Zhao Tingting, Liu Pei, Tang Fuli, Xiao Minzhi, Song Liubin, Kuang Yinjie, Long Tianyuan, Xiao Zhongliang
College of Chemistry and Chemical Engineering, Changsha University of Science and Technology, Changsha 410114, Hunan, People's Republic of China.
Testing Technology Company of Changsha Research Institute of Mining and Metallurgy Co., LTD, Changsha 410114, Hunan, People's Republic of China.
Nanotechnology. 2023 Sep 22;34(49). doi: 10.1088/1361-6528/acf670.
LiNiCoMnO(NCM811) is one of the most promising cathode materials for high-energy lithium-ion batteries, but there are still problems such as rapid capacity decay during charge and discharge and poor cycle performance. Elemental doping can significantly improve the electrochemical performance of high nickel ternary cathode materials. In this work, Nb-doped NCM811 cathode material was successfully synthesized. The results show that Nbdoping helps to increase the interlayer spacing of the lithium layer, electron transport, and structural stability, thereby significantly improving the conductivity of Li. At a high voltage of 4.6 V, the initial discharge specific capacity of 1% Nb-doped NCM811 cathode material at 0.1 C is 222.3 mAh·g, and the capacity retention rate after 100 cycles at 1 C is 92.03%, which is far more than the capacity retention rate of NCM811 under the same conditions (74.30%). First-principles calculations prove that 1% Nb-doped NCM811 cathode material shows the highest electronic conductivity and Nbdoping will not change the lattice structure, demonstrating the effectiveness of the proposed strategy.
锂镍钴锰氧化物（NCM811）是高能锂离子电池最具潜力的正极材料之一，但仍存在充放电过程中容量快速衰减和循环性能差等问题。元素掺杂可显著改善高镍三元正极材料的电化学性能。在本工作中，成功合成了铌掺杂的NCM811正极材料。结果表明，铌掺杂有助于增加锂层的层间距、电子传输和结构稳定性，从而显著提高锂的电导率。在4.6 V的高电压下，1%铌掺杂的NCM811正极材料在0.1 C下的初始放电比容量为222.3 mAh·g，在1 C下100次循环后的容量保持率为92.03%，远高于相同条件下NCM811的容量保持率（74.30%）。第一性原理计算证明，1%铌掺杂的NCM811正极材料具有最高的电子电导率，且铌掺杂不会改变晶格结构，证明了所提策略的有效性。
