Enhanced Oxide Ion Conductivity in Stabilized δ-Bi₂O₃

Abstract

The substitution of Re into Bi2O3 allows stabilization of the delta-Bi2O3 structure by additional substitution of any lanthanide ion to give, for example, phases of composition Bi12.5La1.5ReO24.5. Some of these phases have been found to show exceptionally high oxide ion conductivity at low temperatures, ca 10-3 S cm-1 at 300 degrees C. The phases show a significant structural difference from other delta-Bi2O3 phases previously reported, with interstitial anion sites displaced further from the ideal fluorite position, (1/4,1/4,1/4).

Bi2O3 Hierarchical Nanostructures: Controllable Synthesis, Growth Mechanism, and their Application in Photocatalysis

“…The broadening of the peaks indicates that the crystallites are small. Bismuth oxide has four main crystalline phases: monoclinic a, tetragonal b, body centered cubic g, and face-centered cubic d. [13][14][15] Among these phases, the dphase is the high-temperature phase, which usually exists at above 730 8C. In the present case, the cubic d-Bi 2 O 3 have been successfully synthesized at very low temperature.…”

Remarkably High Oxide Ion Conductivity at Low Temperature in an Ordered Fluorite‐Type Superstructure

“…Figure 1 shows the plots of the total conductivities of our two "Bi 18 Figure 1 show that the conductivities of these materials compare favorably with the best fluorite-type low-and intermediate-temperature oxide ion conductors reported in the literature so far. Between 300 and 400 8C, Bi 0.905 V 0.095 O 1.595 and Bi 0.913 V 0.087 O 1.587 show only marginally lower conductivity than the Pr-V [7] and La-Re [8] [23] in their work, [22] since they performed the measurements through an instability range (500-800 8C) identified in our study and discussed below. Our own measurements of the conductivity of Bi 0.905 V 0.095 O 1.595 on slow cooling from 800 8C gave low values which agree with those reported by Takahashi et al [22] (10 À5 -10 À3 S cm À1 in the range of 300-500 8C, see Figure S4 in the Supporting Information).…”

“…Here we report a remarkably high oxide ion conductivity at low temperatures (300-500 8C) in an ordered pseudo-cubic 3 3 3 [8,9] By contrast and unusually, our materials crystallize as stable ordered superstructures, and do not undergo phase transitions to lower symmetry and lower conductivity polymorphs. Our ab initio molecular dynamics (AIMD) simulations reveal the structural features and mechanisms which facilitate the high oxide ion mobility at low temperatures, and provide conceptual insight readily applicable to other materials and structure types.…”

“…[15,16] A common structural feature in the best d-Bi 2 O 3 -based oxide ion conductors reported so far is that doping stabilizes simple cubic structures with a % 5.5 and space group Fm " 3m. [7][8]13] By comparison, doped d-Bi 2 O 3 materials which possess long-range superstructures usually have lower conductivities. [17][18][19] Simple cubic doped materials, however, are often only metastable and convert to lower symmetry forms with significantly lower conductivities, which is a major obstacle to their practical use.…”

Comparative Study of Sb2O3(Sb2O5) and Ta2O5Doping Effects with TeO2on Electrical Properties of δ-Bi2O3

“…By using doping method with some rare earth [7,8] and transition metal (V, Nb, Ta and W) oxides [9,10] …”