▎ 摘　　要

To control the packing surface density of carbon nanotubes (CNTs) and the defects and numbers of graphene layers, graphene is grown on nickel foil by chemical vapor deposition (CVD) with different time periods and flow rates of methane. CNTs are then grown on the cobalt-coated (by sputtering of Co with different time) graphene/nickel foil prepared by CVD. Longer sputtering time for cobalt leads to lower capacitance of carbon nanotube/graphene composites. Furthermore, shorter growing time of graphene results in higher capacitance of carbon nanotube/graphene composites. Higher flow rates of methane for CVD lead to higher capacitance of carbon nanotube/graphene composites. (C) The Electrochemical Society of Japan, All rights reserved.