Mechanism of Enhanced Carbon Cathode Performance by Nitrogen Doping in Lithium鈥揝ulfur Battery: An X-ray Absorption Spectroscopic Study

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• 作者：Pengyu Zhu ; Jiangxuan Song ; Dongping Lv ; Donghai Wang ; Cherno Jaye ; Daniel A. Fischer ; Tianpin Wu ; Yongsheng Chen
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：April 17, 2014
• 年：2014
• 卷：118
• 期：15
• 页码：7765-7771
• 全文大小：395K
• 年卷期：v.118,no.15(April 17, 2014)
• ISSN：1932-7455

文摘

Lithium鈥搒ulfur batteries have drawn much attention in advanced energy storage development due to their high theoretical specific capacity; however, several obstacles hinder their applications, including rapid capacity loss due to dissolution of polysulfide into the electrolyte. Nitrogen-doped mesoporous carbon cathode materials were found to effectively immobilize sulfur species and minimize the sulfur loss. In this work, we use X-ray absorption near-edge structure (XANES) spectroscopy to probe the coordination structures of C, O, and N in a carbon cathode before and after the sulfur loading in order to better understand the effects of nitrogen doping. A significant change in oxygen coordination structure is observed, whereas the carbon and nitrogen chemical environments remain unaltered. In addition, the significant change in S K-edge XANES spectra is also observed after sulfur was loaded on nitrogen-doped carbon cathode material. These observations reveal that strong interaction between the nitrogen-doped carbon and sulfur is through oxygen functional groups, and nitrogen doping probably makes oxygen functional groups more reactive toward sulfur.