Study on electrical conductivity and phase transition in singly doped BIPBVOX (Bi 2 V 1−x Pb x O 5.5−x/2 ) solid electrolyte.

Samples of bismuth lead vanadium oxide (BIPBVOX) (Bi2V1–xPbxO5.5–x/2)singly substituted system in the composition range 0.05 ≤x≤ 0.20 were prepared by sol–gel synthesis route. Structural investigations were carried out by using a combination of differential thermal analysis (DTA) and powder X-ray diffraction (PXRD) technique. Energy dispersive X-ray spectroscopy analysis (EDXA) of doped samples was carried out to predict the sample purity and doping concentration. Transitions, α↔β, β↔γ and γ′↔γ were detected by XRD, DTA and variation in the Arrhenius plots of conductivity. The ionic conductivity was measured by AC impedance spectroscopy. The solid solutions with compositionx≤ 0.07 undergo α↔β phase transition, at 329 °C and β↔γ phase transition at 419 °C. The highly conducting γ′-phase was effectively stabilized at room temperature for compositions withx≥ 0.17 whose thermal stability increases with Pb content. At 300 °C, the highest value of conductivity 6.234 × 10−5S cm−1was obtained for compositionx= 0.15 and at 600 °C the highest value of conductivity 0.65 S cm−1is observed forx= 0.17. AC impedance plots reveal that the conductivity is mainly due to the grain contribution to oxide ion conductivity. [ABSTRACT FROM AUTHOR]