论文标题
锂硫电池对WS2和WSE2的锚定行为的第一原则调查
First-Principles Investigation of Anchoring Behavior of WS2 and WSe2 for Lithium-Sulfur Batteries
论文作者
论文摘要
锂硫（LI-S）电池的商业实现由于锂多硫化物（LIPS）溶解到电解液中而迅速褪色，因此被阻塞。为了提高LI-S电池的效率和性能，据报道，过渡金属二分法源是有前途的锚定材料（AMS），因为它们可以强烈吸附并有效地抑制多硫化物物种的迁移。本文中，我们使用了基于第一原理的密度功能理论（DFT）计算来研究AMS（例如二核苷剂，WX2（X = S和SE）和Lips等AMS之间的相互作用。发现WS2和WSE2的嘴唇结合行为非常相似。计算出的嘴唇物种的吸附能表明WX2具有中等的结合强度，并且通过从多硫化物到AM的电荷转移来促进结合。我们观察到嘴唇内分子内LI-S键在WX2上的吸附后的伸长，但是，嘴唇的化学结构在没有分解的情况下保留。计算出的状态密度表明，与原始的WX2相比，嘴唇吸附的WX2系统表现出半导体行为，带隙略低。总体而言，我们的仿真结果为WX2的行为提供了详细的见解，因为AMS抑制了嘴唇迁移，因此为开发高性能LI-S电池铺平了道路。
The commercial realization of lithium-sulfur (Li-S) batteries is obstructed because of rapid capacity fading due to lithium polysulfides (LiPSs) dissolution into the electrolyte. In order to enhance the efficiency and performance of the Li-S batteries, the transition metal dichalcogenides are reported as promising anchoring materials (AMs) as they could strongly adsorb and effectively suppress the migration of the polysulfides species. Herein, we used first-principles based density functional theory (DFT) calculations to investigate the interactions between AMs such as tungsten dichalcogenides, WX2 (X=S and Se) and the LiPSs. The LiPSs binding behavior of WS2 and WSe2 are found to be quite similar. The calculated adsorption energies of LiPS species indicate that the WX2 possesses moderate binding strength and the binding is facilitated via charge transfer from the polysulfides to the AM. We observe elongation of intramolecular Li-S bonds in LiPS upon their adsorption onto the WX2, however, chemical structures of LiPSs are preserved without decomposition. The calculated density of states indicates the LiPS adsorbed WX2 systems exhibits semiconducting behavior with a slightly lower bandgap compared to the pristine WX2. Overall, our simulation results provide detailed insight into the behavior of WX2 as AMs to suppress the LiPSs migration and henceforth paves the way towards the development of high-performance Li-S batteries.
