Controllable growth of CNTs on graphene as high-performance electrode material for supercapacitors

Design and synthesis of three-dimensional (3D) structured carbon materials are crucial for achieving high-performance supercapacitors (SC) for energy storage. Here, we report the preparation of 3D architectured GN-CNT hybrid as SC electrodes. Controllable growth of carbon nanotubes on graphene sheets was realized through a facile one-pot pyrolysis strategy. The length of the carbon nanotubes could be rationally tuned by adjusting the amount of precursors. Correspondingly, the resulted GN-CNT hybrid showed adjustable electrochemical performance as an SC electrode. Importantly, the GN-CNT exhibited a high specific surface area of 903 m² g^-1 and maximum specific capacitance of 413 F g^-1 as SC electrodes at a scan rate of 5 mV s^-1 in 6 M KOH aqueous solution. This work paves a feasible pathway to prepare carbon electrode materials with favorable 3D architecture and high performance, for use in energy storage and conversion.