One-step approach for fabrication of 3D porous carbon/graphene composites as supercapacitor electrode materials

Abstract

In this work, we reported a facile one-step method for fabricating hierarchically porous carbon/graphene composites, which exhibited superior electrochemical performance in supercapacitor as electrode. The preparation was processed in a KCl molten salt at a temperature range of 650–950 °C using soluble low-molecular-weight phenolic resol as carbon source. The structural and morphological characterizations showed that composites possessed a special 3D structure, which consisted of well-dispersive porous carbon particles growing chemically on the graphene sheets. The carbon particles served as spacers to block the aggregation of graphene sheets. This unique structure benefited the penetration/mobility of ions within the composites due to high surface area, abundant micropores/mesopores/macropores, high conductivity of graphene, and strong chemical interaction between porous carbon particles and graphene. The optimal sample offered an outstanding capacitive behavior in the two-electrode and three-electrode system including higher specific capacitance, better rate capability and more stable cycling performance after 5000 cycles. This study opens up a new strategy for developing graphene based electrode material in supercapacitor.