Three-dimensional (3D) carbon networks have been explored as promising capacitive materials thanks to their unique structural features such as large ion-accessible surface area and interconnected porous networks, thus enhancing both ions and electrons transport. Here, sustainable bacterial cellulose (BC) is used both precursor and template for facile synthesis of free-standing N, S-codoped 3D carbon networks (a-NSC) by the pyrolysis and activation of polyrhodanine coated BC. The synthesized a-NSC shows highly conductive interconnected porous networks (24 S•cm-1), large surface area (1 420 m2•g-1) with hierarchical meso-microporosity, and high-level heteroatoms codoping (N: 3.1 % in atom, S: 3.2 % in atom). Benefitting from these, a-NSC as binder-free electrode exhibits an ultrahigh specific capacitance of 340 F•g-1 (24 μF•cm-2) at the current density of 0.5 A•g-1 in 6 M KOH electrolyte, high-rate capability (71% at 20 A•g-1) and excellent cycle stability. Furthermore, the assembled symmetrical supercapacitor displays a much short time constant of 0.35 s in 1 M TEABF4/AN electrolyte, obtaining a maximum energy density of 32.1 W•h•kg-1 at power density of 637 W•kg-1. The in situ multi-heteroatoms doping enables biocellulose-derived carbon networks to exploit its full potentials in energy storage applications, which can be extended to other dimensional carbon nanostructures.
|ジャーナル||Transactions of Nanjing University of Aeronautics and Astronautics|
|出版ステータス||Published - 2018 8月 1|
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