Three dimensional few layer graphene and carbon nanotube foam architectures for high fidelity supercapacitors
By Wang, Wei; Guo, Shirui; Penchev, Miroslav; Ruiz, Isaac; Bozhilov, Krassimir N.; Yan, Dong; Ozkan, Mihrimah & Ozkan, Cengiz S.
Published in Nano Energy
2013
Abstract
Supercapacitors are promising alternative energy storage systems due to their relatively fast rate of energy storage and delivery. We describe a simple and scalable method to fabricate three-dimensional (3D) few-layer graphene/multi-walled carbon nanotube (MWNT) hybrid nanostructures on industrial grade metal foam foils (nickel foam) via a one-step ambient pressure chemical vapor deposition (APCVD) process. The as-grown few-layer graphene/MWNT nanocarbon foams are in the form of a homogeneous and densely packed hierarchical nanostructures and possess a very large surface area of 743 m2 g-1. Symmetrical electrochemical double-layer capacitors (EDLCs) of 3D hybrid hierarchical few-layer graphene/MWNT nanostructures show a high specific capacitance of 286 F g-1 which leads to an energy density of 39.72 Wh kg-1 and a superior power density of up to 154.67 kW kg-1. Moreover, the capacitance retention of 99.34% after 85000 charge–discharge cycles demonstrates the very high stability of the electrode architectures for supercapacitors. These merits enable the innovative 3D hierarchical few-layer graphene/MWNT foam to serve as high performance EDLC electrodes, resulting in energy storage devices with very high stability and power density.