Fabrication and Characterization of 3-D Graphene-CNT Architectures Towards Supercapacitor Applications

Y.-S. Kim, K. Kumar, X. Li, F.T. Fisher, E.H. Yang
Stevens Institute of Technology, US

Keywords: graphene, CNT, 3-D architectures, supercapacitor


This work describes the first steps towards fabrication and characterization of a novel hybrid nanostructure comprised of carbon nanotubes (CNTs) grown out-of-plane from graphene layers for supercapacitor applications. Graphene is a promising material for supercapacitors, due to outstanding theoretical specific surface area (~2630 m2/g), and an intrinsic capacitance of up to 21 μF/cm2, the theoretical limit of carbon materials. The key idea of this work is to minimize graphene self-aggregation by growing CNTs spacers directly on and between the graphene layers. To this end, we have fabricated a CNT-graphene architecture, in which CNTs were grown out-of-plane on a graphene layer. The measured average capacitance of a graphene-CNT sample was 653.7 μF/cm2 at 10 mV/s. The graphene-CNT capacitance was maintained at 490.3 μF/cm2 at charging/discharging rates of 300 mV/s, implying very rapid current response on voltage reversal at each end potential. This indicates that there is a stable, low-resistance electric interconnection between CNTs grown on a non-aggregated graphene layer. The growth of novel graphene-CNT and graphene-CNT-graphene architectures is a milestone towards fabricating structures of alternating graphene and CNTs layers for 3D hybrid electrode architecture.