Wang Ying, Wu Shengxiang, Wang Chao, Wang Yijing, Han Xiaopeng
School of Chemistry & Materials Science, Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials, Jiangsu Normal University, Xuzhou, China.
Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of Chemistry, Nankai University, Tianjin, China.
Front Chem. 2019 Jan 10;6:654. doi: 10.3389/fchem.2018.00654. eCollection 2018.
Rational design of high performance anode material with outstanding rate capability and cycling stability is of great importance for lithium ion batteries (LIBs). Herein, a series of NiO/NiFeO hetero-structures with adjustable porosity, particle size, and shell/internal structure have been synthesized via a controllable annealing process. The optimized NiO/NiFeO (S-NFO) is hierarchical hollow nanocube that is composed of ~5 nm subunits and high porosity. When being applied as anode for LIBs, the S-NFO exhibits high rate capability and excellent cycle stability, which remains high capacity of 1,052 mAh g after 300 cycles at 5.0 A g and even 344 mAh g after 2,000 cycles at 20 A g. Such impressive electrochemical performance of S-NFO is mainly due to three reasons. One is high porosity of its hierarchical hollow shell, which not only promotes the penetration of electrolyte, but also accommodates the volume change during cycling. Another is the small particle size of its subunits, which can effectively shorten the electron/ion diffusion distance and provide more active sites for Li storage. Besides, the hetero-interfaces between NiO and NiFeO also contribute toitsfast charge transport.
设计具有出色倍率性能和循环稳定性的高性能阳极材料对锂离子电池（LIBs）至关重要。在此，通过可控退火工艺合成了一系列具有可调孔隙率、粒径和壳/内部结构的NiO/NiFeO异质结构。优化后的NiO/NiFeO（S-NFO）是由~5nm亚基组成且具有高孔隙率的分级空心纳米立方体。当用作LIBs的阳极时，S-NFO表现出高倍率性能和出色的循环稳定性，在5.0A g下循环300次后仍保持1052mAh g的高容量，在20A g下循环2000次后甚至达到344mAh g。S-NFO如此令人印象深刻的电化学性能主要归因于三个原因。一是其分级空心壳的高孔隙率，这不仅促进了电解质的渗透，还能适应循环过程中的体积变化。二是其亚基的小粒径，这可以有效缩短电子/离子扩散距离并为锂存储提供更多活性位点。此外，NiO和NiFeO之间的异质界面也有助于其快速电荷传输。
