21st COE Seminar Series

1
21st COE Seminar Series 3 Department of
Materials Engineering The University of Tokyo
A Molten Salt Route for the Production of Carbon
Nanotubes by Dr. George Z. Chen Department of
Materials Science and Metallurgy, University of
Cambridge Pembroke Street, Cambridge CB2 3QZ,
UK Email gzc20_at_hermes.cam.ac.uk Tel
44-(0)1223-762965 Fax [phone]
May 28, 2003 1000- 1st Conference Room,
Institute of Industrial Science (????????1???)
Soon after the discovery, carbon nanotubes (CNTs)
attracted worldwide attention due to their unique
quasi-molecular structures and remarkable
material properties. The initial desired use of
these conductive and strong nanotubes were in
miniature devices, typically in the electrical
and mechanical areas. However, recent
development in research also shows a promising
future for using these nanotubes in bulk
quantities to enable much improved electron
conduction in conventional polymers, energy
conversion and storage, catalysis for targeted
chemical processes and etc. In particular, it
has been demonstrated that supercapacitors based
on carbon nanotubes exhibit unprecedented high
capacitance (high pulsed power) and long cycle
life. This development is very welcomed by, for
example, manufacturers of electric cars that are
currently put on hold by the incapability of fuel
cells and batteries to deliver power greater than
1 W/cm2 (electrolyte membrane).   At present,
carbon nanotubes are mainly produced, in the gas
phase, by two methods electric arc assisted
carbon vaporisation, and catalytic decomposition
of gaseous hydrocarbon at elevated temperatures.
The former produces relatively defect free and
hence straight CNTs, while the latter is featured
by its flexibility in producing either bent CNTs
in bulk quantities or aligned arrays standing on
an appropriate substrate, both being much purer
than the electric arc product. Nonetheless, the
production cost of the two methods are far from
being acceptable for bulk quantity use. In
additional to the high energy input (electric arc
method) or use of relatively expensive starting
materials (catalytic method), the fact that the
products from the two methods come out of the gas
phase adds another hurdle to introduce further
improvement.   This presentation reviews a newly
developed electrolytic method for the production
of CNTs in molten salts. First discovered in the
UK in mid 1990's, research in this method is
gathering forces around the world. In
particularly, it has been shown recently that,
once being scaled up, the electrolytic method has
the potential to significantly reduce the cost
for the production of CNTs. Also included in
this presentation are a historical view of the
electrolytic method, the basic experimental
set-up, characteristics of electrolytic CNTs and
other carbon nano-materials, electrochemical
studies of the process and a comparison of
different formation mechanisms.
Organizer Prof. Toru H. OKABE http//okabe.iis.u-
tokyo.ac.jp Tel [phone] For
registration contact Ms. Miyako YUKIYOSHI E-mail
yukiyosi_at_iis.u-tokyo.ac.jp
COE committee in Department of Materials
Engineering