High nickel content LiNi_xCo_yMn_1–x–yO₂ (NCM) cathode materials have been attracting increasing attention owing to their significant advantages, but in practical application, because of their poor storage performance their production and transportation cost a lot. The gap between polycrystalline particles can very easily become the site where impurities are first generated; thus, whether the single crystal structure will affect the storage properties of high nickel content NCM materials is worth studying. In this work, we take two typical high nickel content ternary materials, LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) and LiNi_0.6Co_0.2Mn_0.2O₂ (NCM622), as samples to study the differences in properties of single-crystal and polycrystalline materials after storage. Through comparative research, under the same storage conditions, the single-crystal structure materials have significantly less impurities formed on the surface, the structural stability of materials is obviously better, and they can also exhibit superior electrochemical performance after storage. Particularly for the NCM811 materials with a higher nickel amount, the specific capacity of polycrystalline NCM811 materials basically comes nearly to zero after storage, but the single-crystal structure NCM811 materials can still perform a relatively stable cycle with a certain capacity. It can be concluded from the work that for high nickel content NCM cathode materials, the single-crystal structure can greatly improve its storage performance.

中文翻译：

---

单晶相对于多晶LiNi _x Co _y Mn _{1– x – y} O ₂阴极材料在锂离子电池存储行为方面的优越性

高镍含量的LiNi _x Co _y Mn _{1– x – y} O ₂（NCM）正极材料由于其显着的优势而受到越来越多的关注，但是在实际应用中，由于其较差的存储性能，其生产和运输成本很高。多晶颗粒之间的缝隙很容易成为首先产生杂质的位置。因此，单晶结构是否会影响镍含量高的NCM材料的存储性能值得研究。在这项工作中，我们采用两种典型的高镍含量三元材料LiNi _0.8 Co _0.1 Mn _0.1 O ₂（NCM811）和LiNi _0.6 Co _0.2 Mn _0.2 O ₂（NCM622），作为研究储存后单晶和多晶材料性能差异的样本。通过比较研究，在相同的储存条件下，单晶结构材料表面形成的杂质明显减少，材料的结构稳定性明显更好，并且在储存后还表现出优异的电化学性能。特别是对于镍含量较高的NCM811材料，多晶NCM811材料的比容在存储后基本上接近于零，但单晶结构NCM811材料仍可以以一定容量执行相对稳定的循环。从这项工作可以得出结论，对于高镍含量的NCM阴极材料，