Novel Anion-Doped Cathode Material SrFe_1–xSi_xO_3−δF_y for Intermediate-Temperature Solid Oxide Fuel Cells

Abstract

SrFe 1−x Si x O 3−δ F y cathode materials (x = 0.05, 0.1, 0.15; y = 0, 0.1, 0.5) were prepared via a solid-state method. X-ray diffraction results show that the synthesized F doping samples were perovskite structure. X-ray photoelectron spectroscopy findings show that F − anions were doped into SrFe 1−x Si x O 3−δ . Transmission electron microscopy and energy-dispersive spectroscopy were performed to analyze the microstructure and element distribution in the materials, respectively. Double-layer composite cathode symmetric cells were prepared through a screen printing method. Scanning electron microscopy images revealed that the doublelayer composite cathode adhered well to the electrolyte. The doping with F − can increase the coefficient of thermal expansion of SrFe 1−x Si x O 3−δ . The electrochemical impedance spectroscopy results indicate that the oxygen transport capacity of the SrFe 0.95 Si 0.05 O 3−δ material can be improved by doping with F − , but such a method can decrease the oxygen transport capacity of SrFe 0.9 Si 0.1 O 3−δ . At 800 °C, the peak power density of the single cell supported by an anode and SrFe 0.9 Si 0.1 O 3−δ F 0.1 as the cathode reached 388.91 mW/cm 2 . Thus, the incorporation of F − into SrFe 1−x Si x O 3−δ cathode materials can improve their electrochemical performance and enable their application as cathode materials for solid-oxide fuel cells.