氧烷
材料科学
碳纳米管
阴极
化学工程
催化作用
共轭微孔聚合物
聚合物
微型多孔材料
扫描透射电子显微镜
透射电子显微镜
纳米技术
化学
物理化学
有机化学
光谱学
复合材料
物理
量子力学
工程类
作者
Yuncan Jia,Wenbin Gong,Xueying Fan,Shang Chen,Xiaodong Meng,Yongqiang Meng,Ji Zhou,Yawen Cao,Song Hong,Lirong Zheng,Zhao Wang,Christopher W. Bielawski,Jianxin Geng
标识
DOI:10.1016/j.cej.2022.136546
摘要
Conjugated microporous polymers (CMPs) hold great potential for use in energy related applications due to their extended π-conjugated structures, tunable pore sizes, and modular molecular functionalities. Herein, we report a novel composite material (labeled as Co-CMP-MWNTs) that consists of a CMP containing Co single-atom catalysts (Co SACs) and being coaxially grafted to multi-walled carbon nanotubes (MWNTs), and show that the material synergistically promotes the cathode reaction kinetics in lithium−sulfur (Li−S) batteries. The Co-CMP-MWNTs are synthesized by coupling 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine to a dibromobipyridine-Co complex in the presence of bromopyrimidinyl-functionalized MWNTs. The composite features a conductive MWNT-based core and a CMP-based shell that contains nitrogen as well as Co. Cs-corrected high-resolution transmission electron microscopy and X-ray absorption near-edge structure (XANES) spectroscopy reveal that the Co species exist as single atoms. Additional XANES data coupled with density functional theory calculations elucidate the adsorption interactions formed between the Co SACs and various sulfur species as well as their electrocatalytic effects. Li−S cells prepared using Co-CMP-MWNTs as a cathode host material exhibit excellent performance in terms of specific capacity (1485 mA h g−1 at 0.1 C), rate capability (602 mA h g−1 at 3 C), and cycling stability (510 mA h g−1 at 0.5 C after 1000 cycles, which corresponds to a capacity decay of 0.050% per cycle). Collectively, the results demonstrate that SACs can be prepared under benign conditions and used to enhance sulfur cathode reaction kinetics. The methodology described may be extended to enable the use of SACs in other contemporary energy conversion technologies.
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