The latest breakthrough: a "nanopore" that's the ultimate in miniaturization. It's a hole in a ceramic sheet, no thicker than a grain of salt, that contains all the components a battery needs to produce electric current. One billion of these holes, connected in a honeycomb fashion, could fit on a postage stamp.

The itty-bitty battery delivers. It fully charges in 12 minutes and recharges thousands of times, according to University of Maryland researchers, who published their findings last week in the peer-reviewed journal Nature Nanotechnology.

"We were blown away by the performance," says co-author Eleanor Gillette, a doctoral candidate in chemistry. She attributes its quick charging to the short distances needed to carry the electric current. She says the nanosizing