Ionic conductivity in materials with a pyrochlore structure

Mandal, Balaji P.; Tyagi, A. K.

doi:10.1016/b978-0-323-90483-4.00007-6

Cited by 4 publications

(2 citation statements)

References 43 publications

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“…High radiation resistance allows pyrochlores to be used as materials for the encapsulation of nuclear waste [10,11]. Pyrochlores are also considered as promising oxygenion conductors for solid oxide fuel cells (SOFCs), so a large amount of work is aimed at studying the relationship between structure and transport properties [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Equilibrium of intrinsic and impurity point defects in Ca-doped Sm2Zr2O7

Vorotnikov,

Belyakov,

Ivanov

et al. 2024

Nanosystems: Phys. Chem. Math.

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In this work, a doping strategy was used to achieve a good conductivity in samarium zirconate which crystallizes in the pyrochlore. The production of nanopowders made it possible to form high-density ceramics with an optimal microstructure.It is shown that intrinsic and impurity defects coexist in Sm 2−x Ca x Zr 2 O 7−δ , impairing ion transport at high doping levels. Despite this, Sm 1.95 Ca 0.05 Zr 2 O 7−δ maintains low activation energy of the parent and has good ionic conductivity (10 −3 S•cm −1 at 600 • C) which is one of the largest among oxide pyrochlores. It has been shown to have a good chemical stability. The material has a thermal expansion coefficient (TEC) of 12 ppm K −1 which is higher than YSZ and provides better compatibility with electrode materials. The above makes it possible to successfully use it as a highly stable oxygen electrolyte or an intermediate thin layer at the electrolyte-electrode interface in electrochemical devices.

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Section: Introductionmentioning

confidence: 99%

Equilibrium of intrinsic and impurity point defects in Ca-doped Sm2Zr2O7

Vorotnikov,

Belyakov,

Ivanov

et al. 2024

Nanosystems: Phys. Chem. Math.

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“…Ln 2 M 2 O 7 (Ln = La-Lu, M = Ti, Zr, Hf) pyrochlores are currently thought to be a viable alternative to yttria-and scandia-stabilized ZrO 2 in its main applications, such as electrolytes for solid-oxide fuel cells [1][2][3][4][5], membranes for pure oxygen production [6] and heat-resistant materials for thermal barrier coatings [7,8]. In addition, there are some Ceramics 2023, 6 949 other active applications: e.g., catalysis [9,10], ferroelectrics [11] and luminescence [5,12,13].…”

Section: Introductionmentioning

confidence: 99%

Oxygen–Ion Conductivity, Dielectric Properties and Spectroscopic Characterization of “Stuffed” Tm2(Ti2−xTmx)O7−x/2 (x = 0, 0.1, 0.18, 0.28, 0.74) Pyrochlores

et al. 2023

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Tm2(Ti2−xTmx)O7−x/2 (x = 0, 0.1, 0.18, 0.28, 0.74) solid electrolytes have been investigated as potential electrolyte materials for solid oxygen fuel cells (SOFCs), operating in the medium temperature range (600–700 °C). The design of new oxygen-conducting materials is of importance for their possible utilization in the solid oxide fuel cells. The oxygen–ion conductivity of the Tm2(Ti2−xTmx)O7−x/2 (x = 0, 0.1, 0.18, 0.28, 0.74) “stuffed” pyrochlores ceramics was investigated by electrochemical impedance spectroscopy (two-probe AC) in dry and wet air. The synthesis of precursors via co-precipitation and the precipitate decomposition temperature have been shown to be of key importance for obtaining dense and highly conductive ceramics. At ~770 °C, the highest total conductivity, ~3.16 × 10−3 S/cm, is offered by Tm2Ti2O7. The conductivity of the fluorite-like solid solution Tm2(Ti2−xTmx)O7−x/2 (x = 0.74) is an order of magnitude lower. However, for the first time a proton contribution of ~5 × 10−5 S/cm at 600 °C has been found in Tm2(Ti2−xTmx)O7−x/2 (x = 0.74) fluorite. Until now, compositions with proton conductivity were not known for the intermediate and heavy rare earth titanates Ln2(Ti2−xLnx)O7−x/2 (Ln = Ho − Lu) systems. The use of X-ray diffraction (structural analysis with Rietveld refinement), optical spectroscopy and dielectric permittivity data allowed us to follow structural disordering in the solid solution series with increasing thulium oxide content. High and low cooling rates have been shown to have different effects on the properties of the ceramics. Slow cooling initiates’ growth of fluorite nanodomains in a pyrochlore matrix. The fabrication of such nanostructured dense composites is a promising direction in the synthesis of highly conductive solid electrolytes for SOFCs. We assume that high-temperature firing of nanophase precursors helps to obtain lightly doped “stuffed” pyrochlores, which also provide the high oxygen–ion conductivity.

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Proton transport in the novel samarium-doped layered perovskite based on BaLaInO4

Abakumova,

Tarasova

2024

Ceramics International

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Ionic conductivity in materials with a pyrochlore structure

Cited by 4 publications

References 43 publications

Equilibrium of intrinsic and impurity point defects in Ca-doped Sm2Zr2O7

Equilibrium of intrinsic and impurity point defects in Ca-doped Sm2Zr2O7

Oxygen–Ion Conductivity, Dielectric Properties and Spectroscopic Characterization of “Stuffed” Tm2(Ti2−xTmx)O7−x/2 (x = 0, 0.1, 0.18, 0.28, 0.74) Pyrochlores

Proton transport in the novel samarium-doped layered perovskite based on BaLaInO4

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