The prototype, which is the size of a CD-ROM, was demonstrated at the CeBit trade show here on Thursday. The company also showed off a prototype 12W fuel cell for notebook PCs and a prototype fuel cell charger for cell phones.
Commercial versions of the prototypes for notebooks and mobile handheld devices are expected to be available by late 2005.
Fuel cells are the next generation of battery technology and are being developed to extend the battery life of mobile devices.
Devices such as mobile phones, notebook computers, cameras, PDAs and MP3 players tend to use lithium-ion batteries, which experts claim are approaching the limit of their capacity.
Fuel cells, which generally use alcohols for fuel, can offer up to five to 10 times the power per unit weight of a lithium-ion battery, according to hardware suppliers such as Fujitsu.
Although experts agree that fuel cells have the potential to mark a significant step forward in battery performance, much of the promise of the technology is still theoretical.
Joseph Reger, the chief technology officer of Fujitsu Siemens, which is also developing fuel cells, said that one of the main drawbacks with fuel cells is safely refilling them. "You have to refuel it by injection," he said. "As it uses methanol, which is hazardous substance, there is an issue with that."
Millennium Cell, a New Jersey company, recently showed off a fuel cell based on hydrogen rather than methanol at the Intel Developer Forum in San Francisco. Methanol provides less energy than hydrogen--which is why most developers are aiming fuel cells at low-energy devices like MP3 players--but it is easier to store.
Ingrid Marson of ZDNet UK reported from Hannover.