Silicon compound aims to superconduct at room temperature
R. Colin Johnson/ EE Times/ (03/17/2008 5:35 PM EDT)
PORTLAND, Ore. — A new superconducting material fabricated by a
Canadian-German team has been fabricated out of a silicon-hydrogen
compound. Instead of super-cooling the material, as is necessary for conventional superconductors,
the new material is instead super-compressed. The researchers claim
that the new material could sidestep the cooling requirement, thereby
enabling superconducting wires that work at room temperature.
"Our research in this area is aimed at improving the critical
temperature for superconductivity so that new superconductors can be
operated at higher temperatures, perhaps without a refrigerant," said
Tse.
He performed the theoretical work with doctoral candidate Yansun Yao.
The experimental confirmation was performed by researcher Mikhail
Eremets at the Max Planck Institute in Germany.
The new family of superconductors are based on a hydrogen
compound called "silane," which is the silicon analog of
methane--combining a single silicon atom with four hydrogen atoms to
form a molecular hydride. (Methane is a single carbon atom with four
hydrogens).
Researchers have speculated for years that hydrogen under enough pressure
would superconduct at room temperature, but have been unable to achieve
the necessary conditions (hydrogen is the most difficult element to
compress). The Canadian and German researchers attributed their success
to adding hydrogen to a compound with silicon that reduced the amount
of compression needed to achieve superconductivity.
Tse's team is currently using the Canadian Light Source
synchrotron to characterize the high pressure structures of silane and
other hydrides as potential superconducting materials for industrial
applications as well as a storage mechanism for hydrogen fuel cells.
The research was funded by the National Sciences and
Engineering Research Council of Canada, the Canada Research Chairs
program, the Canada Foundation for Innovation and the Max Planck
Institute.
(Editor's Note: This is a slightly corrected version of the
original story, which intimated that the silicon compound was tested at
room temperature. It was not. However, nor was it "supercooled," so it
is expected to lead to room-temperature superconductivity in the
future.)
Source: Silicon compound superconduct
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Findings Could Improve Fuel Cell Efficiency
Researchers at Duke’s Pratt School of Engineering have developed a
membrane that allows fuel cells to operate at low humidity and
theoretically at higher temperatures.
A new type of membrane based on tiny iron
particles appears to address one of the major limitations exhibited by
current power-generating fuel cell technology.
While there are many types of fuel cells, in
general they generate electricity as the result of chemical reactions
between an external fuel -- most commonly hydrogen -- and an agent that
reacts with it. The membrane that separates the two parts of the cell
and facilitates the reaction is a key factor in determining the
efficiency of the cell.
Fuel cells are commonly used in such settings as satellites,
submarines or remote weather stations because they have no moving
parts, do not require combustion and can run unattended for long
periods of time. However, current fuel cells lose efficiency as the
temperature rises and the humidity falls.
Researchers at Duke University’s Pratt School of Engineering have
developed a membrane that allows fuel cells to operate at low humidity
and theoretically to operate at higher temperatures. They reported
their findings online in the Journal of Membrane Science.
...
Full story: http://www.physorg.com/news125157863.html
