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(epoxy compatible sizing). To grow CNTs on the carbon fibers, an Fe(C
5
H
5
)
2
(fer-
rocene) catalyst was applied to the samples fiber bundles using thermal chemical
vapor deposition (CVD) in vacuum. Prior to the application of the catalyst, the
carbon fiber bundles were heat treated at 750°C for an hour in vacuum to remove
the sizing. The growth temperature and time for CNTs deposition were selected
as 750°C(T1000GB) and 700°C (K13D) for 900 s.
1.1.6.6 CNT-AC COMPOSITE
Among various advanced functional materials, electronically conducting poly-
mers (such as polypyrrole (PPy) and polyaniline (PANI)) and metal oxides (such
as RuO
2
, MnO
2
, NiO, and Co
3
O
4
) are widely used in super-capacitors. However,
their applications are severely limited by their poor solubility and mechanical brit-
tleness. Anchoring the conductive polymers or metal oxides to cellulose fibers or
other textile fibers has inspired the design of their paper or textile based compos-
ites which show excellent cycling stability, mechanical flexibility and robustness.
However, the textile fibers are usually insulators. Advanced carbon materials,
such as carbon nanotubes (CNTs), graphene, ordered mesoporous carbon, carbon
aerogels, hierarchical porous carbon, carbide-derived carbon, and their compos-
ites/hybrids, have been widely explored for use as super-capacitor electrodes. The
carbon materials can also be combined with conductive polymers or metal oxides
to obtain flexible CNT/PANI, carbon nanofiber (CNF)/PANI, graphene/PANI or
graphene oxide/PANI, or CNT/CuO composite electrodes with improved electro-
chemical performance. Very recently, bi-scrolling nanotube sheets and functional
guests into yarns, which contained up to 95 wt.% of otherwise unspinnable par-
ticulate or nanofiber powders, has been used to fabricate yarns for use in super-ca-
pacitors and lithium on battery materials. However, the large-scale production of
inexpensive, flexible electrode remains a great challenge. Super-capacitors with
AC/CNT nanocomposite electrodes have been shown to exhibit enhanced elec-
trochemical performance compared with CNT-free carbon materials, although the
original CNTs were strongly entangled with each other, and acid purification was
always required. As a result, those CNTs well dispersed in the electrode were too
short to form a self-supporting network. The as-obtained AC/CNT nanocompos-
ites were still in powder form, and a binder was still needed. Recently it has been
shown that vertically aligned CNTs, in which the CNTs with large aspect ratio are
well oriented, can be well dispersed into individually long CNTs by a two-step
shearing strategy. They also obtained CNT pulp, in which long CNTs have good
dispersion in the liquid phase, can be used as a feedstock for CNT transparent
conductive films and Bucky paper. As a result of great efforts to mass-produce
aligned CNTs, they can be easily produced by radial growth on spheres or inter-
calated growth in lamellar catalysts. In this contribution, industrially produced
aligned CNTs, together with AC powder, were used as raw materials to fabricate
flexible electrodes. It is expected that the CNTs will bind AC particles together to
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