Characterization and electrochemical properties of chromium-substituted pyrochlore Y2Ti2-x Cr x O7-δ

Pyrochlore oxides Y2Ti2-x Cr (x) O7-delta have been investigated as electrolyte for solid oxide fuel cell. The as-prepared powder was synthesized by sol-gel method and characterized by powder X-ray diffraction, scanning electron microscope/energy-dispersive spectroscopy, inductively coupled plasma atomic emission spectroscopy, temperature-programmed reduction and AC impedance. Y2Ti2-x Cr (x) O7-delta existed in single phase in a range of 0 < x a parts per thousand currency sign 0.8, and the cell parameters decreased as the amount of Cr dopant increased. XPS analyses indicate that the average oxidation state of Cr (n+) ions decreased with the increased Cr content. Measurements of ionic conductivities induced that the optimized performance was observed at x = 0.2 with 0.01 S/cm at 700 A degrees C due to an optimized condition of carrier concentration and carrier mobility. Y2Ti2-x Cr (x) O7-delta existed in single phase in a range of 0 < x a parts per thousand currency sign 0.8 and the optimized performance of ionic conductivity was observed at x = 0.2 with 0.01 S/cm at 700 A degrees C. [GRAPHICS] .