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).

No abstract

Enhanced Oxide Ion Conductivity in Stabilized δ-Bi2O3. -Bi12.5Ln1.5O24.5 (Ln: La, Nd, Eu, Er, Y) materials are synthesized by reaction of stoichiometric amounts of Bi2O3, Ln2O3, and NH4ReO4 (Bi:Ln:Re = 12.5:1.5:1; air, 800°C, 36 h). The samples are characterized by powder XRD and conductivity measurements. Ln-and Re-doped δ-Bi2O3 materials exhibit low-temperature (<400°C) oxide ion conductivities that are significantly higher than previously reported for δ-Bi2O3 phases and are comparable to those of BIMEVOX (e.g. Bi 2 V 0.9 Cu 0.1 O 5.35 ) materials, with the La containing phase showing the highest conductivity. These materials offer excellent potential for low temperature applications in non-reducing conditions as ceramic oxygen generators e.g., for portable oxygen supplies. -(PUNN, R.; FETEIRA, A. M.; SINCLAIR, D. C.; GREAVES*, C.; J.

No abstract