Study of phase transition and ionic conductivity changes of Cd-substituted Bi4V2O11 − δ

A new solution series of bismuth vanadate of the molecular formula Bi4CdxV2 − x O11 − δ ; 0 ≤ x ≤ 0.25 was synthesized by solid state reaction, via substitution of Cd for V in the parent compound, Bi4V2O11 − δ. The sample characterization and study of the phase transition changes were performed by using XRD, FT-IR and DSC measurements. It has been found that the ionic conducting, tetragonal γ-phase could effectively be stabilized to room temperature for x = 0.175 solid solution. Impedance spectroscopy (IS) measurements proved that the oxide ionic conductivity predominantly arises from the grain contribution. In addition, highest ionic conductivity (~ 1.30 × 10− 4 S cm− 1 at 420 °C) was observed for x = 0.20 solid solution with less pronounced thermal hysteresis.