Ionic liquid treated carbon nanotube sponge as high areal capacity cathode for lithium sulfur batteries
Ionic liquid treated carbon nanotube sponge as high areal capacity cathode for lithium sulfur batteries
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DOI：
10.1007/s10800-018-1181-7
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发表时间：
2018-05-01
影响因子：
2.9
通讯作者：
Yu, Choongho
中科院分区：
文献类型：
--
作者：
Lin, Henry Taisun;Yang, Gang;Yu, Choongho
将离子液体（1-乙基-3-甲基咪唑四氟硼酸盐）处理的碳纳米管（CNT）海绵作为锂硫电池阴极的导电基质和多硫化物储库进行了测试。X射线光电子能谱的结果证实，这种处理掺杂的碳纳米管的表面上的氟和氧，和实验结果表明，这种处理有显着提高吸附的多硫化物的碳纳米管海绵。结果，该海绵阴极容纳8 mg cm（-2）的显著高的硫面积负载，在1.28mA cm（-2）的面积电流密度下在第100次循环时显示出7.1mAh cm（-2）的高面积容量，每个循环的平均容量衰减为0.048%。使用密度泛函理论计算Li 2S 6在F/O掺杂的碳结构上的吸附能，证实掺杂使得多硫化物吸附特别稳定，这是由于氟。本研究提供了一种有用的方法，同时引入氟和氧的碳，以显着提高多硫化物的吸附在碳阴极，从而获得高的面积放电容量，这是更重要的比放电容量的实际电池运行。[图形]。
Ionic liquid (1-ethyl-3-methylimidazolium tetrafluoroborate) treated carbon nanotube (CNT) sponges were tested as a conductive matrix and polysulfide reservoir for the cathode of lithium-sulfur batteries. X-ray photoelectron spectroscopy results confirmed that this treatment doped fluorine and oxygen on the surface of the CNT, and experimental results showed that this treatment had significantly improved adsorption of polysulfides in the CNT sponge. As a result, this sponge cathode accommodated a remarkably high sulfur areal loading of 8 mg cm(-2), showing a high areal capacity of 7.1 mAh cm(-2) at the 100th cycle at an areal current density of 1.28 mA cm(-2) with an average capacity fading of 0.048% per cycle. The adsorbing energy of Li2S6 on the F/O-doped carbon structure was calculated using the density functional theory, confirming that the doping made the polysulfide adsorption stable particularly due to fluorine. This study provides a useful approach of simultaneously introducing both fluorine and oxygen to carbon in order to significantly improve the polysulfide adsorption on the carbon cathode and thereby obtain high areal discharge capacity, which is much more important than specific discharge capacity for actual battery operation.[GRAPHICS].