Li(Ni, Me)O2中Li/Ni原子混合占位研究的新方法及应用

A Novel Method to Study Li/Ni Atomic Mixing Occupation in Li(Ni, Me)O2 and Its Application

摘要:

介绍了作者提出的一种分析与研究锂离子电池正极活性材料Li(Ni, Me)O2 (Me=Co，Mn 或Co＋Mn) 中Li/Ni在3a/3b位混合占位的新方法，即根据Li(Ni, Me)O2的混合占位模型，借助Powder Cell 1.0计算程序模拟计算得到X射线衍射强度比与混合占位参数x的线性关系，根据实验测得的X射线衍射强度比和此线性关系方程，求得对应的混合占位参数x。把这种方法用于不同成分相关材料混合占位的理论模拟，得到5种材料衍射强度比的平方根与混合占位参数x之间的线性关系；把这些线性方程应用于实际材料Li(Ni0.6Co0.2Mn0.2)O2的合成时，获得了混合占位参数x与材料焙烧处理温度之间的关系；同时还用这种方法研究了2H-石墨/Li(Ni1/3Co1/3Mn1/3)O2电池在充放电过程中Li(Ni1/3Co1/3Mn1/3)O2晶体结构和微结构的变化。

Abstract:

A novel method proposed by the author has been explicated, which means to analyze and study the atomic occupation problem of Li and Ni on 3a and 3b sites (belong to space group) in Li(Ni,Me)O2 (Me=Co, Mn or Co＋Mn) for Li-ion battery. This method is that with the help of the mixing occupation model of Li(Ni,Me)O2 and Power Cell 1.0 simulated computing program, the linear relationship between X-ray diffraction intensity ratio and the mixing occupation parameter x were obtained, and then using the data of the ratio of integrated diffraction intensity derived by the XRD experiment, the corresponding parameter x can be got from the simulated curves directly. Based on this method, the linear relationship between the square root of diffraction intensity ratio and the mixing occupation parameter x for 5 kinds of Li(Ni,Me)O2 materials were obtained. Applying this method to the study of the atomic occupation problem in the synthesis process of Li(Ni0.6Co0.2Mn0.2)O2, the relation of the mixing occupation parameter x and baking temperature has been found. Meanwhile, this method has been also used to investigate the transformation of the crystal structure and microstructure of Li(Ni1/3Co1/3Mn1/3)O2 in a 2H-graphite/Li (Ni1/3Co1/3Mn1/3)O2 lithium ion battery during charge-discharge process.