Zhu He, Tang Yu, Wiaderek Kamila M, Borkiewicz Olaf J, Ren Yang, Zhang Jian, Ren Jincan, Fan Longlong, Li Cheng Chao, Li Danfeng, Wang Xun-Li, Liu Qi
Department of Physics, City University of Hong Kong, Hong Kong 999077, P.R. China.
College of Physics and Materials Science, Tianjin Normal University, Tianjin 300387, P.R. China.
Nano Lett. 2021 Dec 8;21(23):9997-10005. doi: 10.1021/acs.nanolett.1c03613. Epub 2021 Nov 23.
The capacity degredation in layered Ni-rich LiNiCoMnO ( ≥ 0.8) cathode largely originated from drastic surface reactions and intergranular cracks in polycrystalline particles. Herein, we report a highly stable single-crystal LiNiCoMnO cathode material, which can deliver a high specific capacity (∼209 mAh g at 0.1 C, 2.8-4.3 V) and meanwhile display excellent cycling stability (>96% retention for 100 cycles and >93% for 200 cycles). By a combination of X-ray diffraction and pair distribution function analysis, an intermediate monoclinic distortion and irregular H3 stack are revealed in the single crystals upon charging-discharging processes. These structural changes might be driven by unique Li-intercalation kinetics in single crystals, which enables an additional strain buffer to reduce the cracks and thereby ensure the high cycling stability.
层状富镍LiNiCoMnO（≥0.8）正极的容量衰减主要源于多晶颗粒中剧烈的表面反应和晶间裂纹。在此，我们报道了一种高度稳定的单晶LiNiCoMnO正极材料，其在0.1 C、2.8 - 4.3 V下可提供高比容量（约209 mAh g），同时展现出优异的循环稳定性（100次循环保留率>96%，200次循环保留率>93%）。通过结合X射线衍射和对分布函数分析，发现在充放电过程中，单晶中存在中间单斜畸变和不规则的H3堆积。这些结构变化可能由单晶中独特的锂嵌入动力学驱动，这使得额外的应变缓冲能够减少裂纹，从而确保高循环稳定性。
