Nanowire-templated formation of SnO2/carbon nanotubes with enhanced lithium storage properties.
Nanowire-templated formation of SnO2/carbon nanotubes with enhanced lithium storage properties.
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DOI：
10.1039/c6nr01272h
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发表时间：
2016-04
期刊：
影响因子：
6.7
通讯作者：
Xiaosi Zhou;Le Yu;X. Lou
中科院分区：
文献类型：
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作者：
Xiaosi Zhou;Le Yu;X. Lou
在这项工作中，我们设计和合成SnO 2纳米管包裹的多孔碳层通过多步方法。单晶MnO（x）纳米线被用作模板。通过简单的水热法在MnO（x）纳米线上生长SnO 2，得到MnO（x）/SnO 2核壳纳米电缆，并在其表面包覆一层聚多巴胺。聚多巴胺碳化并选择性去除MnO（x）纳米线后，得到碳包覆的SnO 2纳米管。这种结构结合了几个优点。首先，管状结构的内部空的空间可以适当地缓冲在锂插入-拔出过程期间的巨大体积变化，导致改善的循环性能。其次，纳米尺寸的SnO 2亚单元和多孔碳涂层不仅缩短了锂离子扩散的距离，而且还为快速Li（+）穿过界面提供了大的电极-电解质接触面积，从而能够提高倍率性能。第三，柔性碳涂层紧密地覆盖在SnO 2纳米晶体上，这可以促进电子输运并且还显著地减轻粉碎。结果表明，所合成的SnO 2/C-NT纳米复合材料在200次循环后表现出596 mA h g（-1）的高可逆容量和优异的倍率性能。
In this work, we have designed and synthesized SnO2 nanotubes wrapped by a porous carbon layer via a multistep method. Single-crystalline MnO(x) nanowires are employed as the template. SnO2 is grown on MnO(x) nanowires by a simple hydrothermal method to generate MnO(x)/SnO2 core-shell nanocables, followed by further coating with a layer of polydopamine. After carbonization of polydopamine and selective removal of MnO(x) nanowires, carbon coated SnO2 nanotubes are obtained. This structure combines several advantages. First, the internal empty space of the tubular structure can buffer the huge volume variation during lithium insertion-extraction processes properly, leading to improved cycling performance. Second, the nanosized SnO2 subunits and porous carbon coating not only shorten the distance for lithium ion diffusion but also offer large electrode-electrolyte contact area for fast Li(+) crossing the interface, thus enabling improved rate capability. Third, the flexible carbon coating is closely covered onto the SnO2 nanocrystals, which could facilitate the electronic transport and also significantly mitigate the pulverization. As a result, the as-synthesized SnO2/C-NT nanocomposites exhibit a high reversible capacity of 596 mA h g(-1) after 200 cycles, as well as an outstanding rate capability.