A three dimensional sulfur/reduced graphene oxide with embedded carbon nanotubes composite as a binder-free, free-standing cathode for lithium–sulfur batteries
A three dimensional sulfur/reduced graphene oxide with embedded carbon nanotubes composite as a binder-free, free-standing cathode for lithium–sulfur batteries
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DOI：
10.1039/c7ra07418b
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发表时间：
2017-09
期刊：
影响因子：
3.9
通讯作者：
Ying Kongqing;R. Tian;Zhou Jie;Hua Li;R. Dugnani;Y. Lu;H. Duan;Yiping Guo;Hezhou Liu
中科院分区：
文献类型：
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作者：
Ying Kongqing;R. Tian;Zhou Jie;Hua Li;R. Dugnani;Y. Lu;H. Duan;Yiping Guo;Hezhou Liu
无粘结剂和自支撑电极被认为是锂硫电池中有吸引力和有前途的结构。在这项工作中，我们描述了如何独立的硫/还原氧化石墨烯嵌入碳纳米管电极已通过一种新的，简便和环保的方法，利用极性和非极性材料的溶解度差异的优势合成。首先，通过强烈的超声处理将非极性元素硫溶解在弱极性溶剂（乙醇）中。在随后的重极性溶剂（去离子水）逐滴过程中，纳米尺寸的硫颗粒从乙醇中沉淀并沉积在分散的碳纳米管和氧化石墨烯上。值得注意的是，由于抗坏血酸在75 °C下用作氧化石墨烯的还原剂，因此该过程不会产生有毒副产物。此外，具有嵌入的碳纳米管的“按设计”硫/还原氧化石墨烯氧化石墨烯显示出独特的结构，其中硫和碳纳米管都嵌入在还原氧化石墨烯的基面中。发现所制造的电极表现出优异的倍率性能和循环性能，在第三次循环中观察到的最大容量为1025 mA h g-1，并且在100次循环后稳定的容量为704 mA h g-1。
Binder-free and free-standing electrodes have been regarded as an attractive and promising structure in lithium–sulfur batteries. In this work we describe how a free-standing sulfur/reduced graphene oxide with embedded carbon nanotubes electrode has been synthesized by a novel, facile and eco-friendly method taking advantage of the solubility difference of polar and nonpolar materials. First, the nonpolar elemental sulfur is dissolved in a weak polar solvent (ethanol) by intensive ultrasonication. During a subsequent heavy polar solvent (deionized water) drop-wise procedure, nano-sized sulfur particles are precipitated from the ethanol and deposited on the dispersed carbon nanotubes and graphene oxide. Noticeably, since ascorbic acid is taken as the reducing agent for graphene oxide at 75 °C, the process produces no toxic byproducts. Besides, the ‘as-designed’ sulfur/reduced graphene oxide with embedded carbon nanotubes graphene oxide displays a unique structure with both the sulfur and carbon nanotubes embedded in the basal plane of reduced graphene oxide. The manufactured electrode is found to exhibit excellent rate capability and cyclability, with the maximum capacity of 1025 mA h g−1 observed in the third cycle and a stable capacity of 704 mA h g−1 after 100 cycles.