(1. 北京科技大学材料科学与工程学院，北京 100083；
2. 北京大学化学与分子工程学院，北京 100871)
摘 要: 采用液相共沉淀法制备球形掺镁高镍三元材料前驱体，结合高温固相法制备了氧化硼包覆高镍三元材料LiMg0.03(Ni0.77Co0.1 Mn0.1)O2·B2O3，对样品物理性能、电化学性能及安全稳定性进行分析测定，并对性能改善的机理进行分析。结果表明：通过Mg元素体相掺杂和B2O3表面包覆制备的球形高镍三元材料LiMg0.03(Ni0.77Co0.1 Mn0.1)O2·B2O3具有良好的电化学性能和物理性能，对锂负极初始放电容量达到181mA·h/g，对碳负极300次循环后，放电容量保持率达到92%，压实密度达到3.9g/cm3。同时，LiMg0.03(Ni0.77Co0.1 Mn0.1)O2？B2O3具有良好的热稳定性和抗过充电的能力，在充电态下热分解温度比未掺杂和未包覆的样品提升12℃。
关键字: 锂离子电池；正极材料；三元材料；掺杂；表面包覆
（1.School of Materials Science and Engineering,University of Science and Technology, Beijing100083, China;
2. College of Chemistry and Molecular Engineering, Peking University, Beijing 100871,China）
Abstract:Thespherical precursor doped with magnesium for high nickel ternary composites was prepared by a co-precipitation method in an aqueous solution. Then, LiMg0.03(Ni0.77Co0.1 Mn0.1)O2·B2O3 was prepared by solid state reaction method at high temperature. The physical property, electrochemical property and security stability of these samples were analyzed. The improvement mechanism was also discussed. The results show that the sample doped with magnesium and coated with boron oxide has excellent electrochemical and physical properties. The initial discharge capacity vs lithium anode is 181mA·h/g, the capacity retention rate vs graphite anode is 92% after 300 cycles, and the compact density is 3.9 g/cm3.In addition, LiMg0.03(Ni0.77Co0.1 Mn0.1)O2·B2O3 has a good thermal stability and an overcharge resistant ability, its thermal decomposition temperature in state of charge rises12℃ compared with the un-doped and uncoated sample.
Key words: lithium ion battery;cathode material; ternary composites;doping;surface coating
