Domain boundary structures in lanthanum lithium titanates

Gao, Xiang; Fisher, Craig A. J.; Kimura, Teiichi; Ikuhara, Y.; Kuwabara, Akihide; Moriwake, Hiroki; Oki, Hideki; Tojigamori, Takeshi; Kohama, Keiichi; Ikuhara, Yuichi

doi:10.1039/c3ta13726k

Cited by 74 publications

(50 citation statements)

References 40 publications

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“…However, the two-dimensional lithium ion paths in this material are interrupted by grain boundaries, resulting in a high Rgb with σgrain boundary ≈ σtotal = 2 × 10 −5 Scm −1 (Inaguma et al, 1993;Stramare et al, 2003; et al, 2005;Gao et al, 2014;Moriwake et al, 2015). In contrast, the grain boundary resistance of garnet-like oxides is relatively low compared to other ion-conducting oxides because of the good lithium ion connection between grains, forming three dimensional lithium ion paths.…”

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confidence: 89%

Grain Boundary Analysis of the Garnet-Like Oxides Li7+X−YLa3−XAXZr2−YNbYO12 (A = Sr or Ca)

2016

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Garnet-like oxides having the formula Li7+X−YLa3−XAXZr2−YNbYO12 (A = Sr or Ca) were synthesized using a solid-state reaction, and their bulk and grain boundary resistivities were assessed by AC impedance measurements. A difference in grain boundary resistivity was identified between Sr and Ca materials, and so the grain boundaries were examined using electron probe microanalysis (EPMA). The difference in the grain boundary resistivities was attributed to the core-shell structure of the Sr-substituted samples. In contrast, the Ca-substituted materials exhibited accumulations of impurities at the grain boundaries.

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confidence: 89%

Grain Boundary Analysis of the Garnet-Like Oxides Li7+X−YLa3−XAXZr2−YNbYO12 (A = Sr or Ca)

2016

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“…In practice it is very difficult to detect such a local twinning of tilting octahedra, even using atomic-resolution HAADF/ABF imaging (Fig. 26,32 It has been shown that these crosses are a result of a number of features, including microdomains, octahedral tilting, ordering of A cations and vacancies. This is mainly due to the modulated displacements of O atoms in three dimensional space, resulting in only the average column positions being imaged (unfortunately identifying and imaging an extremely thin specimen region with only a single layer of O atoms, which would overcome this problem, is extremely difficult even with state-of-the-art equipment).…”

Section: Composition and Crystal Symmetrymentioning

confidence: 99%

Cation ordering in A-site-deficient Li-ion conducting perovskites La_(1−x)/3Li_xNbO₃

et al. 2015

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Cation-deficient perovskites exhibit complex local atomic arrangements which cannot be adequately described by average crystal structure models. By combining reciprocal-space electron diffraction analysis and direct observations of atom positions using state-of-the-art scanning transmission electron microscopy, we clarify the nature of the cation ordering within A-site-deficient perovskite single crystals of La (1Àx)/3 Li x NbO 3 (x ¼ 0 and x ¼ 0.04). Both materials are found to have complex modulated crystal structures with two types of A-cation ordering, namely a long-range layer ordering in alternate (001) p planes and a short-range (intra-domain) columnar ordering within La-rich (001) p layers. The columnar ordering (occupational modulation) produces modulated displacements of Nb and O atoms. It is also found that substitution of even a small amount of Li for La can affect significantly the columnar ordering, leading to a series of structural and microstructural changes that are likely to have a deleterious effect on the Li-ion conductivity of this material.

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“…The Li content, valence state of cations, and geometry of the oxygen octahedra in the La-rich and La-poor layers were also revealed by EELS. Furthermore, domain structures associated with the ordering between La-rich and La-poor layers were examined (Gao et al, 2014). With La blocking the Li pathways, the domain boundaries were found to impede ionic transport.…”

Section: Influence Of Grain Interior Atomic Configuration On Ionic Comentioning

confidence: 99%

Novel Solid Electrolytes for Li-Ion Batteries: A Perspective from Electron Microscopy Studies

Chi

2016

Front. Energy Res.

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Solid electrolytes can simultaneously overcome two of the most formidable challenges of Li-ion batteries: the severe safety issues and insufficient energy densities. However, before they can be implemented in actual batteries, the ionic conductivity needs to be improved and the interface with electrodes must be optimized. The prerequisite for addressing these issues is a thorough understanding of the material's behavior at the microscopic and/or the atomic level. (Scanning) transmission electron microscopy is a powerful tool for this purpose, as it can reach an ultrahigh spatial resolution. Here, we review recent electron microscopy investigations on the ion transport behavior in solid electrolytes and their interfaces. Specifically, three aspects will be highlighted: the influence of grain interior atomic configuration on ionic conductivity, the contribution of grain boundaries, and the behavior of solid electrolyte/electrode interfaces. Based on this, the perspectives for future research will be discussed.

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Domain boundary structures in lanthanum lithium titanates

Cited by 74 publications

References 40 publications

Grain Boundary Analysis of the Garnet-Like Oxides Li7+X−YLa3−XAXZr2−YNbYO12 (A = Sr or Ca)

Grain Boundary Analysis of the Garnet-Like Oxides Li7+X−YLa3−XAXZr2−YNbYO12 (A = Sr or Ca)

Cation ordering in A-site-deficient Li-ion conducting perovskites La_(1−x)/3Li_xNbO₃

Novel Solid Electrolytes for Li-Ion Batteries: A Perspective from Electron Microscopy Studies

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Domain boundary structures in lanthanum lithium titanates

Cited by 74 publications

References 40 publications

Grain Boundary Analysis of the Garnet-Like Oxides Li7+X−YLa3−XAXZr2−YNbYO12 (A = Sr or Ca)

Grain Boundary Analysis of the Garnet-Like Oxides Li7+X−YLa3−XAXZr2−YNbYO12 (A = Sr or Ca)

Cation ordering in A-site-deficient Li-ion conducting perovskites La(1−x)/3LixNbO3

Novel Solid Electrolytes for Li-Ion Batteries: A Perspective from Electron Microscopy Studies

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Cation ordering in A-site-deficient Li-ion conducting perovskites La_(1−x)/3Li_xNbO₃