Nitrogen- Doped Mesoporous Carbon Promoted Chemical Adsorption of Sulfur and Fabrication of High- Areal- Capacity Sulfur Cathode with Exceptional Cycling Stability for Lithium- Sulfur Batteries
Nitrogen- Doped Mesoporous Carbon Promoted Chemical Adsorption of Sulfur and Fabrication of High- Areal- Capacity Sulfur Cathode with Exceptional Cycling Stability for Lithium- Sulfur Batteries
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DOI：
10.1002/adfm.201302631
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发表时间：
2014-03-01
影响因子：
19
通讯作者：
Wang, Donghai
中科院分区：
文献类型：
--
作者：
Song, Jiangxuan;Xu, Terrence;Wang, Donghai
碳基作为硫磺正极的重要组成部分，对锂硫(Li-S)电池的电化学性能起着至关重要的作用。本文报道了一种新型锂-S电池正极材料--介孔掺氮碳硫纳米复合材料。X射线吸收近边结构谱证实，氮掺杂能有效地促进碳表面硫原子与氧官能团之间的化学吸附，密度泛函理论计算进一步揭示了氮的作用机理。基于多孔结构和氮掺杂的优点，MPNC-硫正极在0.7mAhcm(-2)的大电流密度下表现出优异的循环稳定性(100次循环保持率为95%)，高硫负载量(4.2mgS cm-2)和高硫含量(70wt%)。这种新型正极材料具有较高的比容量(约3.3mAhcm(-2))，这对锂S电池的实际应用具有重要意义。相信氮掺杂促进化学吸附的重要作用可以推广到其他高性能的锂S电池碳硫复合正极的开发中。
As one important component of sulfur cathodes, the carbon host plays a key role in the electrochemical performance of lithium-sulfur (Li-S) batteries. In this paper, a mesoporous nitrogen-doped carbon (MPNC)-sulfur nanocomposite is reported as a novel cathode for advanced Li-S batteries. The nitrogen doping in the MPNC material can effectively promote chemical adsorption between sulfur atoms and oxygen functional groups on the carbon, as verified by X-ray absorption near edge structure spectroscopy, and the mechanism by which nitrogen enables the behavior is further revealed by density functional theory calculations. Based on the advantages of the porous structure and nitrogen doping, the MPNC-sulfur cathodes show excellent cycling stability (95% retention within 100 cycles) at a high current density of 0.7 mAh cm(-2) with a high sulfur loading (4.2 mg S cm(-2)) and a sulfur content (70 wt%). A high areal capacity (approximate to 3.3 mAh cm(-2)) is demonstrated by using the novel cathode, which is crucial for the practical application of Li-S batteries. It is believed that the important role of nitrogen doping promoted chemical adsorption can be extended for development of other high performance carbon-sulfur composite cathodes for Li-S batteries.