BICOVOX FAMILY OF OXIDE ANION CONDUCTORS - CHEMICAL, ELECTRICAL AND STRUCTURAL STUDIES

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 Bi-2(V1-x-yCoxBiy)O-2. 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 sigma Value is roughly independent of composition for 0.10 less than or equal to x less than or equal to 0.15 and 0 less than or equal to y less than or equal to 0.04.