中文摘要：

通过共沉淀与固相反应法制备层状的LiNi0．45Mn0．45Co0．10O2，并利用x射线衍射（XRD）和电子扫描显微镜（SEM）测定材料的结构和形貌．在2．5～4．5V范围内，以0．1C（28mA·g^-1）放电，LiNi0．45Mn0．45Co0．10O2正极材料的起始放电容量达到167．2mAh·g^-1，但循环性能较差．当采用AIF3包覆后，材料的循环性能得到明显改善．利用电化学阻抗谱（EIS）技术探索AIF3包覆对正极材料的电化学性能改善机理，实验结果表明：AIF3包覆层能够阻止电解液对正极材料的溶解和侵蚀，稳定其层状结构，同时降低了电极界面阻抗．因此AIF3包覆技术是一种改善LiNi0．45Mn0．45Co0．10O2材料电化学性能的有效方法和工具．

英文摘要：

In this paper, layered-LiNi0.45Mn0.45Co0.10O2 was prepared by co-precipitation and solid state reaction methods. The crystal structures and morphology of the materials were investigated by X-ray diffraction （XRD） and scanning electron microscopy （SEM） techniques. The LiNio.45Mn0.45CooA002 sample delivered the initial discharge capacity of 167.2 mAh·g^-1 at 28 mA·g^-1 （0.1 C） in the range of 2.5 to 4.5 V, but the cycle-life performance was relatively bad, which could be remarkably improved by AIF3 surface coating. Electrochemical impedance spectroscopy （EIS） was used to understand the possible mechanisms of improved electrochemical properties by the AIF3 coating. The results demonstrate that these coating layers could protect the dissolution and corrosion of LiNi0.45Mn0.45Co0.10O2 cathode materials in electrolyte, stabilize its layered-structure and reduce interface impedance. Therefore, the AIF3 coating technique is an effective method and tool to improve the electrochemical properties of LiNi0.45Mn0.45Co0.10O2 cathode material.