Hierarchical Porous LiNi1/3Co1/3Mn1/3O2 Nano-/Micro Spherical Cathode Material: Minimized Cation Mixing and Improved Li(+) Mobility for Enhanced Electrochemical Performance.
Hierarchical Porous LiNi1/3Co1/3Mn1/3O2 Nano-/Micro Spherical Cathode Material: Minimized Cation Mixing and Improved Li(+) Mobility for Enhanced Electrochemical Performance.
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DOI：
10.1038/srep25771
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发表时间：
2016-05-17
影响因子：
4.6
通讯作者：
Shen Z
中科院分区：
文献类型：
--
作者：
Chen Z;Wang J;Chao D;Baikie T;Bai L;Chen S;Zhao Y;Sum TC;Lin J;Shen Z
LiNi 1/3Co 1/3 Mn 1/3 O2（NCM）被认为是锂离子电池（LIB）最有前途的正极材料之一，但由于Li+/Ni 2+阳离子混合抑制了Li+的迁移率，导致其倍率性能和循环稳定性较差。本研究以蓬松的MnO 2为模板剂，采用两步法制备了分级多孔纳米/微球NCM（PNM-NCM）。具体而言，PNM-NCM微球在0.1C下实现了207.7 mAh g-1的高可逆比容量，具有优异的倍率性能（1C和2C下分别为163.6和148.9 mAh g-1），并且在50次循环后可逆容量保持率可以良好地保持高达90.3%。这种优异的电化学性能归因于独特的分级多孔纳米/微球结构，其可以增加与电解质的接触面积，缩短Li+扩散路径，从而提高Li+迁移率。此外，如XRD Rietveld精修分析所揭示的，可忽略的阳离子混合（1.9%）和具有良好形成的层状结构的高结晶度也有助于增强的C速率性能和循环稳定性。在我们的研究的基础上，可以建立一个有效的策略来揭示这些材料的结构/化学与其性能之间的基本关系。
Although being considered as one of the most promising cathode materials for Lithium-ion batteries (LIBs), LiNi1/3Co1/3Mn1/3O2 (NCM) is currently limited by its poor rate performance and cycle stability resulting from the thermodynamically favorable Li+/Ni2+ cation mixing which depresses the Li+ mobility. In this study, we developed a two-step method using fluffy MnO2 as template to prepare hierarchical porous nano-/microsphere NCM (PNM-NCM). Specifically, PNM-NCM microspheres achieves a high reversible specific capacity of 207.7 mAh g−1 at 0.1 C with excellent rate capability (163.6 and 148.9 mAh g−1 at 1 C and 2 C), and the reversible capacity retention can be well-maintained as high as 90.3% after 50 cycles. This excellent electrochemical performance is attributed to unique hierarchical porous nano-/microsphere structure which can increase the contact area with electrolyte, shorten Li+ diffusion path and thus improve the Li+ mobility. Moreover, as revealed by XRD Rietveld refinement analysis, a negligible cation mixing (1.9%) and high crystallinity with a well-formed layered structure also contribute to the enhanced C-rates performance and cycle stability. On the basis of our study, an effective strategy can be established to reveal the fundamental relationship between the structure/chemistry of these materials and their properties.