World’’s smallest fuel cell may pave way for eco-friendly portable gadgets

January 8th, 2009 - 1:41 pm ICT by ANI  

London, Jan 8 (ANI): Chemical engineers in the US have created the world’’s smallest working fuel cell, which may lead to the development of environmentally-friendly portable gadgets in future.

At just 3 millimetres across, future versions of the tiny hydrogen-fuelled power pack will be able to store more energy than batteries and that too in the same space.

Still, its easier to make batteries at the small scale than the pumps and control electronics of a fuel cell.

In fact, small pumps tend to utilise more energy than they generate.

“It’’s not practical to make a pump, a pressure sensor, and the electronics to control the system in such a small volume. Even if they are magically made at that scale, their power consumption would probably exceed the power generated,” New Scientist quoted Saeed Moghaddam at the University of Illinois at Urbana-Champaign as saying.

Thus, the researchers have now come up with a design for a tiny fuel cell that generates power without consuming it.

The new device is made up of just four components.

While a thin membrane separates a water reservoir above from a chamber containing metal hydride below, an assembly of electrodes lies beneath the metal hydride chamber.

The membrane has tiny holes that allow the water molecules to reach the adjacent chamber as vapour, which after reaching there reacts with the metal hydride to form hydrogen.

The hydrogen fills the chamber, pushing the membrane upwards and blocking the flow of water.

However, the hydrogen is gradually depleted by reacting at the electrodes beneath the chamber to create a flow of electricity.

As soon as the hydrogen pressure drops, it makes space for more water to enter and continue the reaction.

As the device is just 3 mm by 3 mm by 1 mm, it is the surface tension instead of gravity that controls the flow of water through the system.

Thus, the cell operates even if moved and rotated, making it ideal to power a pocket gadget.

According to Moghaddam, the latest designs give currents of around 1 milliamp at a similar voltage, which although is not enough to drive cellphones, but can power simpler electronic systems or microrobots. (ANI)

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