锂离子电池正极材料LiMnO_2的掺杂及其电化学性能

Doping of Layered LiMnO_2 as Cathode Materials for Lithium-Ion Batteries and Their Electrochemical Properties

采用水热法合成了用于锂离子电池正极材料的LiMxMn1-xO2(M=Mg,Y,Zr)化合物.采用X射线衍射(XRD)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)等手段对材料的晶体结构和形貌进行了表征,材料的电化学性能通过恒流充放电和交流阻抗谱(EIS)进行测试,分析了掺杂元素在改善材料性能中的作用.结果表明,掺杂后的LiMxMn1-xO2正极材料循环性能优于未经掺杂的材料.其中以掺杂钇的Li0.99Mn0.979Y0.021O2正极材料循环性能最佳,在室温下,充放电电流密度为50mA·g-1时,60次循环后放电容量为226.3mAh·g-1.

Hydrothermal methods were used to prepare doped LiMxMn1-xO2（M=Mg,Y,Zr） as cathode materials for lithium-ion batteries. The structure and morphology of the as-prepared cathode materials were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM） and X-ray photoelectron spectroscopy （XPS）. The effects of ion doping on the performance of orthorhombic materials was analyzed in terms of their crystal structure, charge- discharge curves, cycle performance and electrochemical impedance spectroscopy （EIS）. Results show that the doped materials had better cycle performance. In particular, the discharge capacity of Li0.99Mn0.979Y0.021O2 remains 226.3 mAh. g-1 after 60 cycles with a current density of 50 mA· g-1 at room temperature.