(1. 华南农业大学 理学院 生物材料研究所，广州 510642；
2. 中南大学 冶金科学与工程学院，长沙 410083)
摘 要: 采用共沉淀法制备锂离子电池掺杂型层状LiNi1/3Co1/3Mn1/3−xMxO2(M=Mg、Al、Cr)正极材料。采用X射线衍射、扫描电镜、充放电实验和交流阻抗实验对LiNi1/3Co1/3Mn1/3−xMxO2正极材料的结构、形貌、电化学性能以及动力学参数进行表征。结果表明：当掺杂量x=0.05时，Mg2+、Al3+掺杂的正极材料在2.8~4.3 V、0.1C下的首次放电比容量分别为139.2、151.6 mA∙h/g，20次循环后的容量保持率分别为98.8%和96.7%；掺杂Mg2+或Al3+均能提高LiNi1/3Co1/3Mn1/3O2的交换电流密度和锂离子扩散系数。结合实验结果和掺杂离子的离子半径和化学稳定性，解释了掺杂离子在LiNi1/3Co1/3Mn1/3O2晶格中的占位及其在充放电过程中的作用。
关键字: 锂离子电池；正极材料；层状LiNi1/3Co1/3Mn1/3O2；掺杂；改性；电化学性能
cathode materials with doping multiple components
（1. Institute of Biomaterial, College of Science, South China Agricultural University, Guangzhou 510642, China;
2. School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Layered LiNi1/3Co1/3Mn1/3−xMxO2 (M= Mg, Al, Cr) cathode materials for lithium-ion battery were synthesized by co-precipitation method. The structures, morphologies, electrochemical properties and kinetic parameters of the LiNi1/3Co1/3Mn1/3−xMxO2 cathode materials were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), charge/discharge tests and electrochemical impedance spectroscopy (EIS). The results show that the LiNi1/3Co1/3Mn1/3−xMxO2 cathode materials (M=Mg2+, Al3+; x=0.05) exhibit initial capacity of 139.2 and 151.6 mA∙h/g in the voltage range of 2.8−4.3 V, and at 0.1C rate, the capacities retain 98.8% and 96.7% after 20 cycles, respectively. Mg2+ or Al3+ doping can enhance the exchange current density and diffusion coefficient of LiNi1/3Co1/3Mn1/3−xMxO2 materials. Based on the ionic radius and chemical stability of doped metal ions, the occupation in the structure and the role of the doped metal ions during charge-discharge cycling were discussed.
Key words: lithium-ion battery; cathode materials; layered LiNi1/3Co1/3Mn1/3O2; doping; modification; electrochemical properties
