(1. 北京科技大學材料科學與工程學院，北京 100083；
2. 北京大學化學與分子工程學院，北京 100871)
摘 要: 采用液相共沉淀法制備球形摻鎂高鎳三元材料前驅(qū)體，結(jié)合高溫固相法制備了氧化硼包覆高鎳三元材料LiMg0.03(Ni0.77Co0.1 Mn0.1)O2·B2O3，對樣品物理性能、電化學性能及安全穩(wěn)定性進行分析測定，并對性能改善的機理進行分析。結(jié)果表明：通過Mg元素體相摻雜和B2O3表面包覆制備的球形高鎳三元材料LiMg0.03(Ni0.77Co0.1 Mn0.1)O2·B2O3具有良好的電化學性能和物理性能，對鋰負極初始放電容量達到181mA·h/g，對碳負極300次循環(huán)后，放電容量保持率達到92%，壓實密度達到3.9g/cm3。同時，LiMg0.03(Ni0.77Co0.1 Mn0.1)O2？B2O3具有良好的熱穩(wěn)定性和抗過充電的能力，在充電態(tài)下熱分解溫度比未摻雜和未包覆的樣品提升12℃。
關鍵字: 鋰離子電池；正極材料；三元材料；摻雜；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
