Fuel Cells

The performance of intermediate-temperature solid-oxide fuel cells (IT-SOFC) prominently depends on the catalytic properties of the cathode materials in the oxygen reduction reaction. With this in mind, SrCo1–xRuxO3−δ (x = 0.00, 0.05, 0.10, and 0.15) perovskite phases have been designed and prepared combining the oxygen-diffusion features of SrCoO3−δ oxide with the catalytic activity of Ru4+ ions. Additionally, the presence of Ru contributes to stabilize a tetragonal perovskite. X-ray diffraction (XRD) and in situ temperature-dependent neutron powder diffraction (NPD) experiments for x = 0.1 are used to characterize these materials. A tetragonal P4/mmm space group is observed at room temperature for SrCo1–xRuxO3−δ perovskites. The crystal structure changes into a simple-cubic perovskite unit cell above 400 °C. This can be observed from in situ NPD data. An electrical conductivity between 130 and 60 S/cm at 850 °C was obtained. Its performance as cathode materials has been investigated in single test cells, generating an exceptional power density of 1.1 W/cm2 at 850 °C with pure H2 as a fuel. Therefore, SrCo1–xRuxO3−δ (x = 0.05, 0.10, and 0.15) perovskite oxides seem to be auspicious IT-SOFC cathode candidates.