LiMn_(2-2x)Li_xNi_xO_4(0≤X≤0.1)阴极材料的结构和电化学性能

Structural and Electrochemical Characterization of LiMn_(2-2x)Li_xNi_xO_4 (0≤x≤0.1) Cathode Materials

采用高温固相法,合成了LiMn2-2xLixNixO4(x=0.03、0.05、0.075、0.100)试样.用X射线衍射(XRD)和场发射扫描电镜(FESEM)对试样的晶体结构和形貌进行了表征.从试样的充放电性能,室温和高温下(55℃)循环性能等方面,并结合X射线吸收精细结构(X-rayabsorptionfinestructure,XAFS)所得到的试样中MnO6八面体中键长的变化分析了锂镍协同掺杂对尖晶石结构的稳定作用.实验表明:与尖晶石LiMn2O4相比,LiMn2-2xLixNixO4试样在室温和55℃时具有良好的容量保持能力,是由于Li,Ni协同掺杂对试样的结构起了稳定作用.

Lithium and nickel co-doped LiMn2-2xLixNixO4 cathode materials （x= 0, 0.03, 0.05, 0.075, 0.1） were synthesized by a high temperature solid-state reaction route. The microstructures and morphologies of the samples were characterized by X-ray powder diffraction, X-ray absorption fine structure analysis and field emitted scanning electronic microscopy. The bond lengths of the MnO6 octahedrons and the electrochemical performances in both room temperature and elevated temperature （55℃） were characterized and discussed in comparison with LiMn2O4 spinel. The result reveals that LiMn2-2xLixNixO4 samples have a good reversibility. It is suggested that the co-doping of lithium and nickel in LiMn2O4-based compounds could stabilize the spinel structure and improve the capacity retention of the cathode materials.