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

Abstract

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 60mg of GO) presents an optimum integration of a large specific surface area of 2217m2/g, uniform micropore size (∼1.5nm), and sheet-like morphologies. When evaluated as electrode materials for supercapacitor in 1M TEABF4/AN electrolyte, the PCSG-60 exhibits excellent capacitive performance including large specific capacitances of 221F/g (at 1A/g), considerable rate capability (71.9% capacitance retention from 1A/g to 50A/g), smaller IR drop (0.637V at 50A/g), good cycling stability (91.8% of the initial capacitance after 3000 cycles at 10A/g) and an energy density up to 38.2 Wh/kg even at an ultrahigh power density of 40500W/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.