Defect structure in δ-Bi5PbY2O11.5

Borowska-Centkowska, A.; Liu, Xi; Krynski, Marcin; Leszczyńska, Milena; Wróbel, W.; Małys, M.; Hull, S.; Norberg, Stefan T.; Krok, F.; Abrahams, Isaac

doi:10.1039/c9ra01233h

Cited by 8 publications

(5 citation statements)

References 68 publications

(88 reference statements)

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“…There have been many attempts to extend the temperature stability range of the δ-Bi 2 O 3 -like phase to lower temperatures (i.e., lower than 730 °C). Most of them involved solid solutions of Bi 2 O 3 with selected oxides, like Y 2 O 3 [ 70 , 71 ], WO 2 [ 72 ] or others (e.g., [ 73 , 74 ]). Though these solid solutions retained the fluorite structure to temperatures much lower than 730°C, their electrical conductivity was much lower than that of pure δ-Bi 2 O 3 .…”

Section: Extension Of Thermal Stability Range Of High-temperature Phases By Controlled Nanocrystallization Of Glassesmentioning

confidence: 99%

Towards Higher Electric Conductivity and Wider Phase Stability Range via Nanostructured Glass-Ceramics Processing

2021

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This review article presents recent studies on nanostructured glass-ceramic materials with substantially improved electrical (ionic or electronic) conductivity or with an extended temperature stability range of highly conducting high-temperature crystalline phases. Such materials were synthesized by the thermal nanocrystallization of selected electrically conducting oxide glasses. Various nanostructured systems have been described, including glass-ceramics based on ion conductive glasses (silver iodate and bismuth oxide ones) and electronic conductive glasses (vanadate-phosphate and olivine-like ones). Most systems under consideration have been studied with the practical aim of using them as electrode or solid electrolyte materials for rechargeable Li-ion, Na-ion, all-solid batteries, or solid oxide fuel cells. It has been shown that the conductivity enhancement of glass-ceramics is closely correlated with their dual microstructure, consisting of nanocrystallites (5–100 nm) confined in the glassy matrix. The disordered interfacial regions in those materials form “easy conduction” paths. It has also been shown that the glassy matrices may be a suitable environment for phases, which in bulk form are stable at high temperatures, and may exist when confined in nanograins embedded in the glassy matrix even at room temperature. Many complementary experimental techniques probing the electrical conductivity, long- and short-range structure, microstructure at the nanometer scale, or thermal transitions have been used to characterize the glass-ceramic systems under consideration. Their results have helped to explain the correlations between the microstructure and the properties of these systems.

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Section: Extension Of Thermal Stability Range Of High-temperature Phases By Controlled Nanocrystallization Of Glassesmentioning

confidence: 99%

Towards Higher Electric Conductivity and Wider Phase Stability Range via Nanostructured Glass-Ceramics Processing

2021

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“…We have previously shown that thermally induced changes in conductivity behaviour can be correlated to changes in the oxide ion vacancy distribution in other δ-Bi 2 O 3 type phases [20,38] As seen in other substituted δ-Bi 2 O 3 type phases [20,38,40], the number of tetrahedral site vacancies is significantly greater than that predicted assuming oxide ions are located exclusively within the tetrahedral sites (Table 3). As seen in the crystallographic analysis, there is significant occupancy of the 48i interstitial site, which results in an increase in the tetrahedral site vacancy concentration.…”

Section: Resultsmentioning

confidence: 79%

Stability of tungsten-doped δ-Bi3YO6

et al. 2020

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The stability of bismuth yttrium oxide doped with tungsten, Bi 3 Y 1-x W x O 6+3x/2, on annealing in air for up to 1000 h at 650 °C was investigated using a.c. impedance spectroscopy and neutron diffraction. Compositions up to x = 0.2 all show some degree of conductivity decay, but only in the case of the x = 0.10 composition is this decay relatively small and not associated with a significant structural change. Details of the short range structure of this composition were investigated by reverse Monte Carlo modelling of total neutron scattering data and again reveal no significant changes prior to and post annealing. A preference for <100> oxide ion vacancy pair alignment is found in the structure consistent with models for oxide ion conduction in these systems. Additionally, the total scattering analysis reveals a preferred vacancy association with the W 6+ cations, which adopt a four coordinate geometry in this system.

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“…This is in contrast to the situation observed in CeO 2−d , 36 and YDC, 37 where using similar methodology as well as molecular dynamics simulations, a preference for h111i ordering was noted and is more akin to the situation observed in doped bismuth oxide uorites. 53,54 While, the location of a second vacancy in the h100i direction might be thought of as energetically unfavourable due to electrostatic repulsion between the effective positive charges of the vacancies, as discussed above, the results also show evidence of preferred dopant-vacancy association and that the preference for h100i ordering over the random distribution may be associated with the minimisation of local strain around the dopant cation. It should be noted here that the RMC method of analysis does not take into account the energetics of the system, it merely models the physical total scattering data.…”

mentioning

confidence: 64%

“…As previously demonstrated, the expected ratio for randomly distributed h100i, h110i, and h111i aligned vacancy pairs is 1 : 2 : 1.3 in an ideal uorite structure. 53,54 Fig. 4b shows a plot of the partial pair correlation functions for O-O and vacancy-vacancy pairs from the nal RMC congurations for the x = 0.10 composition.…”

mentioning

confidence: 99%