3D hierarchical carbons composed of cross-linked porous carbon nanosheets for supercapacitors

• Published in: Journal of power sources Vol. 474; p. 228698
• Main Authors: Wei, Feng, He, Xiaojun, Bi, Honghui, Jiao, Shuai, Xiao, Nan, Qiu, Jieshan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 31.10.2020
• Subjects: 3D hierarchical carbons; Directing confinement template; Fluorene; High voltage window; Supercapacitors; Supercapacitors; Directing confinement template; Fluorene; 3D hierarchical carbons; High voltage window
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2020.228698

3D hierarchical porous carbons with good electric conductivity and excellent physicochemical stability are of great potential as electrode materials for supercapacitors. Herein, we report a directing-confinement-template strategy for synthesis of 3D hierarchical carbons composed of cross-linked porous carbon nanosheets from fluorene molecules. The 3D cross-linked networks serve as highways for electron conduction while the multi-level pore structures function as channels for fast ion transport with abundant active sites for ion adsorption. Benefiting from the above merits, the hierarchical carbons manifest a high gravimetric capacitance of 344 F g−1 at 0.05 A g−1, a superb rate capability with the capacitance up to 278 F g−1 even at 100 A g−1 and an outstanding cycle stability with only 0.7% decay after 50,000 cycles in alkaline electrolyte. Remarkably, hierarchical carbon-based capacitor displays a high energy density of 31.9 Wh kg−1 in 3 M ZnSO4 neutral electrolyte owing to the wide voltage window of 2.2 V. This work opens up a new avenue for designing hierarchical carbons via directing and confinement template approach from small aromatic molecules for high-performance energy storage devices. [Display omitted] •3D hierarchical carbons (HCs) composed of cross-linked nanosheets were synthesized.•The obtained HCs possess high surface area and multi-level pore structures.•The HC electrodes feature high specific capacitance and superb rate capability.•HC capacitors display high energy density of 31.9 Wh kg−1 in neutral electrolyte.