1. Structural study of Li2MnO3 by electron microscopy.
- Author
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Lei, C. H., Wen, J. G., Sardela, M., Bareño, J., Petrov, I., Kang, S.-H., and Abraham, D. P.
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CRYSTALLOGRAPHY , *X-ray diffraction , *ELECTRON microscopy , *OXIDES , *LITHIUM , *ELECTRON diffraction - Abstract
Detailed crystallographic data on high-quality Li2MnO3 material has been obtained using a combination of X-ray diffraction (XRD), selected-area electron diffraction (SAED), high-resolution electron microscopy (HREM), and 0.1 nm probe high-angle annular dark-field imaging (HAADF) in a scanning transmission electron microscope. A high-purity Li2MnO3 powder was annealed at 950 °C for 3 days to obtain predominantly defect-free grains which average size was 3.0 ± 1.5 μm. Rietveld refinement indicated that the C2/m spacegroup provided the best fit for the XRD data. Electron diffraction patterns obtained along various zone axes, on defect-free oxide particles, could be uniquely indexed to the monoclinic structure. HREM and HAADF images of defect-free grains were consistent with a Li–Mn–Mn– arrangement, i.e., lithium ordering in the transition metal planes. Low-magnification TEM images occasionally revealed stacking defects within oxide particles. HREM images of sample areas containing defects revealed a low density of stacking faults within the monoclinic sequence, resulting in a trigonal P3 1 12 local arrangement. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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