Self-Discharge Behavior of Lithium-Sulfur Batteries at Different Electrolyte/Sulfur Ratios
Self-Discharge Behavior of Lithium-Sulfur Batteries at Different Electrolyte/Sulfur Ratios
复制标题
DOI：
10.1149/2.0461903jes
复制
发表时间：
2019-01-02
影响因子：
3.9
通讯作者：
Zheng, Jim P.
中科院分区：
文献类型：
--
作者：
Shen, Chao;Xie, Jianxin;Zheng, Jim P.
锂硫电池循环性能差，容量衰减快，库仑效率低，自放电率高，阻碍了锂硫电池的商业化。与连续循环下的动态电化学稳定性相比，通常用自放电特性来描述锂硫电池的静态电化学稳定性的研究少得多。本文以独立式碳纳米管泡沫为阴极，进行了一组实验，旨在了解自放电过程与各种操作条件的相关性。我们发现自放电速率与放电深度和电解质/硫比有很强的依赖性。研究表明，自放电对锂硫电池后续放电容量的影响与电解质中多硫化锂的种类和浓度及其与锂阳极的相互作用密切相关。本文对这一关系进行了详细的分析，表明要提高锂硫电池的可循环性和容量，应特别注意自放电时的充电状态和其他运行条件。此外，我们还强调了有效的阳极保护对于提高这些电池的静态电化学稳定性的重要性。(C)作者2019。由ECS出版。这是一篇基于知识共享署名4.0许可协议的开放获取文章。
The commercialization of lithium sulfur (Li-S) batteries is hindered by their poor cycling performance, including fast capacity fade, low Coulombic efficiency, and high self-discharge rate. The static electrochemical stability of Li-S batteries, which is usually described in terms of their self-discharge properties, was much less studied compared to the dynamic electrochemical stability under continuous cycling. In this article, a set of experiments designed to understand the correlation between the self-discharge process and various operational conditions were made by using freestanding carbon nanotube foams as cathodes. We found a strong dependence of the self-discharge rate on the depth of discharge and on the electrolyte/sulfur ratio. We show that the effects of the self-discharge on the subsequent discharge capacities of Li-S cells are closely related to the type and concentration of lithium polysulfide species in the electrolyte and their interaction with the Li anode. This relation is analyzed in detail in this article, showing that one should pay special attention to the state-of-charge during self-discharge and the other operational conditions in order to improve the cyclability and capacity of Li-S batteries. In addition, we also highlight the importance of an efficient anode protection to improve the static electrochemical stability of these batteries. (C) The Author(s) 2019. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License.