Synthesis of microporous carbon/graphene composites for high-performance supercapacitors

•Microporous carbon/graphene composites (MPC/Gs) were made for the first time.•The surface area of the MPC/G composite materials reaches as high as 2233 m2 g− 1.•The MPC/G electrodes show high capacitance, good rate performance and stability.•This work paves a novel way to produce high performance composite materials.

Microporous carbon/graphene composites (MPC/Gs) are prepared for the first time directly from coal tar pitch and graphene oxide by KOH activation. MPC/Gs are characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and nitrogen adsorption-desorption techniques. The electrochemical properties of MPC/G composites are examined by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. MPC/G10-2-24 made with the mass ratio of coal tar pitch, graphene oxide and KOH at 10/2/24 possesses both high surface area and good electrochemical performance. When evaluated as electrodes of supercapacitors, MPC/G10-2-24 exhibits high specific capacitance (278 F g− 1 at 0.05 A g− 1), good rate performance (218 F g− 1 at 20 A g− 1) and excellent cycle stability (93% capacitance retention after 10,000 cycles). This work paves a facile method to produce composite materials, which is believed to be of interest for a wide audience of readers in the fields of energy conversion and storage.

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