Reaction mechanisms for 0.5Li₂MnO₃ ·0.5LiMn_0.5Ni_0.5O₂ precursor prepared by low-heating solid state reaction

Dong Li 1) , Fang Lian 1) , Xin-mei Hou 2) , and Kuo-chih Chou 1,2) 1) School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China 2) Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083, China

摘 要：Lithium-excess manganese layered oxides, which are commonly described in chemical formula 0.5Li2MnO3 ·0.5LiMn0.5Ni0.5O2 , were prepared by low-heating solid state reaction. The reaction mechanisms of synthesizing precursors, the decomposition mechanism, and intermediate materials in calcination were investigated by means of Fourier transform infrared spectroscopy （FT-IR）, X-ray diffraction （XRD）, field emission scanning electron microscopy （FESEM）, thermogravimetric analysis （TGA）, and differential scanning calorimetry （DSC）. The major diffraction patterns of 0.5Li2MnO3 ·0.5LiMn0.5Ni0.5O2 powder calcinated at 720°C for 15 h are indexed to the hexagonal structure with a space group of R 3m , and the clear splits of doublets at （006）/（102） and （108）/（110） indicate that the sample adopts a well-layered structure. FESEM images show that the size of the agglomerated particles of the sample ranges from 100 to 300 nm.

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