Quantitatively regulating defects of 2D tungsten selenide to enhance catalytic ability for polysulfide conversion in a lithium sulfur battery
Quantitatively regulating defects of 2D tungsten selenide to enhance catalytic ability for polysulfide conversion in a lithium sulfur battery
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DOI：
10.1016/j.ensm.2021.11.024
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发表时间：
2022-01-22
影响因子：
20.4
通讯作者：
Gao, Xue-Ping
中科院分区：
文献类型：
--
作者：
Li, Hao-Jie;Xi, Kai;Gao, Xue-Ping
在二维材料中引入缺陷可以增加配位不饱和位点，这些位点通常也是催化活性位点。缺陷水平如何影响催化性能以及如何利用缺陷来优化二维材料？在这项工作中，阴离子 Se 空位和边缘位错在 2D WSe2 中受到调节，作为硫阴极过渡金属二硫属化物主体材料的模型。定量研究了具有不同 W/Se 比的有缺陷的二维 WSe2，以研究缺陷对增强锂硫（Li-S）电池阴极过程的影响。 WSe1.51具有中等程度的缺陷，在吸附多硫化物、催化多硫化物转化和促进液固转化方面表现出最佳性能，所有这些都是锂硫电池的关键步骤。相应的硫正极具有11.3 mAh cm(-2)的高初始面积容量和优异的循环稳定性，在1C倍率下1000次循环期间衰减率为0.025%。即使在软包电池中，仍然具有出色的循环性能和灵活性。结果表明，通过控制缺陷水平来增强二维过渡金属二硫属化物的催化能力，从而实现长循环、高能量的Li-S可充电电池是可行的。
Introducing defects into 2D materials can increase the coordinatively unsaturated sites that are usually also catalytically active sites. How does the level of defects influence catalytic performance and how to take advantage of defects to optimize the 2D materials? In this work, anionic Se vacancies and edge dislocations are regulated in 2D WSe2 as a model of transition metal dichalcogenide host material for the sulfur cathode. The defective 2D WSe2 with different W/Se ratios are quantitatively investigated the influence of the defects on enhancing the cathodic process in lithium sulfur (Li-S) batteries. With a moderate level of defects, WSe1.51 shows the optimal performance for adsorbing polysulfides, catalysing polysulfides conversion, and promoting liquid-solid transformation, all of which are crucial steps for Li-S battery. The corresponding sulfur cathode delivers a high initial areal capacity of 11.3 mAh cm(-2), and excellent cycle stability with a decay rate of 0.025% during 1000 cycles at 1C rate. Even in a pouch cell, the excellent cyclability and flexibility are still available. The results show the feasibility of enhancing the catalytic ability of 2D transition metal dichalcogenide by controlling the level of defects by which a long-cycle and high-energy Li-S rechargeable battery can be achieved.