Layer-structured LiMO 2 (M = Ni, Co, Mn, and dopants) is widely used as a cathode material for Li-ion secondary batteries. Ni-based LiMO 2 is advantageous with respect to energy capacity and material cost compared to conventional LiCoO 2 , but its structural and thermal stabilities decrease with increases in Ni content. As a countermeasure for these decreases, the three-component design of M comprising Ni, Co, and Mn is used universally, and small amounts of foreign elements are often added to obtain doping or surface coating effects. The relation between the composition of M and structural characteristics of LiMO 2 is investigated in this study. The features of defect generation, dopability of foreign elements, and formation of segregated secondary phases are analyzed by simulating phase diagrams based on density functional theory calculations. On this basis, a design strategy for the LiMO 2 composition is provided, with a discussion on the proper selection of doping or coating materials to improve the cathodic properties.

中文翻译：

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金属成分对锂离子电池层状正极材料结构的影响

层状结构的 LiMO 2 （M = Ni、Co、Mn 和掺杂剂）被广泛用作锂离子二次电池的正极材料。与传统的LiCoO 2 相比，Ni基LiMO 2 在能量容量和材料成本方面具有优势，但其结构和热稳定性随着Ni含量的增加而降低。作为应对这些下降的对策，普遍采用由Ni、Co和Mn组成的M的三组分设计，并且经常添加少量外来元素以获得掺杂或表面涂层效果。本研究研究了 M 的组成与 LiMO 2 的结构特征之间的关系。通过基于密度泛函理论计算的模拟相图，分析了缺陷产生、外来元素的掺杂和分离的第二相形成的特征。