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ZIF-7@carbon composites as multifunctional interlayer for rapid and durable Li-S performance
Journal of Energy Chemistry ( IF 13.1 ) Pub Date : 2020-09-19 , DOI: 10.1016/j.jechem.2020.09.019
Xingbo Wang , Yan Zhao , Feichao Wu , Shuming Liu , Zisheng Zhang , Zhaoyang Tan , Xiaohang Du , Jingde Li

The notorious “shuttle effect” of polysulfide during charge–discharge process induces grievous capacity fading, while the sluggish polysulfide conversion kinetics significantly hinders the development of practically viable lithium-sulfur (Li-S) batteries. In this study, a novel ZIF-7@carbon composite with ZIF-7 sheets vertically rooted on carbon cloth was developed as multifunctional interlayer to address these issues. The composite shows directional layered structure with outstanding compactness, and thus can provide massive active sites for accelerated redox reactions. The pore channels are perpendicular to the square surface, resulting in extremely high utilization of one-dimensional channels. Therefore, this structure can not only maintain the structural stability during the charge–discharge process by providing enough space for volume expansion, but also contribute to efficient exposure and utilization of active sites for the physical/chemical adsorption and catalytic conversion of polysulfide. As a result, Li-S batteries with the as-developed interlayer deliver a considerable areal capacity of 4.75 mAh cm−2 at an elevated sulfur loading of 5.5 mg cm−2, and an impressive cyclability with an extremely low capacity-fading rate of merely 0.04% per cycle over 500 cycles at 1 C.



中文翻译:

ZIF-7 @碳复合材料作为多功能夹层,可实现快速耐用的Li-S性能

多硫化物在充放电过程中臭名昭著的“穿梭效应”引起严重的容量衰减,而低聚多硫化物转化动力学则显着阻碍了切实可行的锂硫(Li-S)电池的发展。在这项研究中,开发了一种新型的ZIF-7 @碳复合材料,其中ZIF-7片垂直植根于碳布上,作为多功能中间层来解决这些问题。该复合材料显示出定向层状结构,具有出色的致密性,因此可以为加速氧化还原反应提供大量的活性位点。孔道垂直于正方形表面,导致一维通道的利用率极高。因此,这种结构不仅可以通过提供足够的体积扩展空间来维持充放电过程中的结构稳定性,而且还有助于有效暴露和利用活性位点进行多硫化物的物理/化学吸附和催化转化。结果,具有已开发的中间层的Li-S电池可提供4.75 mAh cm的相当大的面积容量-2在5.5毫克cm的升高硫负载-2,和令人印象深刻的可循环性以每循环只是0.04%以上500次循环以1C的极低容量衰落速率

更新日期:2020-09-19
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