摘要：研究了LiNi0.5Co0.2Mn0.3O2的不同浓度和取代位(包括Li层和过渡金属层)对LiNi0.5Co0.2Mn0.3O2结构和电化学性能的影响。X射线衍射X射线光电子能谱和电化学实验证实LiAlO2相出现在Li1-xAlxNi0.5Co0.2Mn0.3O2样品中，有助于提高锂离子的扩散系数。而Al更倾向于在Li(Ni0.5Co0.2Mn0.3)1-yAlyO2样品中形成氧化铝固溶体，从而提高NMC的结构稳定性。与原始的LiNi0.5Co0.2Mn0.3O2相比，具有合适掺杂浓度的Al的样品能够显著提高电化学性能。本文采用高温固相法制备了LiNi0.5Co0.2Mn0.3O2锂离子电池的正极材料，并组装成电池，最后进行了电化学测试和研究。核心思想是通过掺杂金属铝离子期望对材料有所改性，基于前人在三元镍钴锰电极材料中掺杂金属离子的理念，进行进一步研究后得到以下结论：

1、发现Al以氧化铝形式固溶体固溶在LiAlxNi0.5Co0.2Mn0.3-xO2样本中后，可提高电极的结构稳定，铝的少量的掺杂与锰的比例在0.1：0.2左右，过多的铝替换锰会导致循环能力差，但是也将优于不掺杂铝离子。

2、氧化铝固溶有利于电极的结构稳定性。在LiAlxNi0.5Co0.2Mn0.3-xO2中，在一定程度上，过渡金属与铝的替代可以提高电极的循环稳定性。用低含量铝替代锂离子可以使锂离子从大体积扩散到相间，保留电极的结构完整性，可以显著提高电极的循环性能。

关键词：锂离子电池；三元正极材料；铝离子；掺杂

Learning on Modification of Ternary Battery Materials by Metal Ion  Doping

Abstract：The effects of different concentrations and substitution sites of LiNi0.5Co0.2Mn0.3O2 (including Li and transition metal layers) on the structure and electrochemical properties of iNi0.5Co0.2Mn0.3O2  were investigated. X-ray diffraction X-ray photoelectron spectroscopy and electrochemical    experiments    confirmed    that    the     LiAlO2      phase    appeared    in      the Li1-xAlxN i0.5Co0.2Mn0.3O2 sample, which helps to increase the lithium ion diffusion coefficient. However, Al tends to form AleO solid solution in the Li(Ni0.5Co0.2Mn0.3)1-yAlyO2 sample, which improves the structural stability of NMC. Compared with the original LiNi0.5Co0.2Mn0.3O2, the samples with appropriate doping concentrations of Al have significantly improved electrochemical  performance.   In  this  paper,  the   cathode   material  of  LiNi0.5Co0.2Mn0.3O2 lithium- ion battery was prepared by high temperature solid phase method and assembled. Finally, electrochemical tests and studies were performed. The core idea is  to  modify  the material through the doping of metal aluminum ions. Based on the concept of ternary nickel-cobalt-manganese electrode material doping with metal ions,the following conclusions were obtained  after  further  study:

1. It was found that  Al  solid  solution  dissolved  in  alumina  forms  solid  solution in LiAlxN i0.5Co0.2Mn0.3-xO2 sample, which can improve the structural stability of the electrode, and the ratio of aluminum doping to manganese is about 0.1:0.2. Replacement of manganese with more aluminum will result in poor cycling performance, but will also be superior to undoped  aluminum ions.

2. Aluminium oxide  solution  is conducive   to  the   electrode   structure   stability. In LiAlxN i0.5Co0.2Mn0.3-xO2, to a certain extent, the substitution of transition metal and aluminum can improve the cycle stability of the electrode. Replacing lithium ions with low levels of aluminum can diffuse lithium ions from bulk to phase, preserving the structural integrity of the electrode  and significantly  improving  the  cycling  performance   of the  electrode.