Lithiation-assisted exfoliation and reduction of SnS2 to SnS decorated on lithium-integrated graphene for efficient energy storage
Lithiation-assisted exfoliation and reduction of SnS2 to SnS decorated on lithium-integrated graphene for efficient energy storage
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锂化辅助剥离和将 SnS2 还原为装饰在锂集成石墨烯上的 SnS，用于高效储能
DOI：
10.1039/c7nr06798d
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发表时间：
2017
期刊：
影响因子：
6.7
通讯作者：
Zhiwen Chen
中科院分区：
文献类型：
--
作者：
Bing Zhao;Fang Chen;Zhixuan Wang;Shoushuang Huang;Yong Jiang;Zhiwen Chen
硫化亚锡/石墨烯复合材料库仑效率低的主要原因是硫化锂返回率低和缺陷导致不可逆容量损失。本文以SnS_2、正丁基锂和氧化石墨烯为原料，采用一种新型的锂辅助剥离还原方法合成了SnS/石墨烯复合材料。实验结果表明，插入剂中的锂与氧化石墨烯上的含氧基团结合，有助于在焙烧过程中将六方SnS2还原为正交SnS，并同时占据石墨烯的边缘和缺陷位，从而减少了最初几个锂化过程中的额外锂离子消耗。微观结构表征表明，剥离的SnS纳米片的横向尺寸明显减小(50-100 nm)，均匀地装饰在锂集成石墨烯的表面。因此，所制备的SnS/石墨烯复合材料具有显著的SnS利用率，初始库仑效率为77.5%，这是目前文献中报道的最高值。此外，该复合电极表现出良好的可逆性(SnS+2Li++2E−↔Sn+Li2S)和100次循环后1016.4 mA h g−1的高可逆容量，表明它是一种重要的储能负极材料。
Low reversion of lithium sulfide and defects causing irreversible capacity loss are the primary causes of low Coulombic efficiency in tin sulfide/graphene-based composites. Herein, we synthesized a SnS/graphene composite via a novel lithiation-assisted exfoliation and reduction method using SnS2, n-butyllithium, and graphene oxide as raw materials. The experimental results reveal that lithium from the insertion agent combine with the oxygen-containing groups on graphene oxide; this can help in the reduction of hexagonal SnS2 to orthorhombic SnS during calcination and simultaneous pre-occupancy of the edge and defect sites of graphene; thus, additional lithium ion consumption during the initial several lithiation processes is diminished. Microstructural characterizations indicate that the exfoliated SnS nanosheets with a dramatically decreased lateral size (50–100 nm) are uniformly decorated on the surface of lithium-integrated graphene sheets. Consequently, the as-prepared SnS/graphene composite exhibits a significantly high SnS ultilization with a 77.5% initial Coulombic efficiency, which is the highest value reported in the current literature. Moreover, an excellent reversibility of conversion reaction (SnS + 2Li+ + 2e− ↔ Sn + Li2S) and a high reversible capacity of 1016.4 mA h g−1 after 100 cycles are expressed in this composite electrode, demonstrating its importance as an anode material for energy storage.