Abstract In this study, we have demonstrated that boron doping of Ni-rich Li[NixCoyAl1−x−y]O2 dramatically alters the microstructure of the material. Li[Ni0.885Co0.1Al0.015]O2 is composed of large equiaxed primary particles, whereas a boron-doped Li[Ni0.878Co0.097Al0.015B0.01]O2 cathode consists of elongated particles that are highly oriented to produce a strong, crystallographic texture. Boron reduces the surface energy of the (0 0 3) planes, resulting in a preferential growth mode that maximizes the (0 0 3) facet. This microstructure modification greatly improves the cycling stability; the Li[Ni0.878Co0.097Al0.015B0.01]O2 cathode maintains a remarkable 83% of the initial capacity after 1000 cycles even when it is cycled at 100% depth of discharge. By contrast, the Li[Ni0.885Co0.1Al0.015]O2 cathode retains only 49% of its initial capacity. The superior cycling stability clearly indicates the importance of the particle microstructure (i.e., particle size, particle shape, and crystallographic orientation) in mitigating the abrupt internal strain caused by phase transitions in the deeply charged state, which occurs in all Ni-rich layered cathodes. Microstructure engineering by surface energy modification, when combined with protective coatings and composition modification, may provide a long-sought method of harnessing the high capacity of Ni-rich layered cathodes without sacrificing the cycling stability.

中文翻译：

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用于高能锂离子电池的高度稳定的富镍 NCA 正极

摘要 在这项研究中，我们证明了富镍 Li[NixCoyAl1-x-y]O2 的硼掺杂显着改变了材料的微观结构。Li[Ni0.885Co0.1Al0.015]O2 由大的等轴初级粒子组成，而掺硼 Li[Ni0.878Co0.097Al0.015B0.01]O2 阴极由细长的粒子组成，这些粒子高度取向以产生强, 晶体结构。硼降低了 (0 0 3) 平面的表面能，从而形成了使 (0 0 3) 面最大化的优先生长模式。这种微结构改性大大提高了循环稳定性；Li[Ni0.878Co0.097Al0.015B0.01]O2 正极在 1000 次循环后仍保持显着的 83% 的初始容量，即使在 100% 放电深度下循环也是如此。相比之下，Li[Ni0.885Co0.1Al0.015]O2 正极仅保留了其初始容量的 49%。优异的循环稳定性清楚地表明粒子微观结构（即粒子大小、粒子形状和晶体取向）在减轻深度充电状态下相变引起的突然内部应变方面的重要性，这种应变发生在所有富镍层状正极中. 通过表面能改性的微结构工程，当与保护涂层和成分改性相结合时，可以提供一种长期寻求的方法，在不牺牲循环稳定性的情况下利用富镍层状正极的高容量。这发生在所有富镍层状阴极中。通过表面能改性的微结构工程，当与保护涂层和成分改性相结合时，可以提供一种长期寻求的方法，在不牺牲循环稳定性的情况下利用富镍层状正极的高容量。这发生在所有富镍层状阴极中。通过表面能改性的微结构工程，当与保护涂层和成分改性相结合时，可以提供一种长期寻求的方法，在不牺牲循环稳定性的情况下利用富镍层状正极的高容量。