posted on 2017-03-03, 00:00authored byRodrigo
Villegas Salvatierra, Dante Zakhidov, Junwei Sha, Nam Dong Kim, Seoung-Ki Lee, Abdul-Rahman O. Raji, Naiqin Zhao, James M. Tour
Here
we show that a versatile binary catalyst solution of Fe3O4/AlOx nanoparticles
enables homogeneous growth of single to few-walled carbon nanotube
(CNT) carpets from three-dimensional carbon-based substrates, moving
past existing two-dimensional limited growth methods. The binary catalyst
is composed of amorphous AlOx nanoclusters
over Fe3O4 crystalline nanoparticles, facilitating
the creation of seamless junctions between the CNTs and the underlying
carbon platform. The resulting graphene-CNT (GCNT) structure is a
high-density CNT carpet ohmically connected to the carbon substrate,
an important feature for advanced carbon electronics. As a demonstration
of the utility of this approach, we use GCNTs as anodes and cathodes
in binder-free lithium-ion capacitors, producing stable devices with
high-energy densities (∼120 Wh kg–1), high-power
density capabilities (∼20,500 W kg–1 at 29
Wh kg–1), and a large operating voltage window (4.3
to 0.01 V).