Characterisation and stability of the fast ion conductor (Bi2O3)1 − x(PbO)x

Structural Properties and Thermal Stability of Bi8Pb5O17Fast Ion Conducting Phases

“…We could conjecture that the endothermic peak at 5293C is a component of the P transition and that it re#ects the fact that this transition becomes fast above 5003C. However, it has been shown by Sammes et al that depending on the temperature the system shows a di!erent defective structure (15) and that for several phases belonging to the PbO}Bi O system the majority charge carrier is the oxygen ion (16). For this reason, the thermal e!ect at 5293C could be attributed not to a macro- when this phase is just formed and not when it has aged.…”

Defect structure in δ-Bi5PbY2O11.5

“…12 Yttrium substitution for bismuth in Bi 2 O 3 is well known to yield highly conducting cubic d-type phases over a relatively large composition range [13][14][15][16][17][18] and much of this work is reviewed by Sammes et al 8 In contrast, despite the close similarity of the Bi 3+ and Pb 2+ cations, in terms of their stereochemistries (dominated by the 6s 2 lone pair) and polarizabilities, lead substitution for bismuth does not lead to the appearance of the d-type phase at low temperatures. 19 However, in ternary systems such as Bi 2 O 3 -MO x -PbO (M ¼ Ca, Y, Er and La), preservation of the d-type phase to room temperature is observed. [20][21][22][23][24] In a previous study we examined compositions in the Bi 2 O 3 -PbO-Y 2 O 3 system of general formula Bi 2.5+x Pb 0.5 YO 5.75+3x/2 (x ¼ 0, 1 and 2), which showed the d-phase structure.…”

Conductivity in lead substituted bismuth yttrate fluorites

“…Pb 2+ ions show many similarities to Bi 3+ , with similar stereochemical activity of the 6s 2 electron pairs, comparable polarizabilities (α D = 46 and 50 a.u., respectively, for the neutral atoms of Pb and Bi [23]) and adoption of similar distorted coordination environments in oxide systems. Despite these apparent similarities the cubic δ-phase in the Bi 2 O 3 -PbO binary system is only observed at elevated temperatures [24]. However, in ternary systems of the type Bi 2 O 3 -MO x -PbO (M = Ca, Y, Er and La) it has been shown that δ-type phases can be preserved to room temperature [25][26][27][28][29][30].…”