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NEC has used carbon
nanotube technology to build a fuel cell with 10 times the
energy density of today's most advanced batteries, which could
be used for powering mobile phones and portable computers.
Working with the Japan
Science and Technology Corporation and the Institute of Research
and Innovation, NEC has used one type of nanotube, a 'carbon
nanohorn', to construct the electrodes in the fuel cell.
NEC has been working on
the technology since the discovery of the tube-like structures
by one of its research fellows,
Sumio Iijima,
in 1991. He extended the work to the nanohorns three years ago.
The main characteristic of
the carbon nanohorns is that when they group together an
aggregate (a secondary particle) of about 100nm is created. This
creases an electrode with a very large surface area where gas
and liquid can permeate, increasing the efficiency of the
polymer electrolyte fuel cell developed at NEC. The nanohorn
structure also means that smaller particles platinum can be used
as a catalyst, again giving greater efficiency and increasing
the reliability of the cell.
The solid type polymer cell, based around a
fluoride polymer film as an electrolyte, operates at room
temperatures unlike other fuel cells and is also lightweight,
with an energy-conversion efficiency of 50%; more than double
that of today's batteries.
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