Graphene and single-walled carbon nanotubes are carbon materials that exhibit excellent
electrical conductivities and large specific surface areas. Theoretical work suggested that a
covalently bonded graphene/single-walled carbon nanotube hybrid material would extend
those properties to three dimensions, and be useful in energy storage and nanoelectronic
technologies. Here we disclose a method to bond graphene and single-walled carbon
nanotubes seamlessly during the growth stage. The hybrid material exhibits a surface area
42,000m2 g1 with ohmic contact from the vertically aligned single-walled carbon
nanotubes to the graphene. Using aberration-corrected scanning transmission electron
microscopy, we observed the covalent transformation of sp2 carbon between the planar
graphene and the single-walled carbon nanotubes at the atomic resolution level.
These findings provide a new benchmark for understanding the three-dimensional graphene/
single-walled carbon nanotube-conjoined materials.