Sun Ruimin, Liu Sijie, Wei Qiulong, Sheng Jinzhi, Zhu Shaohua, An Qinyou, Mai Liqiang
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Hubei, Wuhan, 430070, P. R. China.
Department of Chemistry, University of California, Berkeley, CA, 94720, USA.
Small. 2017 Oct;13(39). doi: 10.1002/smll.201701744. Epub 2017 Aug 21.
It is of great importance to exploit electrode materials for sodium-ion batteries (SIBs) with low cost, long life, and high-rate capability. However, achieving quick charge and high power density is still a major challenge for most SIBs electrodes because of the sluggish sodiation kinetics. Herein, uniform and mesoporous NiS nanospheres are synthesized via a facile one-step polyvinylpyrrolidone assisted method. By controlling the voltage window, the mesoporous NiS nanospheres present excellent electrochemical performance in SIBs. It delivers a high reversible specific capacity of 692 mA h g . The NiS anode also exhibits excellent high-rate capability (253 mA h g at 5 A g ) and long-term cycling performance (319 mA h g capacity remained even after 1000 cycles at 0.5 A g ). A dominant pseudocapacitance contribution is identified and verified by kinetics analysis. In addition, the amorphization and conversion reactions during the electrochemical process of the mesoporous NiS nanospheres is also investigated by in situ X-ray diffraction. The impressive electrochemical performance reveals that the NiS offers great potential toward the development of next generation large scale energy storage.
开发具有低成本、长寿命和高倍率性能的钠离子电池（SIBs）电极材料具有至关重要的意义。然而，由于缓慢的钠化动力学，实现快速充电和高功率密度仍然是大多数SIBs电极面临的主要挑战。在此，通过一种简便的一步聚乙烯吡咯烷酮辅助方法合成了均匀的介孔NiS纳米球。通过控制电压窗口，介孔NiS纳米球在SIBs中表现出优异的电化学性能。它具有692 mA h g的高可逆比容量。NiS负极还表现出优异的高倍率性能（在5 A g下为253 mA h g）和长期循环性能（在0.5 A g下循环1000次后仍保持319 mA h g的容量）。通过动力学分析确定并验证了主要的赝电容贡献。此外，还通过原位X射线衍射研究了介孔NiS纳米球在电化学过程中的非晶化和转化反应。令人印象深刻的电化学性能表明，NiS在下一代大规模储能的发展中具有巨大潜力。
