Whereas fuels typically are burned to create energy, fuel cells convert fuel into electricity through chemical reactions. In the case of Motorola's prototype, the fuel in question is methanol, the same stuff that powers race cars in the Indianapolis 500. Fuel cells also are far more efficient than most energy sources, and they're non-polluting and easily rechargeable. But until now, they've been far too large and expensive for use in portable devices.
"We're trying to see how small we can get an entire fuel-cell system," says Jerry Hallmark, manager of Motorola's energy technology lab. The prototype device is roughly the size of a deck of cards and could last five times longer than a standard battery. Hallmark says it will probably be two or three years before all the kinks are worked out and we see cheap, commercially available fuel cells powering portable devices.
But before that happens, Hallmark says, we will probably see hybrid systems that power devices using regular batteries recharged by a fuel cell. A cell phone powered with such a hybrid system could easily operate for more than a month, he says, before the user would need to pop in a fresh cartridge of methanol.