US researchers power up world's smallest fuel cell
One millimetre thick fuel cell raises prospect of hydrogen powered mobile devices
Researchers at the University of Illinois have developed a fuel cell measuring just three milimetre square, raising the prospect of small water-powered fuel cells one day being used to provide zero carbon power for mobile phones and other handheld devices.
The 1mm thick unit currently generates just milliamp at 0.7 volts and could already be used to power microbots and simple electronics systems.
Historically, the size of fuel cells has been constrained by the need for the pump to deliver the external fuel supply, which has been a relatively power-hungry component.
However, the Illinois team have managed to dispense with the conventional fuel pumps and pressure sensors used in larger fuel cells by instead using surface tension to move water through the device.
The water feeds slowly through a membrane as vapour, and then reacts with a metal hydride to form hydrogen. The hydrogen reacts with an array of electrodes to form electricity, and as it depletes, more water flows through the membrane.
The small amount of energy generated by the cell means that it is currently unsuitable for today's personal consumer electronics such as mobile phones.
But because the cell uses surface tension rather than gravity to deliver the water, it means that the device can be rotated during use, making it suitable for other smaller mobile applications where electronics are being moved around.
The fuel cell was developed by researchers at the University including Saeed Moghaddam, Mark Shannon, and Richard Masel.
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