Oxygen‐Vacancy Ordering at Surfaces of Lithium Manganese(III,IV) Oxide Spinel Nanoparticles

Huang, Rong; Ikuhara, Y.; Mizoguchi, Teruyasu; Findlay, Scott; Kuwabara, Akihide; Moriwake, Hiroki; Oki, Hideki; Hirayama, Tsukasa; Ikuhara, Yuichi

doi:10.1002/anie.201004638

Cited by 135 publications

(112 citation statements)

References 42 publications

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“…[14] However, for LMO aq uantitative analysis of Li with EELS is ac hallenging task, as the absorption energieso ft he Mn M-edgea nd the Li K-edge are close to each other and deconvolution of both signals is difficult. [15] Atom probe tomography (APT)i samethod with elementindependent detection efficiencyf or Li and Mn, and it is thus suitable for characterizationo fLMO. It provides 3D chemical information of solids with sub-nanometer spatial resolution by combining atomic-scale microscopy and singleatom/molecule time-of-flight spectroscopy.T he fundamental mechanism of APT is field evaporation of surface atoms from nanoscopic needle-shaped samples.A PT studies have been performed on materials such as LiCoO 2 , [16] Li 0.…”

Section: Introductionmentioning

confidence: 99%

Three‐Dimensional Microstructural Characterization of Lithium Manganese Oxide with Atom Probe Tomography

et al. 2016

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The microstructure of the active material of Li‐ion batteries has a crucial influence on local ion‐transport processes but is not yet well characterized. Atom probe tomography (APT), a method combining sub‐nanometer spatial resolution with sub‐parts‐per‐thousand chemical resolution is well suited for 3 D microstructural characterization. Herein, the results of the characterization of lithium (nickel)manganese oxides [L(N)MO] with APT are presented. Structural and chemical defects of different dimensions such as the segregation of Na impurities to grain boundaries and the appearance of a Ni‐rich foreign phase are detected. Furthermore, a lamellar microstructure correlated to fluctuations in the local Li content was observed, and its influence on Li transport in the material is discussed. In defect‐free regions, the lattice planes of LMO are reconstructed for the first time, and the high spatial resolution of APT is revealed. Thus, the results demonstrate the potential of APT for the 3 D microstructural characterization of LMO.

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Section: Introductionmentioning

confidence: 99%

Three‐Dimensional Microstructural Characterization of Lithium Manganese Oxide with Atom Probe Tomography

et al. 2016

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“…However, in ABF image, all the chemical types of atoms are visible as dark contrast including Li atoms. ABF imaging has been used to lithium ion battery and hydrogen storage materials and successfully achieved the visualization of lithium [175] and even the lightest element of hydrogen atomic column [176,177]. Therefore, it is possible to visualize all the chemical type of elements at atomic dimension.…”

Section: Imaging and Spectroscopy By Atomic-resolution Stemmentioning

confidence: 99%

Influence of Dislocations in Transition Metal Oxides on Selected Physical and Chemical Properties

et al. 2018

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Studies on dislocations in prototypic binary and ternary oxides (here TiO 2 and SrTiO 3 ) using modern TEM and scanning probe microscopy (SPM) techniques, combined with classical etch pits methods, are reviewed. Our review focuses on the important role of dislocations in the insulator-to-metal transition and for redox processes, which can be preferentially induced along dislocations using chemical and electrical gradients. It is surprising that, independently of the growth techniques, the density of dislocations in the surface layers of both prototypical oxides is high (10 9 /cm 2 for epipolished surfaces and up to 10 12 /cm 2 for the rough surface). The TEM and locally-conducting atomic force microscopy (LCAFM) measurements show that the dislocations create a network with the character of a hierarchical tree. The distribution of the dislocations in the plane of the surface is, in principle, inhomogeneous, namely a strong tendency for the bundling and creation of arrays or bands in the crystallographic <100> and <110> directions can be observed. The analysis of the core of dislocations using scanning transmission electron microscopy (STEM) techniques (such as EDX with atomic resolution, electron-energy loss spectroscopy (EELS)) shows unequivocally that the core of dislocations possesses a different crystallographic structure, electronic structure and chemical composition relative to the matrix. Because the Burgers vector of dislocations is per se invariant, the network of dislocations (with additional d 1 electrons) causes an electrical short-circuit of the matrix. This behavior is confirmed by LCAFM measurements for the stoichiometric crystals, moreover a similar dominant role of dislocations in channeling of the current after thermal reduction of the crystals or during resistive switching can be observed. In our opinion, the easy transformation of the chemical composition of the surface layers of both model oxides should be associated with the high concentration of extended defects in this region. Another important insight for the analysis of the physical properties in real oxide crystals (matrix + dislocations) comes from the studies of the nucleation of dislocations via in situ STEM indentation, namely that the dislocations can be simply nucleated under mechanical stimulus and can be easily moved at room temperature.

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“…In the imaging of oxygen atoms, the negative spherical aberration technique, developed by Urban et al, not only allows atomic resolution imaging of oxygen, but also gives the oxygen vacancy concentration in the oxide twin boundaries [26,27]. In recent years, the annular bright field (ABF) imaging technique has been successfully used to image light atoms such as nitrogen, boron [28], and lithium [29][30][31]; even the imaging of the lightest element, hydrogen, has been achieved recently [32,33]. figure 1(A)), the positions of the oxygen rows between Ti only rows are not resolved; two kinds of Ti-containing atomic columns can clearly be discriminated.…”

Section: Resultsmentioning

confidence: 99%

Direct oxygen imaging in titania nanocrystals

Lü¹,

Bruner²,

Casillas³

et al. 2012

Nanotechnology

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Recently, rutile nanotwins were synthesized using high temperature organic solvent methods, yielding two kinds of common high-quality rutile twinned nanocrystals, (101) and (301) twins, accompanied by minor rutile nanorods (Lu et al 2012 CrystEngComm 14 3120-4). In this report, the atomic structures of the rutile and anatase nanocrystals are directly resolved with no need for calculation or image simulation using atomic resolution STEM techniques. The locations of the oxygen rows in the rutile twins' boundaries are directly determined from both HAADF images and ABF images. To the best of our knowledge, this is the first time oxygen columns have been distinguished in rutile twin boundaries using HAADF and BF imaging.

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Oxygen‐Vacancy Ordering at Surfaces of Lithium Manganese(III,IV) Oxide Spinel Nanoparticles

Cited by 135 publications

References 42 publications

Three‐Dimensional Microstructural Characterization of Lithium Manganese Oxide with Atom Probe Tomography

Three‐Dimensional Microstructural Characterization of Lithium Manganese Oxide with Atom Probe Tomography

Influence of Dislocations in Transition Metal Oxides on Selected Physical and Chemical Properties

Direct oxygen imaging in titania nanocrystals

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