A smart bottom-up strategy for the fabrication of porous carbon nanosheets containing rGO for high-rate supercapacitors in organic electrolyte

•Porous carbon nanosheets containing rGO was obtained by a smart bottom-up strategy.•Solution process for dispersion of pitch without involving strong corrosive acids or harmful solvents.•The obtained samples show large specific surface area and uniform micropore size distributions.•The prepared product exhibits robust capacitive performance in organic electrolyte.

Exploration of various porous carbon materials with enhanced electrochemical performance is critical for the development of long-term sustainable energy storage and production systems. Herein, we have designed a smart bottom-up strategy to transformation of pitch into porous carbon nanosheets containing rGO (reduced graphene oxides) (PCSG) through a soft solution process coupling with KOH activation. This efficient solution process without involving hard templates or harmful solvents, which is clearly different from all the previously reported process, opening a new route towards porous carbons for energy storage applications. Notably, the as-obtained PCSG-60 sample (synthesized from 60 mg of GO) presents an optimum integration of a large specific surface area of 2217 m2/g, uniform micropore size (∼1.5 nm), and sheet-like morphologies. When evaluated as electrode materials for supercapacitor in 1 M TEABF4/AN electrolyte, the PCSG-60 exhibits excellent capacitive performance including large specific capacitances of 221 F/g (at 1 A/g), considerable rate capability (71.9% capacitance retention from 1 A/g to 50 A/g), smaller IR drop (0.637 V at 50 A/g), good cycling stability (91.8% of the initial capacitance after 3000 cycles at 10 A/g) and an energy density up to 38.2 Wh/kg even at an ultrahigh power density of 40500 W/kg, which puts the PCSG-60 among the best electrochemical performance in the reported pitch-derived carbon electrodes for supercapacitors. The outstanding capacitive electrochemical performance combined with the low-cost and readily accessible precursors enable the PCSG-60 is a promising electrode material for supercapacitor and other electrochemical energy storage system applications.

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