New rechargeable battery runs on gas

A new fuel cell technology that will let laptop users type away for 12 to 15 hours longer than today's batteries has been announced.

US-based Medis Technologies is working on a refuellable cartridge using its direct liquid methanol (DLM) fuel cells. The cells exploit a range of alcohols or mixture of alcohols as fuel without reducing the performance or longevity of the cell.

A fuel cell is an electrochemical device which combines hydrogen fuel with oxygen to produce electric power, heat and water.

In many ways, the fuel cell resembles a battery. But instead of applying a periodic recharge, a continuous supply of oxygen and hydrogen is supplied from the outside.

Oxygen is drawn from the air and hydrogen is carried as a fuel in a pressurised container.

Medis executives say its new technology will recharge in seconds and will cost less to use than conventional batteries.

Robert Lifton, chairman and chief executive of Medis, said ultimately every mobile phone and every laptop would use fuel cells. "It's obvious that no-one will be able to compete in that market unless they have a fuel cell," he said.

At a recent conference, Medis presented fuel cells operating on ethanol (an alcohol) that performed at the highest level of its methanol fuel cells.

According to Medis, the use of the special architecture that prevents fuel migration to the cathode, and the use of its liquid electrolyte instead of a Proton Exchange Membrane, are part of its advanced DLM fuel cell technology that makes the results possible.

Lifton said an ethanol fuel cell would resolve all the questions raised about the safety of methanol and the ability to carry methanol-bearing products on airplanes and elsewhere.

"The use of ethanol in fuel cells is totally safe and, of course, can generally be transported without restriction."

According to battery consultant firm Huret Associates, fuel cells may soon compete with batteries for portable applications, such as laptop computers and mobile phones.

But Barry Huret, president of Huret Associates, also warned that today's technologies have limitations in meeting the cost and size criteria for small portable devices.

In addition, the cost per watt-hour is less favourable for small systems than large.