ATOMIC RESOLUTION EDS-STEM MICROSCOPY OF NANO-STRUCTURED MATERIALS (Invited Presentation)

Recently Ti-Nb-W oxides with complex crystal structures attract many researchers because of their possible candidate for all-solid Lithium battery electrodes. [1]. One of the ternary oxides of Ti and Nb has been thought to form a solid-solution crystal because their ion radii are similar. The crystal structures of these oxides were mostly studies by X-ray or neutron diffraction methods [2,3] and complementally by a high resolution transmission electron microscopy (HRTEM) method. However the method has been limited to solve problems with order disorder structures. This limitation has been overcome by recent development in STEM (Scanning TEM) combined with the advanced EDS (Energy Dispersive X-ray Spectroscopy) technology. The spatial resolution of EDS has allowed to image individual columns of atoms in a crystal, or elemental mapping of a crystal including oxygen atoms. Here we report, as an example, a clear evidence of cations ordering in a ternary metal oxide crystal of Ti₂Nb₁₀O₂₉ and other related oxides that have been intensively studied by the present author in the 1970s [4,5].

References

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