Acta Chimica Sinica ›› 2022, Vol. 80 ›› Issue (7): 896-902.DOI: 10.6023/A22030117 Previous Articles     Next Articles

Article

金属有机框架衍生的空心碳纳米笼的结构调控与锂硫电池性能研究

何家伟, 焦柳, 程雪怡, 陈光海, 吴强*(), 王喜章, 杨立军, 胡征*()   

  1. 南京大学化学化工学院 介观化学教育部重点实验室 南京 210023
  • 投稿日期:2022-03-17 发布日期:2022-06-13
  • 通讯作者: 吴强, 胡征
  • 基金资助:
    国家自然科学基金(21832003); 国家自然科学基金(21972061); 国家重点研发计划(2021YFA1500900); 江苏省前沿引领技术基础研究专项(BK20212005)

Structural Regulation of Metal Organic Framework-derived Hollow Carbon Nanocages and Their Lithium-Sulfur Battery Performance

Jiawei He, Liu Jiao, Xueyi Cheng, Guanghai Chen, Qiang Wu(), Xizhang Wang, Lijun Yang, Zheng Hu()   

  1. Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023
  • Received:2022-03-17 Published:2022-06-13
  • Contact: Qiang Wu, Zheng Hu
  • Supported by:
    National Natural Science Foundation of China(21832003); National Natural Science Foundation of China(21972061); National Key Research and Development Program of China(2021YFA1500900); Natural Science Foundation of Jiangsu Province, Major Project(BK20212005)

Lithium-sulfur battery has attracted extensive research interest because of its high theoretical specific capacity, low cost and environmental friendliness. However, its practical application is still limited by the low utilization of sulfur, serious shuttle and polarization effects. To solve these problems, confining sulfur in a highly conductive host, with the assistance of chemical adsorption of intermediate lithium polysulfides (LiPS) by polar sites and catalytic promotion of LiPS conversion by catalytic sites, can effectively boost the charge transfer and suppress the shuttle and polarization effects, hence leading to the high utilization of sulfur and the improved performances of lithium-sulfur batteries. Hollow carbon nanocages have become an ideal host for sulfur encapsulation because of the large inner cavity, high conductivity, and tunable surface and electronic structures. In this study, three kinds of hollow carbon nanocages with similar size but different composition and structure of shells were prepared by etching the ZIF8, ZIF67 and ZIF8@ZIF67@ZIF8 precursors with tannic acid solution, followed by the carbonization. Used as the cathodes for lithium-sulfur batteries after sulfur filling, the sample derived from ZIF8@ZIF67@ZIF8 shows the best electrochemical performance. Specifically, the specific capacity reaches 1010 mAh•g-1 at 0.1 C (1 C=1675 mA•g-1), and remains 664 mAh•g-1 at 1 C; after 300 cycles tests at 0.5 C, the capacity is retained at 492 mAh•g-1, significantly better than the control samples derived from ZIF8 and ZIF67. The excellent performance of the former is closely related to its unique structure and composition: (ⅰ) the Co species presented in the precursor can improve the conductivity of derived carbon nanocages; (ⅱ) the evaporation of Zn species brings about large specific surface area and rich micro/mesopores, which is conducive to the sulfur filling and the catalytic conversion of S species by the active Co species. Therefore, the shuttle and polarization effects are efficiently suppressed and the utilization of sulfur is improved accordingly, leading to the better performances of lithium-sulfur batteries. This study opens a new avenue to regulate the performance of lithium-sulfur batteries by constructing novel carbon nanocages hosts based on the metal organic framework (MOF) precursors.

Key words: lithium-sulfur battery, cathode material, metal organic framework (MOF)-derived carbon nanocages, electrocatalysis, confinement effect