(1. 中南大学 冶金与环境学院，长沙 410083；
2. 中信大锰矿业有限责任公司，南宁 530028)
摘 要: 将前驱体Ni0.5Co0.2Mn0.3(OH)2以及前驱体和碳酸锂的混合物分别进行热处理，初步探讨其在高温热处理过程中的结构变化以及热处理方式对材料电化学性能的影响。采用X射线衍射(XRD)、热重-差热分析(TG-DSC)、扫描电镜(SEM)以及恒流充放电测试技术对合成材料物理性能和电化学进行测试和表征。结果表明：前驱体在热处理过程中，其结构经历由Me(OH)2→NiCoOOH→Mn(Ni,Co)2O4的转变过程；而前驱体与碳酸锂的混合物则经历由两相混合物→三元材料+Li2CO3→三元材料的结构转变过程；相比于单一高温平台热处理而言，采用低高温双平台热处理所合成的材料可有效降低阳离子混排，使其具有更好的电化学性能。电化学测试结果表明：在3.0~4.4 V电压范围内，其在25 ℃、0.5C下首次放电比容量为160.5 mA？h/g，60次循环后，容量保持率达98.9%。
关键字: 锂离子电池；正极材料；结构变化；电化学性能
（1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. Citic Dameng Mining Industries Limited, Nanning 530028, China）
Abstract:The Ni0.5Co0.2Mn0.3(OH)2 precursor and the mixture of Ni0.5Co0.2Mn0.3(OH)2 precursor with Li2CO3 were heat-treated, respectively, during heat-treatment, their structural change and the effects of the heat treatment method were studied. The physical and dectrochemical properties of powders were characaterized by X-ray diffraction, thermogravimetry-differential thermal analysis, scanning electron microscopy and galvanostatic charge-discharge cycling. The structural change of the precursor during the heat-treatments is as follows: Me(OH)2→NiCoOOH→Mn(Ni,Co)2O4. Comparing with single stage heating program, it is proved by the experimental results that the two-stage-heating program can be effectively used to reduce the cation mixing, thus, significantly improve the electrochemical performance of the material. LiNi0.5Co0.2Mn0.3O2 heat-treated by two-stage heating program shows a high initial discharge capacity of 160.5 mA？h/g in the voltage range of 3.0-4.4 V at 25 ℃ and 0.5C, and the capacity retention rate is 98.9% after charge-discharge cycle of 60.
Key words: lithium ion battery; cathode material; structural change; electrochemical performance
