Compact Fuel Cells Could Oust Batteries

ENERGY TECH

Fuel Cells Could Oust Batteries In Next Phase Of Micro Wars

where fuel cells are heading

London - Mar 04, 2004
Hot on the heels of a warning about the mounting energy demands of smart cellphones comes a ray of hope. Cellphone giant Nokia last week warned that battery technology is not keeping pace with advanced phone functions - but a trick that boosts the power of miniature hydrogen fuel cells by up to 50 per cent could help keep energy-hungry gadgets up and running reports New Scientist this week.

By shrinking the channels that deliver fuel to the cell's heart, mechanical engineers Suk Won Cha and Fritz Prinz at Stanford University in California have found they can dramatically increase the cell's efficiency.

The apparent downside is that the effect only works with hydrogen fuel cells, whereas liquid methanol is currently the fuel of choice for consumer electronics firms like Motorola and NEC that are developing fuel-cell-powered cellphones and laptops.

They favour methanol because it releases more energy than hydrogen, volume for volume, so methanol-powered gadgets would be able to have smaller "fuel tanks".

However, methanol is toxic, and the fuel cells that use it produce the greenhouse gas carbon dioxide as a waste product.

Hydrogen produces only water, and this, along with Cha's efficiency-boosting trick, could make it a strong contender for fuelling mobile devices.

Fuel cells work by combining the fuel with oxygen from the air and using the energy liberated to drive an electrical current. Cha's fuel cell contains a polymer-based "proton exchange membrane" sandwiched between an anode and cathode layer, each containing a platinum catalyst.

Hydrogen travels to the anode through a polymer block bored with channels 500 micrometres wide.

At the anode, the platinum helps break the hydrogen down into protons and electrons. The protons cross the membrane and react with oxygen and electrons from the cathode, and this drives the electrons left at the anode around an electrical circuit to the cathode.

The Stanford team decided to see what would happen if they made the channels smaller and more numerous.

They used a microchip etching process to bore channels just 20 micrometres wide. The effect was to increase the speed at which the hydrogen is delivered and prevent the anode being flooded with fuel.

This boosted the rate of proton exchange and increased the fuel cell's power by half as much again.

Standard laptop batteries can usually run for 2 to 4 hours without a recharge.

Some hydrogen fuel cell companies hope to produce cells that run up to 20 hours, says Cha, and he claims that his technique should increase the running time by as much as 50 per cent on top of that.

Or you could achieve the same running time for just 70 per cent of the fuel.

David Hart, head of fuel cell research at Imperial College London, says it should be possible to scale up the Stanford team's technique to build much larger fuel cells out of many smaller cells.

But Manfred Stefener, head of Smart Fuel Cells in Germany, is worried about waste water clogging the microchannels.

"The smaller you make your channels, the higher the risk of water getting stuck in that channel," he says. "This can be disastrous." Cha acknowledges the design will have to take account of this.

ENERGY TECH

Microbial Fuel Cell Cleans and Generates Power From Wastewater

University Park - Feb 25, 2004
Penn State environmental engineers have shown, for the first time, that a microbial fuel cell (MFC) can generate electricity while simultaneously cleaning the wastewater that you flush down the drain or toilet.

Thanks for being here; We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain. With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords. Our news coverage takes time and effort to publish 365 days a year. If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor $5 Billed Once credit card or paypal		SpaceDaily Monthly Supporter $5 Billed Monthly paypal only

The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.