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2642247 
Journal Article 
Li1.20Mn0.54Co0.13Ni0.13O2 with Different Particle Sizes as Attractive Positive Electrode Materials for Lithium-Ion Batteries: Insights into Their Structure 
Koga, H; Croguennec, L; Mannessiez, P; Menetrier, M; Weill, F; Bourgeois, L; Duttine, M; Suard, E; Delmas, C 
2012 
Yes 
Journal of Physical Chemistry C
ISSN: 1932-7447
EISSN: 1932-7455 
116 
25 
13497-13506 
WOS:000305769900005 
The effect of the synthesis temperature on the chemical composition of "Li1.20Mn0.54Co0.13Ni0.13O2" was considered using thermogravimetric analyses (TGA) and in situ X-ray diffraction (XRD) during thermal treatment. A continuous and small weight loss is observed above 800 degrees C because of Li evaporation, and the lamellar phase disappears to the benefit of a spinel-type phase formed above 940 degrees C. The layered structure is recovered upon cooling under air. "Li1.20Mn0.54Co0.13Ni0.13O2" materials synthesized at 800, 900, and 1000 degrees C show very similar compositions, structures, and electrochemical properties despite very different crystallization states. Their average structure is alpha-NaFeO2-type and described in the R (3) over barm space group, with less than 0.02 Ni2+ ions in the Li site. This peculiar composition "Li1.20Mn0.54Co0.13Ni0.13O2", with one-third of large cations (Li+, Ni2+) and two-thirds of small cations (Mn4+, Co3+) promotes the extension of the cation ordering in the slabs as revealed by the root 3a(hex) x root 3a(hex), superstructure, but without full correlation between the ordered slabs along the c(hex) stacking axis. Neutron and electron diffraction associated with NMR and Raman spectroscopies are shown to be efficient tools to get more insights into the average and local structures of these complex layered materials.