Kim Hun, Bang Sangin, Min Kyeong-Jun, Ham Young-Geun, Park Seong-Jin, Sun Yang-Kook
Department of Energy Engineering, Hanyang University, Seoul 04763, South Korea.
ACS Appl Mater Interfaces. 2021 Aug 25;13(33):39435-39445. doi: 10.1021/acsami.1c10756. Epub 2021 Aug 11.
To realize lithium-sulfur (Li-S) batteries with high energy density, it is crucial to maximize the loading level of sulfur cathode and minimize the electrolyte content. However, excessive amounts of lithium polysulfides (LiPSs) generated during the cycling limit the stable operation of Li-S batteries. In this study, a high-loading S cathode with a three-dimensional (3D) network structure is fabricated using a simple pelletizing method, and the exhausting overcharging phenomenon, which occurs in the high-loading Li-S cell, is successively prevented by pretreating the lithium metal anode. Moreover, adding a diluent to the electrolyte containing viscous LiPSs enables the facile conversion between S species during the cycling of high-loading Li-S cells under lean electrolyte conditions. Finally, a prototype Li-S pouch cell with high energy density (427 Wh kg) was realized by combining a compacted 3D cathode with a high-loading, pretreated thin lithium metal and diluent-modified electrolyte. We believe that the results reported herein will be a good guideline to establish proper strategies to achieve high energy density Li-S batteries.
为了实现具有高能量密度的锂硫（Li-S）电池，最大化硫正极的负载水平并最小化电解质含量至关重要。然而，循环过程中产生的过量多硫化锂（LiPSs）限制了Li-S电池的稳定运行。在本研究中，采用简单的造粒方法制备了具有三维（3D）网络结构的高负载硫正极，并且通过对锂金属负极进行预处理，相继防止了高负载Li-S电池中出现的过充耗尽现象。此外，在含有粘性LiPSs的电解质中添加稀释剂，能够使高负载Li-S电池在贫电解质条件下循环期间硫物种之间实现 facile 转化。最后，通过将压实的3D正极与高负载、经过预处理的薄锂金属以及稀释剂改性的电解质相结合，实现了具有高能量密度（427 Wh kg）的Li-S软包电池原型。我们相信本文报道的结果将为建立实现高能量密度Li-S电池的适当策略提供良好的指导。
