ChemInform Abstract: 3D Transition Metal Ordering and Rietveld Stacking Fault Quantification in the New Oxychalcogenides La2O2Cu2—4xCd2xSe2 .

Ainsworth, Chris M.; Lewis, James W.; Wang, Chun‐Hai; Coelho, A. A.; Johnston, Hannah E.; Brand, Helen E. A.; Evans, John S. O.

doi:10.1002/chin.201630002

Cited by 6 publications

(8 citation statements)

References 1 publication

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“…The layer constitution was derived from the crystal structure of Li 3 ErI 6 . 39 For the refinement, a recursive supercell approach implemented into TOPAS 61,62 was used to calculate PXRD patterns from randomly created stacks of layers and average them. Therefore, the monoclinic unit cell was transformed into a pseudoorthorhombic cell with space group P1 according to a procedure published elsewhere.…”

Section: + → 3lix Hoxmentioning

confidence: 99%

Enhancement of Superionic Conductivity by Halide Substitution in Strongly Stacking Faulted Li₃HoBr_6–xI_x Phases

et al. 2022

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Ternary lithium halide-based solid electrolytes have attracted broad scientific interest due to their high ionic conductivities in conjunction with good electrochemical stabilities against high-voltage cathode materials. Here, we analyze the structure of the rare earth halide solid solution series Li3HoBr6–x I x and quantify structural defects such as intralayer cation disorder and stacking faults. Almost all members of the solid solution series show strong stacking fault disorder, whereas the intralayer cation disorder systematically increases with increasing iodide content. The substitution of bromide by iodide in Li3HoBr6–x I x leads to an increasing lattice softness and therefore to a higher ionic conductivity and to a lower activation energy. This is counteracted by the increased cation disorder, which also has a strong influence on the ionic conductivity of the solid solution series. Thus, a decrease in ionic conductivity by one order of magnitude is observed when the iodine content exceeds an optimum value. Stacking faults on the other hand do not have a significant impact on the ionic conductivity as the connectivity between neighboring lithium halide octahedra and hence the energy landscape of their migration pathways is not affected for equivalent stacking vectors. The competing factors above give rise to an optimum ionic conductivity at x ≈ 3 with 2.7 × 10–3 S cm–1 at 20 °C and an activation energy of 0.21 eV. While thermal annealing reduces the structural disorder of Li3HoBr6–x I x , the self-healing properties are significantly impeded by mechanical sample treatment, demonstrating the complex interplay between thermal and mechanical effects on the microstructure and, hence, ionic conductivity of layered superionic conductors.

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Section: + → 3lix Hoxmentioning

confidence: 99%

Enhancement of Superionic Conductivity by Halide Substitution in Strongly Stacking Faulted Li₃HoBr_6–xI_x Phases

et al. 2022

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“…49 Additionally, the 003 basal reflection is split into two overlapping Bragg peaks, suggesting a modulation of the interlayer distance, likely by interstratification effects. Thus, by applying a supercell approach, 50,51 the microstructure of the stacking-faulted dry Li-TS was approximated by a combination of stacking faults and turbostratic disorder as summarized in the following.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Fast Water-Assisted Lithium Ion Conduction in Restacked Lithium Tin Sulfide Nanosheets

et al. 2021

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While two-dimensional (2D) materials may preserve some intrinsic properties of the corresponding layered bulk material, new characteristics arise from their pronounced anisotropy or confinement effects. Recently, exceptionally high ionic conductivities were discovered in 2D materials such as graphene oxide and vermiculite. Here, we report on the water-assisted fast conduction of lithium ions in restacked lithium tin sulfide nanosheets. Li0.8Sn0.8S2 exfoliates spontaneously in water and can be restacked into homogeneous films in which the lithium content is decreased, and a partial substitution of sulfur with hydroxyl groups takes place. Using a recursive supercell refinement approach in reciprocal space along with real-space pair distribution function analysis, we describe restacked lithium tin sulfide as a partially turbostratically disordered material composed of lithium-containing and lithium-depleted layers. In humid air, the material takes up multiple layers of water that coordinate lithium ions in the space between the layers, increasing the stacking distance and screening the interaction between lithium ions and the anionic layers. This results in a 1000-fold increase in ionic conductivity up to 47 mS cm–1 at high humidities. Orientation-dependent impedance spectroscopy suggests a facile in-plane conduction and a hindered out-of-plane conduction. Pulsed field gradient nuclear magnetic resonance spectroscopy reveals a fast, simultaneous diffusion of a majority and a minority species for both 7Li and 1H, suggesting water-assisted lithium diffusion to be at play. This study enlarges the family of nanosheet-based ionic conductors and helps to rationalize the transport mechanism of lithium ions enabled by hydration in a nanoconfined 2D space.

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“…This also indicates that correctly modeling stacking disorder is critical for accurate determination of the intermediate-and long-range structure. While stacking fault analysis has been routinely carried out for various bulk layered compounds using powder XRD data, 29,32,66 only a few examples can be found for heavily stacking faulted small nanoparticles. 67−69 The major advantage for stacking fault analysis (in reciprocal space) for bulk materials lies in the nature of one-dimensional disorder of stacking faults (perfect periodicity within the basal plane), which enables the analytical calculation of the layer structure factors (F hk0 ) when the faults are randomly distributed in the relatively large bulk particles.…”

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confidence: 99%

Large-Scale Synthesis and Comprehensive Structure Study of δ-MnO₂

Liu

et al. 2018

Inorg. Chem.

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Layered δ-MnO (birnessites) are ubiquitous in nature and have also been reported to work as promising water oxidation catalysts or rechargeable alkali-ion battery cathodes when fabricated under appropriate conditions. Although tremendous effort has been spent on resolving the structure of natural/synthetic layered δ-MnO in the last few decades, no conclusive result has been reached. In this Article, we report an environmentally friendly route to synthesizing homogeneous Cu-rich layered δ-MnO nanoflowers in large scale. The local and average structure of synthetic Cu-rich layered δ-MnO has been successfully resolved from combined Mn/Cu K-edge extended X-ray fine structure spectroscopy and X-ray and neutron total scattering analysis. It is found that appreciable amounts (∼8%) of Mn vacancies are present in the MnO layer and Cu occupies the interlayer sites above/below the vacant Mn sites. Effective hydrogen bonding among the interlayer water molecules and adjacent layer O ions has also been observed for the first time. These hydrogen bonds are found to play the key role in maintaining the intermediate and long-range stacking coherence of MnO layers. Quantitative analysis of the turbostratic stacking disorder in this compound was achieved using a supercell approach coupled with anisotropic particle-size-effect modeling. The present method is expected to be generally applicable to the structural study of other technologically important nanomaterials.

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ChemInform Abstract: 3D Transition Metal Ordering and Rietveld Stacking Fault Quantification in the New Oxychalcogenides La₂O₂Cu_2—4xCd_2xSe₂.

Abstract: Polycrystalline samples of La2O2Cu2‐4xCd2xSe2 (x = 0—0.5) are prepared by solid state reaction of La2O3 and the elements in the presence of Al powder as O2 getter (Al2O3 crucible in evacuated silica tubes, 1100 °C, 12 h).

Cited by 6 publications

References 1 publication

Enhancement of Superionic Conductivity by Halide Substitution in Strongly Stacking Faulted Li₃HoBr_6–xI_x Phases

Enhancement of Superionic Conductivity by Halide Substitution in Strongly Stacking Faulted Li₃HoBr_6–xI_x Phases

Fast Water-Assisted Lithium Ion Conduction in Restacked Lithium Tin Sulfide Nanosheets

Large-Scale Synthesis and Comprehensive Structure Study of δ-MnO₂

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ChemInform Abstract: 3D Transition Metal Ordering and Rietveld Stacking Fault Quantification in the New Oxychalcogenides La2O2Cu2—4xCd2xSe2 .

Abstract: Polycrystalline samples of La2O2Cu2‐4xCd2xSe2 (x = 0—0.5) are prepared by solid state reaction of La2O3 and the elements in the presence of Al powder as O2 getter (Al2O3 crucible in evacuated silica tubes, 1100 °C, 12 h).

Cited by 6 publications

References 1 publication

Enhancement of Superionic Conductivity by Halide Substitution in Strongly Stacking Faulted Li3HoBr6–xIx Phases

Enhancement of Superionic Conductivity by Halide Substitution in Strongly Stacking Faulted Li3HoBr6–xIx Phases

Fast Water-Assisted Lithium Ion Conduction in Restacked Lithium Tin Sulfide Nanosheets

Large-Scale Synthesis and Comprehensive Structure Study of δ-MnO2

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ChemInform Abstract: 3D Transition Metal Ordering and Rietveld Stacking Fault Quantification in the New Oxychalcogenides La₂O₂Cu_2—4xCd_2xSe₂.

Enhancement of Superionic Conductivity by Halide Substitution in Strongly Stacking Faulted Li₃HoBr_6–xI_x Phases

Enhancement of Superionic Conductivity by Halide Substitution in Strongly Stacking Faulted Li₃HoBr_6–xI_x Phases

Large-Scale Synthesis and Comprehensive Structure Study of δ-MnO₂