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Sulfur‐Deficient Bismuth Sulfide/Nitrogen‐Doped Carbon Nanofibers as Advanced Free‐Standing Electrode for Asymmetric Supercapacitors
Author(s) -
Zong Wei,
Lai Feili,
He Guanjie,
Feng Jianrui,
Wang Wei,
Lian Ruqian,
Miao YueE,
Wang GuiChang,
Parkin Ivan P.,
Liu Tianxi
Publication year - 2018
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201801562
Subject(s) - supercapacitor , materials science , carbon nanofiber , bismuth , electrode , carbon fibers , nanotechnology , chemical engineering , electrochemistry , composite number , carbon nanotube , composite material , chemistry , engineering , metallurgy
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 2 S 3 /S‐NCNF) as flexible free‐standing electrodes for asymmetric supercapacitors. The dr‐Bi 2 S 3 /S‐NCNF composite exhibits superior electrochemical performances with an enhanced specific capacitance of 466 F g −1 at a discharge current density of 1 A g −1 . The high performance of dr‐Bi 2 S 3 /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 2 S 3 /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 2 S 3 /S‐NCNF). An asymmetric supercapacitor is further fabricated by utilizing dr‐Bi 2 S 3 /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 −1 at a power density of 677.3 W kg −1 . This work demonstrates a feasible strategy to construct advanced metal sulfide‐based free‐standing electrodes by incorporating defect‐rich structures using surface engineering principles.