Hierarchical "tube-on-fiber" carbon/mixed-metal selenide nanostructures for high-performance hybrid supercapacitors.

Author(s) Lv, L.P.; Zhi, C.; Gao, Y.; Yin, X.; Hu, Y.; Crespy, D.; Wang, Y.
Journal Nanoscale
Date Published 2019 Jul 16
Abstract

This work reports hierarchical "tube-on-fiber" nanostructures, composed of carbon nanotubes (CNTs) on carbon nanofibers (CNFs), impregnated with mixed-metal selenide nanoparticles (Co-Zn-Se@CNTs-CNFs), as high performance supercapacitors. Co-Zn hybrid zeolitic imidazolate framework-67 (Co-Zn ZIF-67) was electrospun with polyacrylonitrile (PAN) to form nanofibers that were sequentially thermally treated and subjected to selenylation. The "tube-on-fiber" structure is designed to confine the Co-Zn mixed-metal selenide nanoparticles and prevents their agglomeration. Extruded CNTs rooting in carbon nanofibers further improve the electronic conductivity. The mixed-metal selenide allows more accommodation space and faradic reactions compared to single metal selenide. Based on these merits, the hierarchical Co-Zn-Se@CNTs-CNFs exhibit a high specific capacity of 1040.1 C g-1 (1891 F g-1) at 1 A g-1 with impressive rate performance in supercapacitors. Furthermore, a hybrid supercapacitor with Co-Zn-Se@CNTs-CNFs as the cathode and porous carbon nanofibers as the anode (denoted as Co-Zn-Se@CNTs-CNFs//PCNFs) is fabricated. It delivers a superior energy and power density of 61.4 W h kg-1 and 754.4 W kg-1, respectively, and meanwhile retains 31.7 W h kg-1 of the energy density with 15 421.6 W kg-1 of the working power. In addition, the assembled supercapacitor device displays an excellent capacity retention of 88.6% after 8000 cycles at 5 A g-1.

DOI 10.1039/c9nr03088c
ISSN 2040-3372
Citation Lv L-, Zhi C, Gao Y, Yin X, Hu Y, Crespy D, et al. Hierarchical "tube-on-fiber" carbon/mixed-metal selenide nanostructures for high-performance hybrid supercapacitors. Nanoscale. 2019.

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