Chemical vapor deposition-grown carbon nanotubes/graphene hybrids for electrochemical energy storage and conversion

Chemical vapor deposition (CVD)-grown carbon nanotubes (CNTs)/graphene hybrids produce a novel three-dimensional carbon composite structure with seamless C-C junctions of one-dimensional CNTs and two-dimensional graphene. The CNTs/graphene hybrids promote the advantages of their building blocks, exhibiting large surface area, high electrical conductivity, excellent mechanical and chemical stability. Hence they are becoming an ideal electrode material platform for electrochemical energy storage and conversion including supercapacitors, lithium batteries and fuel cells. In this review, we first summarize the CVD growth for the fabrication of three types of CNTs/graphene hybrids, including CNTs/graphene oxide, CNTs/planar graphene and CNTs/graphene foam. And then we discuss the applications of CVD-grown CNTs/graphene hybrids in supercapacitors, lithium batteries and fuel cells. Finally, we propose the challenges and opportunities in future development of the CNTs/graphene hybrids.