'World's smallest' fuel cell for portable devices In
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Chủ nhật, 11 Tháng 1 2009 10:18

New Scientist has reported that the world's smallest working fuel cell has been created by US chemical engineers, at just 3 millimetres across. Future versions of the tiny hydrogen-fuelled power pack could replace batteries in portable gadgets. "It's not practical to make a pump, a pressure sensor, and the electronics to control the system in such a small volume," says Saeed Moghaddam at the University of Illinois at Urbana-Champaign. "Even if they are magically made at that scale, their power consumption would probably exceed the power generated."

Moghaddam, along with the team of Illinois colleague Mark Shannon, has come up with a design for a tiny fuel cell that generates power without consuming it. The new device has just four components. A thin membrane separates a water reservoir above from a chamber containing metal hydride below. Beneath the metal hydride chamber there is an assembly of electrodes.
The new micro fuel cell is just 3 mm by 3 mm (Image: Saeed Moghaddam)

Tiny holes in the membrane allow the water molecules to reach the adjacent chamber as vapour. Once there, the vapour reacts with the metal hydride to form hydrogen, which fills the chamber, pushing the membrane upwards and blocking the flow of water (see image, top right).
The hydrogen is gradually depleted, though, as it reacts at the electrodes beneath the chamber to create a flow of electricity. And when the hydrogen pressure drops, more water can enter to keep the reaction going.


Sources: http://www.newscientist.com/article/dn16370-worlds-smallest-fuel-cell-promises-greener-gadgets.html

Lần cập nhật cuối ( Chủ nhật, 11 Tháng 1 2009 10:29 )