Investigation of the Li–S Battery Mechanism by Real-Time Monitoring of the Changes of Sulfur and Polysulfide Species during the Discharge and Charge

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• 作者：Dong Zheng ; Dan Liu ; Joshua B. Harris ; Tianyao Ding ; Jingyu Si ; Sergei Andrew ; Deyu Qu ; Xiao-Qing Yang ; Deyang Qu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2017
• 出版时间：February 8, 2017
• 年：2017
• 卷：9
• 期：5
• 页码：4326-4332
• 全文大小：474K
• ISSN：1944-8252

文摘

The mechanism of the sulfur cathode in Li–S batteries has been proposed. It was revealed by the real-time quantitative determination of polysulfide species and elemental sulfur by means of high-performance liquid chromatography in the course of the discharge and recharge of a Li–S battery. A three-step reduction mechanism including two chemical equilibrium reactions was proposed for the sulfur cathode discharge. The typical two-plateau discharge curve for the sulfur cathode can be explained. A two-step oxidation mechanism for Lib>2b>S and Lib>2b>Sb>2b> with a single chemical equilibrium among soluble polysulfide ions was proposed. The chemical equilibrium among Sb>5b>^2–, Sb>6b>^2–, Sb>7b>^2–, and Sb>8b>^2– throughout the entire oxidation process resulted for a single flat recharge curve in Li–S batteries.