不同管径多壁碳纳米管与硫含量对锂硫电池单质硫正极电化学性能的影响  

Preparation of multi-wall carbon nanotube/S composites as cathodes for lithium/sulfur batteries

作　　者：陈君政[1] 吴锋[1,2] 陈人杰[1,2] 李丽[1,2] 陈实[1,2] 

机构地区：[1]北京理工大学化工与环境学院环境科学工程北京市重点实验室,北京100081 [2]国家高技术绿色材料发展中心,北京100081

出　　处：《新型炭材料》2013年第6期428-434,共7页New Carbon Materials

基　　金：科技部国际合作项目(2010DFB63370);国家高技术研究发展计划(863计划;2011AA11A256);国家自然科学基金项目(21373028);北京市科技新星计划(2010B018)~~

摘　　要：采用分段加热法合成了不同管径、不同硫含量的单质硫一多壁碳纳米管（S-MWCNT）复合材料，利用电化学方法、SEM、TEM、比表面吸附等分析方法，筛选出以10～20mm直径的MWCNT为核，质量分数85％硫为壳的最优化条件下的复合材料。SEM测试显示单质硫均匀填充到MWCNT的中空管和层间的孔中形成了结构稳定的复合物。在最优化的条件下，复合材料首次放电比容量达1272．8mAh·g-2，活性物质利用率为76．0％，循环至第80周时放电容量还保持在720．1mAh·g-2，容量保持率高达64．4％。与未添加MWCNT的单质硫电极相比，硫复合电极活性物质的利用率和循环性能都得到了较大的改善。Multi-wall carbon nanotubes （MWCNTs） with different diameters were ball-milled with different amounts of elemental sulfur for 2 h under an argon atmosphere, and then heated at 155℃ for 24h followed by heating at 300℃ for 2h to prepare MWC- NT/S composites. The composites were characterized by N2 adsorption, scanning and transmission electron microscopy, and elec- trochemical tests. It was found that the composite showing the best performance was the one in which the MWCNT diameter was in the range 10-20nm and the sulfur content was 85 mass%. SEM confirms that the composite has a MWCNT-core and sulfur-shell structure. Sulfur not only covered the surface of the MWCNTs, but also filled the voids between the tubes. For the optimized com- posite the initial discharge capacity is 1272.8mAh.g-l-sulfur and the capacity remaining after 80 cycles is 720.1 mAh.g-l-sulfur. Its active material utilization and capacity retention rates are 76.0 and 64.4%, respectively. The active material utilization and cycling performance of the composite are greatly improved compared with a sulfur electrode without the MWCNTs, owing to a high electri- cal conductivity of the MWCNTs and the stable structure of the composite.

关 键 词：不同管径 多壁碳纳米管 锂硫电池 单质硫正极 

分 类 号：TM912.9[电气工程—电力电子与电力传动]