Synthesis of Surface-Functionalized WS2 Nanosheets and Performance as Li-Ion Battery Anodes
Synthesis of Surface-Functionalized WS2 Nanosheets and Performance as Li-Ion Battery Anodes
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DOI：
10.1021/jz300480w
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发表时间：
2012-06-07
影响因子：
5.7
通讯作者：
Singh, G.
中科院分区：
文献类型：
--
作者：
Bhandavat, R.;David, L.;Singh, G.
将块体二硫化钨(WS2)分离成几层二维(2D)晶体是很有意义的，因为它们对于某些化学过程具有较高的比表面积，并且具有与尺寸相关的光学和电学特性。在这里，我们演示了一个过程，涉及到通过使用2 mg/mL的强酸处理(氯磺酸)物理分离弱结合的WS2层，然后在去离子(DI)水中淬火。经超强酸处理的WS2的X射线光电子能谱表明，W-O型键的形成意味着钨的氧化和硫相的还原。热重分析表明WS2表面发生了三相失重，表明WS2表面发生了酸性官能化。我们还研究了酸处理的WS2负极在锂半电池配置下的电化学行为，表现出三步充放电行为，具有转化反应的特征。50次循环后的电化学容量为118mAh/g。
Separation of bulk tungsten disulfide (or WS2) into few-layer two-dimensional (2-D) crystals is of interest because of their high surface area for certain chemical processes and size-dependent optical and electronic characteristics. Herein, we demonstrate a process that involves the physical separation of weakly bonded WS2 layers by use of a strong acid treatment (chlorosulfonic acid) at 2 mg/mL, followed by quenching in deionized (DI) water. X-ray photoelectron spectroscopy of the superacid-treated WS2 suggests the formation of W-O type bonds, signifying oxidation of tungsten and reduction of the sulfur phase. Thermogravimetric analysis showed a three-phase weight-loss pattern, suggesting acid functionalization of WS2 surfaces. We also studied the electrochemical behavior of an acid-treated WS2 anode in a lithium half-cell configuration that showed a three-step charge discharge behavior, characteristic of a conversion reaction. The electrochemical capacity was 118 mAh/g after 50 cycles.