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Long-range ordering during delithiation of LiMn2O4 cathode material

Björk, Helen ; Gustafsson, Torbjörn ; Thomas, John O. ; Lidin, Sven LU and Petříček, Václav (2003) In Journal of Materials Chemistry 13(3). p.585-589
Abstract

A single crystal of the cubic spinel LiMn2O4 was delithiated electrochemically at 4.06 V vs. Li/Li+ to probe the structural source of the inflection point at ca. 4.1 V vs. Li/Li+ in the discharge curve. The phase thus obtained was investigated by single-crystal X-ray diffraction and the structure refined. The structure is closely related to the original cubic structure, but the new space group is rhombohedral R3̄m and shows a one-dimensional modulation along the <001>r direction with wave vector q ≈ 0.75c*. The cell parameters are: a = 5.762(1) Å and c = 14.080(4), and the (3 + 1)-dimensional super space group is R3̄m(00γ). The modulated phase involves two unique Mn atoms with... (More)

A single crystal of the cubic spinel LiMn2O4 was delithiated electrochemically at 4.06 V vs. Li/Li+ to probe the structural source of the inflection point at ca. 4.1 V vs. Li/Li+ in the discharge curve. The phase thus obtained was investigated by single-crystal X-ray diffraction and the structure refined. The structure is closely related to the original cubic structure, but the new space group is rhombohedral R3̄m and shows a one-dimensional modulation along the <001>r direction with wave vector q ≈ 0.75c*. The cell parameters are: a = 5.762(1) Å and c = 14.080(4), and the (3 + 1)-dimensional super space group is R3̄m(00γ). The modulated phase involves two unique Mn atoms with coordination polyhedra which differ significantly: one has an average Mn-O distance of 2.24(1) Å, indicative of a lower oxidation state for the Mn ion; the other has an average Mn-O distance of. 1.82(2) Å, indicative of a higher oxidation state. Lithium ions appear to be extracted from the structure in a long-range-ordered two-dimensional arrangement between the cubic-close-packed oxygen layers; the manganese atoms are also arranged in charge-ordered Mn3+/Mn4+ sheets. These two features are the source of the modulation in the structure.

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author
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publishing date
type
Contribution to journal
publication status
published
in
Journal of Materials Chemistry
volume
13
issue
3
pages
5 pages
publisher
Royal Society of Chemistry
external identifiers
  • scopus:0037338505
ISSN
0959-9428
DOI
10.1039/b210265j
language
English
LU publication?
no
id
34ebbba0-37a8-4ecf-9ede-0173182642e2
date added to LUP
2019-04-08 15:33:41
date last changed
2022-01-31 18:51:58
@article{34ebbba0-37a8-4ecf-9ede-0173182642e2,
  abstract     = {{<p>A single crystal of the cubic spinel LiMn<sub>2</sub>O<sub>4</sub> was delithiated electrochemically at 4.06 V vs. Li/Li<sup>+</sup> to probe the structural source of the inflection point at ca. 4.1 V vs. Li/Li<sup>+</sup> in the discharge curve. The phase thus obtained was investigated by single-crystal X-ray diffraction and the structure refined. The structure is closely related to the original cubic structure, but the new space group is rhombohedral R3̄m and shows a one-dimensional modulation along the &lt;001&gt;<sub>r</sub> direction with wave vector q ≈ 0.75c*. The cell parameters are: a = 5.762(1) Å and c = 14.080(4), and the (3 + 1)-dimensional super space group is R3̄m(00γ). The modulated phase involves two unique Mn atoms with coordination polyhedra which differ significantly: one has an average Mn-O distance of 2.24(1) Å, indicative of a lower oxidation state for the Mn ion; the other has an average Mn-O distance of. 1.82(2) Å, indicative of a higher oxidation state. Lithium ions appear to be extracted from the structure in a long-range-ordered two-dimensional arrangement between the cubic-close-packed oxygen layers; the manganese atoms are also arranged in charge-ordered Mn<sup>3+</sup>/Mn<sup>4+</sup> sheets. These two features are the source of the modulation in the structure.</p>}},
  author       = {{Björk, Helen and Gustafsson, Torbjörn and Thomas, John O. and Lidin, Sven and Petříček, Václav}},
  issn         = {{0959-9428}},
  language     = {{eng}},
  month        = {{03}},
  number       = {{3}},
  pages        = {{585--589}},
  publisher    = {{Royal Society of Chemistry}},
  series       = {{Journal of Materials Chemistry}},
  title        = {{Long-range ordering during delithiation of LiMn<sub>2</sub>O<sub>4</sub> cathode material}},
  url          = {{http://dx.doi.org/10.1039/b210265j}},
  doi          = {{10.1039/b210265j}},
  volume       = {{13}},
  year         = {{2003}},
}