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").

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