Synthesis and phase transition of Li-Mn-O spinels with high Li/Mn ratio by thermo-decomposition of LiMnC{sub 2}O{sub 4}(Ac)
- College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083 (China) and State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China)
- College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083 (China)
- State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China)
LiMnC{sub 2}O{sub 4}(Ac) precursor in which Li{sup +} and Mn{sup 2+} were amalgamated in one molecule was prepared by solid-state reaction at room-temperature using manganese acetate, lithium hydroxide and oxalic acid as raw materials. By thermo-decomposition of LiMnC{sub 2}O{sub 4}(Ac) at various temperatures, a series of Li{sub 1+y}[Mn{sub 2-x}Li{sub x}]{sub 16d}O{sub 4} spinels were prepared with Li{sub 2}MnO{sub 3} as impurities. The structure and phase transition of these spinels were investigated by XRD, TG/DTA, average oxidation state of Mn and cyclic voltammeric techniques. Results revealed that the Li-Mn-O spinels with high Li/Mn ratio were unstable at high temperature, and the phase transition was associated with the transfer of Li{sup +} from octahedral 16c sites to 16d sites. With the sintering temperature increasing from 450 to 850 deg. C, the phase structure varied from lithiated-spinel Li{sub 2}Mn{sub 2}O{sub 4} to Li{sub 4}Mn{sub 5}O{sub 12}-like to LiMn{sub 2}O{sub 4}-like and finally to rock-salt LiMnO{sub 2}-like. A way of determining x with average oxidation state of Mn and the content of Li{sub 2}MnO{sub 3} was also demonstrated.
- OSTI ID:
- 20784962
- Journal Information:
- Journal of Solid State Chemistry, Vol. 179, Issue 4; Other Information: DOI: 10.1016/j.jssc.2005.12.039; PII: S0022-4596(06)00015-6; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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