摘要
Li0.33MnO2 cathode material was synthesized by solid state reaction which showed a monoclinic structure.In situ synchrotron diffraction showed a reversible structural transition of Li0.33MnO2 during Li＋ insertion/extraction.However,it is difficult to determine the crystal structure of lithiated Li0.33＋xMnO2 based on their poorly resolved diffraction patterns.This difficulty was successfully resolved by X-ray absorption spectroscopy（XAS） and Raman scattering which are sensitive to the short-range ordering of material lattice.Extended X-ray absorption fine structure shows the co-existence of corner-and edge-shared [MnO6] in Li0.33MnO2,whereas only edge-shared [MnO6] in lithiated Li0.96MnO2.Significantly,the differences between the Raman spectra of Li0.33MnO2 and Li0.96MnO2 indicate the phase transition of the material with Li＋ intercalation.This work shows that Li0.33MnO2 transforms to monoclinic LiMnO2 with Li＋ intercalation.This phase transformation was suggested to evolve from the migration of Mn ions.
Li0.33MnO2 cathode material was synthesized by solid state reaction which showed a monoclinic structure.In situ synchrotron diffraction showed a reversible structural transition of Li0.33MnO2 during Li＋ insertion/extraction.However,it is difficult to determine the crystal structure of lithiated Li0.33＋xMnO2 based on their poorly resolved diffraction patterns.This difficulty was successfully resolved by X-ray absorption spectroscopy（XAS） and Raman scattering which are sensitive to the short-range ordering of material lattice.Extended X-ray absorption fine structure shows the co-existence of corner-and edge-shared [MnO6] in Li0.33MnO2,whereas only edge-shared [MnO6] in lithiated Li0.96MnO2.Significantly,the differences between the Raman spectra of Li0.33MnO2 and Li0.96MnO2 indicate the phase transition of the material with Li＋ intercalation.This work shows that Li0.33MnO2 transforms to monoclinic LiMnO2 with Li＋ intercalation.This phase transformation was suggested to evolve from the migration of Mn ions.
基金
Supported by the National High-Tech Research and Development Program of China(No.2009CB220110)
the Development Program of Science and Technology of Jilin Province,China(Nos.20100557,20075007)
