Sulfur/Polythiophene with a Core/Shell Structure: Synthesis and Electrochemical Properties of the Cathode for Rechargeable Lithium Batteries

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• 作者：Feng Wu ; Junzheng Chen ; Renjie Chen ; Shengxian Wu ; Li Li ; Shi Chen ; Teng Zhao
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：April 7, 2011
• 年：2011
• 卷：115
• 期：13
• 页码：6057-6063
• 全文大小：1011K
• 年卷期：v.115,no.13(April 7, 2011)
• ISSN：1932-7455

文摘

Novel sulfur/polythiophene composites with core/shell structure composites were synthesized via an in situ chemical oxidative polymerization method with chloroform as a solvent, thiophene as a reagent, and iron chloride as an oxidant at 0 掳C. Different ratios of the sulfur/polythiophene composites were characterized by elemental analysis, FTIR, XRD, SEM, TEM, and electrochemical methods. A suitable ratio for the composites was found to be 71.9% sulfur and 18.1% polythiophene as determined by CV and EIS results. Conductive polythiophene acts as a conducting additive and a porous adsorbing agent. It was uniformly coated onto the surface of the sulfur powder to form a core/shell structure, which effectively enhances the electrochemical performance and cycle life of the sulfur cells. The initial discharge capacity of the active material was 1119.3 mA h g^鈭?, sulfur and the remaining capacity was 830.2 mA h g^鈭? sulfur after 80 cycles. After a rate test from 100 to 1600 mA g^鈭? sulfur, the cell remained at 811 mA h g^鈭? sulfur after 60 cycles when the current density returned to 100 mA g^鈭? sulfur. The sulfur utilization, the cycle life, and the rate performance of the S鈭扨Th core/shell electrode in a lithium鈭抯ulfur battery improved significantly compared to that of the pure sulfur electrode. The pore and thickness of the shell affected the battery performance of the lithium ion diffusion channels.