Portable Fuel Cells: Coming Soon?

A California start-up has made an advance that it says stands to make Direct Methanol Fuel Cells--envisaged as a future power source for mobile electronics devices--smaller, cheaper, and lighter.

PolyFuel's development of a new Direct Methanol Fuel Cell (or DMFC) membrane comes as several of the world's largest electronics companies are developing fuel cells with a view to commercializing them later this year or next year.

The membrane is a small piece of plastic that looks something like sandwich wrap, according to PolyFuel President and CEO Jim Balcom. It sits at the heart of the DMFC separating a mixture of methanol and water from a catalyst. It's the electrical potential across the membrane that is the key to power creation however the current most popular membrane isn't well suited for use in DMFC applications, Balcom says.

"Until now all of the manufacturers, and we've counted 35 organizations working on DMFCs, have been hampered because they have had to use a hydrogen fuel cell membrane that was developed 40 years ago. It has been the only one available for DMFC applications and they are very different technologies," he says.

Increased Concentration

The biggest problem developers have is stopping methanol crossing over the membrane--something that lowers overall efficiency of the fuel cell because fuel is wasted and it also results in generation of heat. To combat this problem researchers have kept methanol concentrations relatively low, at around 10 percent although a higher concentration would be better, says Balcom.

His company's new membrane allows for much higher concentrations--between 50 percent and 100 percent--and this should mean DMFCs can be made one-third smaller, lighter, and less expensive, he says.

Increasing the methanol concentration has been a stated goal of several companies developing DMFCs for some time.

Product Plans

NEC, which plans to commercialize a DMFC for notebook computers this year, is currently using a methanol concentration of around 10 percent in its prototype, and Toshiba, which has shown a prototype battery charger based on DMFC technology, says it uses a concentration of between 3 percent and 6 percent.

Hitachi plans a DFMC for use in PDAs and says it hopes to raise methanol concentration from around 20 percent to 30 percent by the time the produce is commercialized in 2005.

PolyFuel's new membrane is already in sample production and initial feedback from the company's potential clients is good, says Balcom. The company's current production capacity in Silicon Valley is anticipated to be enough to handle customer demand though 2005 and further expansion will be based on demand, he says.

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