Superwetting monolithic carbon with hierarchical structure as supercapacitor materials

Monolithic hierarchically porous carbon (MHC) was prepared by a facile dual-templating approach with tri-block polymer F127 as the soft template and porous monolithic silica as the hard template. The surface of carbon materials was processed to improve the electrochemical properties via surface modification, the carbon materials would become hydrophilic. A series of properties were investigated by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Brunaner–Emmett–Teller measurement (BET), respectively. The electrocapacitive properties were evaluated by cyclic voltammetry and galvanostatic charge–discharge cycling in a three-electrode system. In an aqueous H2SO4 electrolyte, the specific capacitances of materials treated by nitric acid had dramatically increased from 282 to 320 F g−1, similarly, the specific capacitances of materials treated by sulfuric acid had improved to 404 F g−1. The series of MHC showed good cycling behaviors on specific capacitance which hardly decreased during 1000. The energy densities of MHC and modified MHC could reach up to 39.2 and 56.1 Wh kg−1, respectively when the power density was at 125 W kg−1. It was quite promising for this kind of materials to be far-reaching applied in the field of electrode materials for supercapacitor.

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► Monolithic hierarchically porous carbon was prepared by dual-templating approach.
► Hydrophilic carbon could be got after surface modification.
► The capacitance performance of modified materials had obvious shift from cyclic voltammetry and charge discharge test.
► The carbon materials showed good cycling behaviors and power performance.