Aligned carbon nanotube/sulfur composite cathodes with high sulfur content for lithium-sulfur batteries
Aligned carbon nanotube/sulfur composite cathodes with high sulfur content for lithium-sulfur batteries
复制标题
用于锂硫电池的高硫含量的定向碳纳米管/硫复合正极
DOI：
10.1016/j.nanoen.2013.12.013
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发表时间：
2014-03-01
期刊：
影响因子：
17.6
通讯作者：
Wei, Fei
中科院分区：
文献类型：
--
作者：
Cheng, Xin-Bing;Huang, Jia-Qi;Wei, Fei
使用导电碳支架是获得用于锂硫电池的先进复合阴极的高效且有效的方法。然而，通常小于70wt%的负载量导致有限的能量密度，并且涉及高温和精细工艺的典型制造路线也限制了硫阴极的可制造性，这两者都阻碍了锂-硫电池的实际应用。本文采用可扩展的室温一步法制备碳纳米管（CNT）/硫复合阴极，其中排列的CNT充当互连的导电支架以容纳硫。当硫的负载量从50增加到90重量%时，CNT/硫的振实密度从0.4增加到1.98 g cm（-3），以及整个电极的质量/面积/体积容量（CNT/硫复合物和粘合剂）从500.3mAh g（-1）/0.298mAh cm（-2）/200.1mAh cm（-3）提高到563.7mAh g（-1）/0.893mAh cm（-2）/1116.0mAh cm（-3），分别复合阴极中硫含量的增加使得锂硫电池的能量密度显著增加。超高的硫负载量归因于排列的CNT支架的开放、有序、直孔结构，用于均匀分布细硫颗粒。稳健的sp2碳框架充当电子转移的快速途径，并且单个CNT在小束中的大纵横比、良好排列、有序堆积提供了低的导电逾渗阈值。因此，具有高负载含量的硫被有效地用于具有大大改善的能量密度的锂-硫电池。(C)2013爱思唯尔有限公司版权所有。
The use of conductive carbon scaffolds is efficient and effective to obtain advanced composite cathodes for lithium-sulfur batteries. However, the loading amount of mostly less than 70 wt% induces a limited energy density and the typical fabrication route involving high-temperature and elaborate process also limits the manufacturability of sulfur cathode, both of which hinder the practical application of lithium-sulfur batteries. Herein, a scalable, room-temperature, and one-step method is employed for carbon nanotube (CNT)/sulfur composite cathode, in which aligned CNTs served as interconnected conductive scaffolds to accommodate sulfur. When the loading amount of sulfur increased from 50 to 90 wt%, the tap density of CNT/sulfur increased from 0.4 to 1.98 g cm(-3), and the mass/areal/volumetric capacities of the whole electrodes (CNT/sulfur composites and binders) was improved from 500.3 mAh g(-1)/0.298 mAh cm(-2)/200.1 mAh cm(-3) to 563.7 mAh g(-1)/0.893 mAh cm(-2)/1116.0 mAh cm(-3), respectively. The rise of sulfur content in the composite cathode renders a dramatic increase of the energy density of lithium-sulfur cells. The ultra-high loading amount of sulfur is attributed to the open, ordered, straight pore structure of aligned CNT scaffolds for the uniform distribution of fine sulfur particles. The robust sp2 carbon frameworks served as rapid pathways for electron transfer, and the large aspect ratio, good alignment, ordered packing of individual CNT in small bundles offer a low conductive percolation threshold. Consequently, the sulfur with a high loading content was efficiently utilized for a lithium-sulfur cell with a much improved energy density. (C) 2013 Elsevier Ltd. All rights reserved.