title: Graphene and carbon nanotube composite electrodes for supercapacitors with ultra-high energy density.
abstract: We describe a graphene and single-walled carbon nanotube (SWCNT) composite film prepared by a blending process for use as electrodes in high energy density supercapacitors. Specific capacitances of 290.6 F g(-1) and 201.0 F g(-1) have been obtained for a single electrode in aqueous and organic electrolytes, respectively, using a more practical two-electrode testing system. In the organic electrolyte the energy density reached 62.8 Wh kg(-1) and the power density reached 58.5 kW kg(-1). The addition of single-walled carbon nanotubes raised the energy density by 23% and power density by 31% more than the graphene electrodes. The graphene/CNT electrodes exhibited an ultra-high energy density of 155.6 Wh kg(-1) in ionic liquid at room temperature. In addition, the specific capacitance increased by 29% after 1000 cycles in ionic liquid, indicating their excellent cyclicity. The SWCNTs acted as a conductive additive, spacer, and binder in the graphene/CNT supercapacitors. This work suggests that our graphene/CNT supercapacitors can be comparable to NiMH batteries in performance and are promising for applications in hybrid vehicles and electric vehicles.
authors: National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, Japan.
authors: Qian
authors: Q
authors: Cheng
authors: Jie
authors: J
authors: Tang
authors: Jun
authors: J
authors: Ma
authors: Han
authors: H
authors: Zhang
authors: Norio
authors: N
authors: Shinya
authors: Lu-Chang
authors: LC
authors: Qin
mesh_terms: D004566:Electrodes; D006108:Graphite / Q000737:chemistry*; D008958:Models, Molecular; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D037742:Nanotubes, Carbon; D006108:Graphite