高等学校化学研究 ›› 2011, Vol. 27 ›› Issue (4): 669-672.
CHEN Hong1,2, WEI Ying-jin3, WANG Chun-zhong3* and CHEN Gang3
CHEN Hong1,2, WEI Ying-jin3, WANG Chun-zhong3* and CHEN Gang3
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.