Ni-rich LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) is considered as a promising cathode material for high-capacity power batteries. Nevertheless, the rapid capacity fading during the charge/discharge process and inferior rate capability hinder their successful realization. Elemental doping plays a critical role in stabilizing the structure, inhibiting Li/Ni disorder, reducing polarization, improving electronic conductivity and enhancing Li-diffusion coefficient from the viewpoints of dopant radius, valence state and bonding energy. Herein, niobium (Nb), with optimal radius (0.64 Å), high valence state (Nb⁵⁺) and strong Nb-O bonding energy (753 kJ/mol), is introduced into NCM811 structure to improve the electrochemical performance and to evaluate this strategy. Then, X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy and electrochemical characterization are carried out to comprehensively evaluate the influence of Nb-doping on structure and electrochemical performance of NCM811 cathodes. Consequently, NCM811 cathode, with 1 at.% Nb, exhibited the highest capacity retention of 94.55% after 100 charge/discharge cycles (1 C) and rendered a superior charge storage capacity of 151.46 mAh/g at a high current rate of 5 C, demonstrating the effectiveness of the proposed strategy.

富镍LiNi _0.8 Co _0.1 Mn _0.1 O ₂（NCM811）被认为是用于大容量动力电池的有希望的正极材料。然而，在充电/放电过程中快速的容量衰减和较差的速率容量阻碍了它们的成功实现。从掺杂剂半径，价态和键能的观点来看，元素掺杂在稳定结构，抑制Li / Ni无序，降低极化，提高电子电导率和提高Li扩散系数方面起着关键作用。在此，铌（Nb）具有最佳半径（0.64Å），高价态（Nb ⁵⁺）和强Nb-O键能（753 kJ / mol）被引入NCM811结构以改善电化学性能并评估该策略。然后，进行了X射线衍射，透射电子显微镜，场发射扫描电子显微镜，能量色散光谱，X射线光电子光谱和电化学表征，以综合评估Nb掺杂对NCM811阴极结构和电化学性能的影响。因此，具有1 at。％Nb的NCM811阴极在100次充/放电循环（1 C）之后表现出94.55％的最高容量保持率，并在5 C的高电流速率下提供了151.46 mAh / g的优异电荷存储容量，证明了所提出策略的有效性。