Li2YO3（Y=Ti、Zr和Mn）壳层调控高镍三元NMC811正极材料结构有序度及储锂性能基础研究

高镍三元层状LiNi0.8Mn0.1Co0.1O2（NMC811）材料被认为是极具应用前景的动力锂离子电池正极材料。我们前期研究表明，由于高的Ni含量和低的Co、Mn含量，最优化制备的NMC811材料层状结构内依然存在着较高程度的阳离子混排和熔岩型氧化物杂相以及锂基碱性物质在材料表面的残留，均直接与其烧结过程中的锂盐反应密切相关，严重影响其储锂循环和倍率性能。基于已有的研究积累，可通过调控高镍三元材料烧结过程中的锂源反应，达到优化其层状结构并提升储锂性能的目的。本项目拟结合预烧处理和Li2YO3（Y=Ti、Zr和Mn）壳层的可控构筑，来调控NMC811材料烧结过程中的锂盐反应，获得具有高层状结构有序度和低残碱物质含量的高镍三元正极材料。本项目将揭示Li2YO3壳层调控锂盐反应的机理，以及其与NMC811材料储锂电化学性能的构效关系，为优化高镍三元材料层状结构和界面电化学行为提供科学依据。

Ternary Ni-rich layered LiNi0.8Mn0.1Co0.1O2 (NMC811) has been considered as a promising cathode candidate for high-power lithium ion batteries. Based on our previous work, NMC811 material even obtained in optimal preparation still has a high degree of cation mixing and the formation of impure rock-salt oxides within the layered structure along with residual lithium-based alkaline byproducts at its surface, leading to poor cycling and high-rate performances. These above-mentioned issues are highly related to the participation of lithium salts during the sintering process of NMC811 precursor. According to our obtained results, it is suggested that the structural ordering and relative electrochemical lithium storage performances of ternary Ni-rich cathode materials can be significantly improved through the manipulation of lithium salt reaction during post-annealing processes of their precursors. Herein, this proposal aims at regulating and controlling reactions of lithium salts during the synthesis of NMC811 material by using pre-heating processes of the precursor, followed by controllable fabrication of Li2YO3 (Y=Ti、Zr and Mn) shells. As a result, a high degree of structure ordering and low content of residual alkaline byproducts can be realized in layered NMC 811 material. Achievements of this proposal will reveal the working mechanism of Li2YO3 shell on manipulating lithium precursor reactions as well as the structure-function relationship between different Li2YO3 shells and enhanced electrochemical performances of NMC811 cathode material. It could also offer scientific evidences and rationalities for optimizing layered structures and electrochemical behaviors through artificial interfaces for ternary Ni-rich layered materials.