Oxide ion transport in (Nd2−xZrx)Zr2O7+δ electrolytes by an interstitial mechanism

Shlyakhtina, A.V.; Белов, Д. А.; Knotko, A.V.; Avdeev, Maxim; Колбанев, И. В.; Vorobieva, G. A.; Karyagina, O. K.; Щербакова, Л. Г.

doi:10.1016/j.jallcom.2014.03.068

Cited by 18 publications

(20 citation statements)

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“…12,14 It may be noted that the pyrochlore-type Gd 2Ày La y Zr 2 O 7 (0 y 1) and (Nd 2Àx Zr x ) Zr 2 O 7þx/2 (x ¼ 0-0.78) solid electrolytes exhibit cubic symmetry with space group Fd 3 m with superstructure ordering. 20,21 But the present samples do not show lattice superstructure, except undoped La 2 Mo 2 O 9 .…”

Section: Resultscontrasting

confidence: 50%

“…In comparison, the cell parameter for Nd 2 (Zr 2Àx Nd x )O 7Àd increases with increasing dopant content in spite of the cubic symmetry of the pyrochlore-type materials. 21 The average lanthanum-oxygen distance (hLa-Oi) and molybdenum-oxygen distance (hMo-Oi) are calculated by averaging out distances between La/Mo and available oxygen sites (O1, O2, and O3) using disagl package in GSAS. The particular oxygen sites are indicated in parentheses.…”

Section: Resultsmentioning

confidence: 99%

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Correlation of structure and ion conduction in La2−xYxMo2O9 (0 ≤ x ≤ 0.2) oxygen ion conductors

Paul

Ghosh

2015

Journal of Applied Physics

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Articles you may be interested inSpontaneous formation of circular and vortex ferroelectric domain structure in hexagonal YMnO3 and YMn0.9Fe0.1O3 prepared by low temperature solution synthesisCorrelation of structure and ion conduction of La 2Àx Y x Mo 2 O 9 (0 x 0.2) has been investigated. The cubic symmetry with space group P2 1 3 and other structural parameters are obtained from Rietveld refinement of X-ray diffraction patterns of Y doped samples. The average lanthanum-oxygen and molybdenum-oxygen distances are obtained from the electron density contour plot. The transmission electron microscopic study confirms the cubic nature of the samples and also provides an estimate of thickness of the grain boundary. The scanning transmission electron microscope energy dispersive spectrometer mapping confirms the different orientations of grains. The composition dependence of the ionic conductivity has been correlated with that of O2 and O3 site occupancies in the [O1La 3 Mo] antitetrahedral unit. The different vibrational modes in the low frequency region due to vibration of Mo-O bands are confirmed from the analysis of FTIR and Raman spectra. The full widths at half maximum of most of the Mo-O bands are found to be independent of Y doping. Additionally, the shifts in the position of Raman bands are correlated with unit cell parameter using Gr€ uneisen constant. V C 2015 AIP Publishing LLC.

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Section: Resultscontrasting

confidence: 50%

Section: Resultsmentioning

confidence: 99%

Correlation of structure and ion conduction in La2−xYxMo2O9 (0 ≤ x ≤ 0.2) oxygen ion conductors

Paul

Ghosh

2015

Journal of Applied Physics

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“…The activation energies for conduction in dry and wet atmospheres are indicated in Table 4. It is seen that the activation energies for conduction in all of the Sm 2−x Ca x Zr 2 O 7−x/2 (x = 0, 0.05, 0.1) samples in dry air lie within the range 0.7–0.95 eV, characteristic of similar oxygen-ion-conducting systems [13,42,43,44,45]. Note that there is the Ca-doping effect above 700 °C in the pure oxygen-ion conduction region: the bulk conductivity of the Ca-doped solid solutions exceeds that of undoped Sm 2 Zr 2 O 7 .…”

Section: Resultsmentioning

confidence: 99%

Evolution of Oxygen–Ion and Proton Conductivity in Ca-Doped Ln2Zr2O7 (Ln = Sm, Gd), Located Near Pyrochlore–Fluorite Phase Boundary

et al. 2019

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Sm2−xCaxZr2O7−x/2 (x = 0, 0.05, 0.1) and Gd2−xCaxZr2O7−x/2 (x = 0.05, 0.1) mixed oxides in a pyrochlore–fluorite morphotropic phase region were prepared via the mechanical activation of oxide mixtures, followed by annealing at 1600 °C. The structure of the solid solutions was studied by X-ray diffraction and refined by the Rietveld method, water content was determined by thermogravimetry (TG), their bulk and grain-boundary conductivity was determined by impedance spectroscopy in dry and wet air (100–900 °C), and their total conductivity was measured as a function of oxygen partial pressure in the temperature range: 700–950 °C. The Sm2−xCaxZr2O7−x/2 (x = 0.05, 0.1) pyrochlore solid solutions, lying near the morphotropic phase boundary, have proton conductivity contribution both in the grain bulk and on grain boundaries below 600 °C, and pure oxygen–ion conductivity above 700 °C. The 500 °C proton conductivity contribution of Sm2−xCaxZr2O7−x/2 (x = 0.05, 0.1) is ~ 1 × 10−4 S/cm. The fluorite-like Gd2−xCaxZr2O7−x/2 (x = 0.1) solid solution has oxygen-ion bulk conductivity in entire temperature range studied, whereas proton transport contributes to its grain-boundary conductivity below 700 °C. As a result, of the morphotropic phase transition from pyrochlore Sm2−xCaxZr2O7−x/2 (x = 0.05, 0.1) to fluorite-like Gd2−xCaxZr2O7−x/2 (x = 0.05, 0.1), the bulk proton conductivity disappears and oxygen-ion conductivity decreases. The loss of bulk proton conductivity of Gd2−xCaxZr2O7−x/2 (x = 0.05, 0.1) can be associated with the fluorite structure formation. It is important to note that the degree of Ca substitution in such solid solutions (Ln2−xCax)Zr2O7−δ (Ln = Sm, Gd) is low, x < 0.1. In both series, grain-boundary conductivity usually exceeds bulk conductivity. The high grain-boundary proton conductivity of Ln2−xCaxZr2O7−x/2 (Ln = Sm, Gd; x = 0.1) is attributable to the formation of an intergranular CaZrO3-based cubic perovskite phase doped with Sm or Gd in Zr sublattice.

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“…Ceramic oxide-ion conductors are utilized as high-temperature electrochemical devices, such as solid oxide fuel cells (SOFCs), batteries, catalysts, and oxygen permeation membranes. − The oxide-ion conductors have been studied by many research groups. The main materials exhibiting high oxide-ion mobility have a limited range of structure types, such as fluorite-type, − perovskite-type, − pyrochlore-type, − K 2 NiF 4 -type, − and others. − Therefore, the discovery of new structure-type oxide-ion conductors is important for the development of innovative devices based on oxide-ion conductors. The first aim of this study was to search for Sc-containing oxide-ion conductors with a new structure by the bond-valence (BV) method.…”

Section: Introductionmentioning

confidence: 99%

Discovery of Oxide-Ion Conductors with a New Crystal Structure, BaSc_2–xA_xSi₃O_10–x/2 (A = Mg, Ca) by Screening Sc-Containing Oxides through the Bond-Valence Method and Experiments

Niwa

Yashima

2018

ACS Appl. Energy Mater.

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We have discovered oxide-ion conductors with a new crystal structure by combining the bond-valence (BV) method and experiments. In the present work, the BV-based energy barrier E b for oxide-ion migration was calculated for 123 kinds of Sc-containing oxides as a screening process. We found that the monoclinic BaGd 2 Si 3 O 10 -type barium scandium silicate BaSc 2 Si 3 O 10 has a relatively low E b , indicating that it is potentially a new oxide-ion conductor. BaSc 2 Si 3 O 10 and BaSc 1.9 A 0.1 Si 3 O 9.95 (A = Mg, Ca) were prepared by solid-state reactions. Rietveld analyses of X-ray powder diffraction data of these samples were successfully performed using the monoclinic P2 1 /m BaGd 2 Si 3 O 10 -type structure. Lattice volume V of BaSc 1.9 Mg 0.1 Si 3 O 9.95 was smaller than V of BaSc 2 Si 3 O 10 due to the substitution of smaller sized Mg 2+ for Sc 3+ , while the V of BaSc 1.9 Ca 0.1 Si 3 O 9.95 was larger than V of BaSc 2 Si 3 O 10 due to the substitution of larger sized Ca 2+ for Sc 3+ , indicating the formation of solid solutions. Electrical conductivity and ultraviolet− visible (UV−vis) diffuse reflectance measurements indicated that the dominant carrier of BaSc 2 Si 3 O 10 and BaSc 1.9 A 0.1 Si 3 O 9.95 (A = Mg, Ca) was oxide ion. Thus, BaSc 2 Si 3 O 10 and BaSc 1.9 A 0.1 Si 3 O 9.95 (A = Mg, Ca) were found to be new structure-type oxideion conductors. These materials are the first examples of pure oxide-ion conductors containing Sc as an essential element. The oxide-ion conductivity of BaSc 2 Si 3 O 10 was enhanced by doping Mg or Ca owing to the increase in the carrier (oxygen vacancy) concentration. The oxide-ion conductivities of BaSc 1.9 Mg 0.1 Si 3 O 9.95 and BaSc 1.9 Ca 0.1 Si 3 O 9.95 were approximately 19 times higher than that of BaSc 2 Si 3 O 10 at 1000 °C. The BV-based energy landscape of BaSc 2 Si 3 O 10 indicated two-or three-dimensional oxideion diffusion along the edges of Si 3 O 10 groups and/or ScO 6 octahedra.

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Oxide ion transport in (Nd2−xZrx)Zr2O7+δ electrolytes by an interstitial mechanism

Cited by 18 publications

References 25 publications

Correlation of structure and ion conduction in La2−xYxMo2O9 (0 ≤ x ≤ 0.2) oxygen ion conductors

Correlation of structure and ion conduction in La2−xYxMo2O9 (0 ≤ x ≤ 0.2) oxygen ion conductors

Evolution of Oxygen–Ion and Proton Conductivity in Ca-Doped Ln2Zr2O7 (Ln = Sm, Gd), Located Near Pyrochlore–Fluorite Phase Boundary

Discovery of Oxide-Ion Conductors with a New Crystal Structure, BaSc_2–xA_xSi₃O_10–x/2 (A = Mg, Ca) by Screening Sc-Containing Oxides through the Bond-Valence Method and Experiments

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Oxide ion transport in (Nd2−xZrx)Zr2O7+δ electrolytes by an interstitial mechanism

Cited by 18 publications

References 25 publications

Correlation of structure and ion conduction in La2−xYxMo2O9 (0 ≤ x ≤ 0.2) oxygen ion conductors

Correlation of structure and ion conduction in La2−xYxMo2O9 (0 ≤ x ≤ 0.2) oxygen ion conductors

Evolution of Oxygen–Ion and Proton Conductivity in Ca-Doped Ln2Zr2O7 (Ln = Sm, Gd), Located Near Pyrochlore–Fluorite Phase Boundary

Discovery of Oxide-Ion Conductors with a New Crystal Structure, BaSc2–xAxSi3O10–x/2 (A = Mg, Ca) by Screening Sc-Containing Oxides through the Bond-Valence Method and Experiments

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About

Discovery of Oxide-Ion Conductors with a New Crystal Structure, BaSc_2–xA_xSi₃O_10–x/2 (A = Mg, Ca) by Screening Sc-Containing Oxides through the Bond-Valence Method and Experiments