Structure refinement of Li{sub 4}Mn{sub 5}O{sub 12} with neutron and X-ray powder diffraction data
- National Institute of Materials and Chemical Research, Ibaraki (Japan)
- Oak Ridge National Lab., TN (United States); and others
Lithium manganese oxides have been extensively studied at the cathode materials for advanced rechargeable lithium batteries because they offer high cell voltage, good rechargeability, and a wide operating temperature range with a much lower cost compared to LiNiO{sub 2} and LiCoO{sub 2}. Well-crystallized Li{sub 4}Mn{sub 5}O{sub 12} powder was prepared by heating a eutectic mixture of lithium acetate LiOAc and manganese nitrite Mn(NO{sub 3}){sub 2} in an O{sub 2} atmosphere. The structure of Li{sub 4}Mn{sub 5}O{sub 12} crystallites was found to be cubic spinel using Rietveld refinement of both neutron and X-ray powder diffraction profiles. We confirmed that lithium ions occupy both the tetrahedral sites 8a and part of the octahedral sites 16d, but not the 16c sites in the space group Fd{bar 3}m, while all the manganese ions occupy the 16d sites. The lattice parameter was found to be sensitive to synthesis temperature as a result of the variation in manganese valence. The presence of Mn{sup 3+} leads to the formation of a stoichiometric spinel Li[Li{sub x}Mn{sub 2-x}]O{sub 4} in which x decreases from 1/3 (Li{sub 4}Mn{sub 5}O{sub 12}) to 0 (LiMn{sub 2}O{sub 4}), with concomitant formation of Li{sub 2}MnO{sub 3} depending on the synthesis conditions.
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 543091
- Journal Information:
- Journal of Solid State Chemistry, Vol. 130, Issue 1; Other Information: PBD: Apr 1997
- Country of Publication:
- United States
- Language:
- English
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