摘要：LiNi0.8Co0.2O2具有原料资源丰富、成本低廉、电化学性能好、对环境友好等优点，它有望成为下一代锂离子电池正极材料，能应用在便携式移动电源和电动汽车动力电池等领域。

本论文采用了液相共沉淀法与固相合成相结合的方法对正极材料LiNi0.8Co0.2O2进行合成。先通过液相共沉淀法制备前驱体Ni0.8Co0.2-MOF，然后通过煅烧得到Ni0.8Co0.2O2，最后通过高温固相合成得到LiNi0.8Co0.2O2材料。对材料进行TG、XRD、SEM等表征，从XRD图谱中可以看出材料的晶体结构完整，无杂相峰且有层状结构。通过SEM图表明，材料呈球形且分布均匀。在用于正极材料的研究中，我们对材料进行了充放电测试、倍率测试、交流阻抗测试及循环伏安测试。从结果可知材料的初次放电比容量达到132.2mAh·g-1，20圈循环后的放电比容量为118.6mAh·g-1，保持率为89.7%，说明材料的循环性能很好。此外随着充放电倍率的增加，材料的比容量有所降低。材料的循环伏安曲线表面该材料的可逆性能好，循环稳定性强，与充放电测试结果相吻合。

关键词：锂离子电池；LiNi0.8Co0.2O2；正极材料；电化学性能；

Abstract：LiNi0.8Co0.2O2 has the advantages of abundant raw material resources, low cost, good electrochemical performance and environmental friendliness. It is expected to be the next generation lithium ion battery cathode material and can be used in portable mobile power and electric vehicle power battery and other fields.

In this thesis, LiNi0.8Co0.2O2 was synthesized by the method of liquid phase coprecipitation and solid phase synthesis. The precursor Ni0.8Co0.2-MOF was prepared by liquid phase coprecipitation method, then Ni0.8Co0.2O2 was obtained by calcination, and finally LiNi0.8Co0.2O2 was obtained by solid-state reaction at high temperature. The samples were characterized by TG, XRD, SEM and so on. XRD result shows that the crystal structure of the material is complete, no heterogeneous peaks and lamellar structure. The SEM shows that the material is spherical and evenly distributed. In the study of cathode materials, we carried out charge and discharge test, magnification test, AC impedance test and cyclic voltammetry. From the results, it can be seen that the specific discharge capacity of the material reaches 132.2 mAh·g-1, the discharge capacity after 20 cycles is 118.6 mAh·g-1, and the retention rate is 89.7%, which indicates that the material has good cycle performance. In addition, as the charge and discharge magnification increases, the specific capacity of the material is reduced. The cyclic voltammetric curve of the material has good reversibility of the material, strong cycle stability, consistent with the charge and discharge test results.

Keywords:  Lithium ion battery; LiNi0.8Co0.2O2; Cathode material；Electrochemical performance;

目录

第一章 绪论 1

1.1研究背景 1

1.2锂离子电池概述 1

1.2.1 锂离子电池的发展历程 1

1.2.2 锂离子电池的结构 2

1.2.3 锂离子电池的原理 3

1.3锂离子电池正极材料综述 4

1.3.1 锂离子电池对正极材料的要求 4

1.3.2 锂钴氧正极材料 4

1.3.3 锂镍氧化物 5

1.3.4 锂锰氧化物 5

1.3.5 磷酸铁锂正极材料 6

1.3.6 LiNixCoyMn1-x-yO2正极材料 7

1.4LiNi0.8Co0.2O2正极材料 7

1.4.1 LiNi0.8Co0.2O2的特性 7

1.4.2 LiNi0.8Co0.2O2的制备方法 8

1.5本论文的选题意义和研究内容 9

第二章 实验药品仪器与表征及测试原理 10

2.1 实验药品 10

2.2 实验仪器 10

2.3 材料表征分析测试方法 11

2.3.1 热重分析 11

2.3.2 X射线衍射仪（XRD） 11

2.3.3 电子扫描显微镜（SEM） 12

2.4 锂离子电池正极材料的电化学性能测试 12

2.4.1 充放电测试 12

2.4.2 倍率性能测试 13

2.4.3 循环伏安测试 13