LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cathode material is widely used due to its high capacity and low cost but it shows poor cycle stability. It is well established that B³⁺ plays an active role in the charge–discharge cycle of high-Ni ternary cathodes. However, the role of B³⁺ in the cathode structure is rarely discussed. In this work, a simple and efficient solid-state method was used to prepare B-doped NCM811 samples. The results indicate that after 100 cycles at 1C, B-NCM811 exhibited excellent cycling stability with cycle retention rates of 90.7% and 81.3% over 2.7–4.3 V and 2.7–4.5 V, respectively. CV and EIS results indicate that B-doping effectively reduced charge transfer impedance and polarization, which was confirmed by DOS calculation results. Combined with DFT calculations, it was found that B³⁺ in the transition metal (TM) gap tends to bond with oxygen to form BO₄ tetrahedra, and strong B–O bonds can improve structural stability. Moreover, B-doping increased the length of the Li–O bond, reducing the Li⁺ migration barrier. This study demonstrates that B-doping effectively enhances the structural stability of Ni-rich layered cathodes.

中文翻译：

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固相法制备的B掺杂LiNi0.8Co0.1Mn0.1O2阴极的增强循环性能


LiNi_0.8Co_0.1Mn_0.1O₂ （NCM811） 正极材料因其高容量和低成本而被广泛使用，但它表现出较差的循环稳定性。众所周知，B³⁺ 在高 Ni 三元阴极的充放电循环中起着积极作用。然而，B³⁺ 在阴极结构中的作用很少被讨论。在这项工作中，采用一种简单高效的固态方法制备了 B 掺杂的 NCM811 样品。结果表明，在 1C 下循环 100 次后，B-NCM811 表现出优异的循环稳定性，在 2.7-4.3 V 和 2.7-4.5 V 上的循环保持率分别为 90.7% 和 81.3%。CV 和 EIS 结果表明，B 掺杂有效地降低了电荷转移阻抗和极化，DOS 计算结果证实了这一点。结合 DFT 计算，发现过渡金属 （TM） 间隙中的 B³⁺ 倾向于与氧键合形成 BO₄ 四面体，而强 B-O 键可以提高结构稳定性。此外，B 掺杂增加了 Li-O 键的长度，降低了 Li⁺ 迁移势垒。本研究表明，B 掺杂有效增强了富镍层状阴极的结构稳定性。