Ab InitioStructure Determination of Li₂MnO₃from X-ray Powder Diffraction Data

Abstract

The results of the structural determination of Li2MnO3 from X-ray powder diffraction data and the refinement by the Rietveld technique are presented. The Li2MnO3 structure has a monoclinic cell with space group C2/m(Z=4) and cell parameters a=4.9246 (1) and S=3.52. Such a so~'ution agrees with a single-crystal structure determination previously reported in the literature and allows other hypotheses to be rejected. plane parallel to the ac plane was underlined that the other authors did not consider.The aim of this work is to demonstrate that conventional laboratory X-ray powder diffraction data may very well be used for structure determination of compounds of low symmetry, like Li2MnO3. For such a compound, a detailed comparison with the pertinent single-crystal data is possible. The programs actually available for the treatment of powder data are sufficiently reliable, and represent a valid choice when single-crystal data cannot be obtained. Many different programs were used in each step for the ab initio structure determination, both to test the solution found and to compare different computing methods.

Synthesis, phase relation and electrical and electrochemical properties of ruthenium-substituted Li2MnO3 as a novel cathode material

“…2. All of the reflections of Li 2 MnO 3 (x = 0) were indexed in the monoclinic lattice with the space group C2/m [22,23]. The broad peaks around 20-25 • in the pattern for Li 2 MnO 3 are similar to those reported previously [24], which is attributed to the ordering of lithium and manganese in the transition metal layer.…”

Structure of Li2MnO3 with different degrees of defects

“…However, due to difficulties in modeling the experimental X-ray diffraction pattern profile and because of uncertainty in the interpretation of electron diffraction patterns, discrepancies still exist in the literature about the stacking sequence of the ordered [13][14][15][16][17][18][19]. Here, we report on the influence of the synthesis on the structure of Li 2 MnO 3 , not with the aim to compare two synthesis methods but to prepare different Li 2 MnO 3 samples showing various degrees of defects.…”

Local Structure of Layered Oxide Electrode Materials for Lithium‐Ion Batteries

“…Three different Li 2 MnO 3 structures have been reported in the literature, one rhombohedral (P3 1 12) [17] and two monoclinic (C2/m [21][22][23] and C2/c). [24] All these structures can be derived (upon Li substitution for Mn) from the rhombohedral a-NaFeO 2 structure, which in turn is structurally related to the (face centered cubic) B1-NaCl structure.…”