As more and more portable electronics go "wireless," at least one component of the technology is struggling to keep up with the advances: the power source. As any user of wireless wonders knows, you still need to periodically plug the batteries into a bulky recharger-or simply throw them out. Polyfuel, a tiny spinoff from Palo Alto, Calif.'s SRI International, could change all that with a scaled-down version of the same fuel cells being developed to power cars and trucks (see "Fill 'er Up with Hydrogen").

Polyfuel's dainty power plants can serve up the trickle of electricity needed to operate a personal digital assistant or cell phone, and the company is promising commercial products within a year that will supply continuous power for five times longer than today's best lithium-ion batteries. "If SRI can make this work then God bless them," says Milosz Skrzypczak, a consumer electronics analyst at The Yankee Group, a market research firm in Boston. "I'll be happy to stop charging my phone every couple of days." The technology behind SRI's tiny fuel cells is a variant of the proton exchange membrane (PEM) cells slated for automobile engines. But unlike the PEM cells used in cars, these smaller versions consume methanol rather than hydrogen gas; as a result they can be refueled quickly and inexpensively. Pop in a cartridge of concentrated methanol the size of an AA battery, and these electrochemical devices could, in principle, deliver juice for up to two weeks of phoning.