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

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 carbonbased 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.