BICOVOX family of oxide anion conductors: chemical, electrical and structural studies

Abstract

The BICOVOX family of compounds (cobalt-doped Bi₄V₂O₁₁) has been characterised combining chemical, structural and electrical approaches. The compositional extent of the single-phase BICOVOX solid solution, stable at ambient temperature, was determined. Single-crystal and powder X-ray diffraction data, combined with density measurements, enabled us to formulate the solid solution as Bi₂(V_1–x–yCo_xBi_y)O_z. The maximum x value (0.25) is reached when y= 0.04, and the maximum y value (0.06), when x= 0.10. The evolution of the Arrhenius conductivity plots vs. x and y has been studied within the tetragonal domain. The maximum σ value is roughly independent of composition for 0.10 ⩽x⩽ 0.15 and 0 ⩽y⩽ 0.04.