SnS2- Compared to SnO2-Stabilized S/C Composites toward High-Performance Lithium Sulfur Batteries

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• 作者：Xiaona Li ; Yue Lu ; Zhiguo Hou ; Wanqun Zhang ; Yongchun Zhu ; Yitai Qian ; Jianwen Liang ; Yitai Qian
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：August 3, 2016
• 年：2016
• 卷：8
• 期：30
• 页码：19550-19557
• 全文大小：574K
• 年卷期：0
• ISSN：1944-8252

文摘

The common sulfur/carbon (S/C) composite cathodes in lithium sulfur batteries suffer gradual capacity fading over long-term cycling incurred by the poor physical confinement of sulfur in a nonpolar carbon host. In this work, these issues are significantly relieved by introducing polar SnO₂ or SnS₂ species into the S/C composite. SnO₂- or SnS₂-stabilized sulfur in porous carbon composites (SnO₂/S/C and SnS₂/S/C) have been obtained through a baked-in-salt or sealed-in-vessel approach at 245 °C, starting from metallic tin (mp 231.89 °C), excess sulfur, and porous carbon. Both of the in situ-formed SnO₂ and SnS₂ in the two composites could ensure chemical interaction with lithium polysulfide (LiPS) intermediates proven by theoretical calculation. Compared to SnO₂/S/C, the SnS₂/S/C sample affords a more appropriate binding effect and shows lower charge transfer resistance, which is important for the efficient redox reaction of the adsorbed LiPS intermediates during cycling. When used as cathodes for Li–S batteries, the SnS₂/S/C composite with sulfur loading of 78 wt % exhibits superior electrochemical performance. It delivers reversible capacities of 780 mAh g^–1 after 300 cycles at 0.5 C. When further coupled with a Ge/C anode, the full cell also shows good cycling stability and efficiency.