Zong Wei, Lai Feili, He Guanjie, Feng Jianrui, Wang Wei, Lian Ruqian, Miao Yue-E, Wang Gui-Chang, Parkin Ivan P, Liu Tianxi
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Innovation Center for Textile Science and Technology, Donghua University, Shanghai, 201620, P. R. China.
Christopher Ingold Laboratory, Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, UK.
Small. 2018 Aug;14(32):e1801562. doi: 10.1002/smll.201801562. Epub 2018 Jul 12.
The use of free-standing carbon-based hybrids plays a crucial role to help fulfil ever-increasing energy storage demands, but is greatly hindered by the limited number of active sites for fast charge adsorption/desorption processes. Herein, an efficient strategy is demonstrated for making defect-rich bismuth sulfides in combination with surface nitrogen-doped carbon nanofibers (dr-Bi S /S-NCNF) as flexible free-standing electrodes for asymmetric supercapacitors. The dr-Bi S /S-NCNF composite exhibits superior electrochemical performances with an enhanced specific capacitance of 466 F g at a discharge current density of 1 A g . The high performance of dr-Bi S /S-NCNF electrodes originates from its hierarchical structure of nitrogen-doped carbon nanofibers with well-anchored defect-rich bismuth sulfides nanostructures. As modeled by density functional theory calculation, the dr-Bi S /S-NCNF electrodes exhibit a reduced OH adsorption energy of -3.15 eV, compared with that (-3.06 eV) of defect-free bismuth sulfides/surface nitrogen-doped carbon nanofiber (df-Bi S /S-NCNF). An asymmetric supercapacitor is further fabricated by utilizing dr-Bi S /S-NCNF hybrid as the negative electrode and S-NCNF as the positive electrode. This composite exhibits a high energy density of 22.2 Wh kg at a power density of 677.3 W kg . This work demonstrates a feasible strategy to construct advanced metal sulfide-based free-standing electrodes by incorporating defect-rich structures using surface engineering principles.
独立式碳基复合材料的应用对于满足不断增长的能量存储需求起着至关重要的作用，但快速电荷吸附/解吸过程的活性位点数量有限，极大地阻碍了其发展。在此，展示了一种有效的策略，即制备富含缺陷的硫化铋与表面氮掺杂碳纳米纤维相结合（dr-Bi₂S₃/S-NCNF），作为用于不对称超级电容器的柔性独立电极。dr-Bi₂S₃/S-NCNF复合材料表现出优异的电化学性能，在1 A g⁻¹的放电电流密度下，比电容提高到466 F g⁻¹。dr-Bi₂S₃/S-NCNF电极的高性能源于其具有良好锚定的富含缺陷的硫化铋纳米结构的氮掺杂碳纳米纤维的分级结构。密度泛函理论计算表明，与无缺陷的硫化铋/表面氮掺杂碳纳米纤维（df-Bi₂S₃/S-NCNF）相比，dr-Bi₂S₃/S-NCNF电极的OH吸附能降低至-3.15 eV。进一步利用dr-Bi₂S₃/S-NCNF复合材料作为负极，S-NCNF作为正极制备了不对称超级电容器。该复合材料在功率密度为677.3 W kg⁻¹时，具有22.2 Wh kg⁻¹的高能量密度。这项工作展示了一种可行的策略，即利用表面工程原理引入富含缺陷的结构来构建先进的金属硫化物基独立电极。
