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

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/G(10-2-24) 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/G(10-2-24) 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. (C) 2016 Elsevier B.V. All rights reserved.