Electrical engineers at the Massachusetts Institute of Technology (MIT) have formed carbon molecules into tiny springs that store as much electricity as same sized lithium-ion batteries but can maintain a charge while dormant for years and work well in temperature extremes. Stanford University researchers have created ink made from carbon nanotubes that can be drawn onto paper where it serves as a high-capacity rechargeable energy storage medium. And University of Maryland scientists have created nanostructures able to store and transport power at 10 times the energy density of lithium-ion batteries.

Other technologies in development include batteries using zinc-air, lithium-air and other combinations of elements to provide longer run-times between recharges. Others still are working on prototype nuclear batteries, the trick being to make them small enough to be practical, let alone safe.

Of course, the accelerating growth of nanotechnology itself, which has not yet been thoroughly tested to evaluate potential down sides, has some health advocates worried. Animal studies have shown that some nanoparticles, if inhaled or ingested, can harm the lungs and also cross the blood-brain barrier, which protects the brain from toxins in the bloodstream.

And then there are fuel cells, created in 1839 but only recently commercialized. Not batteries per se, fuel cells generate, store and dispense power by forcing a reaction between a fuel (hydrogen from water, methanol) and oxygen, creating usable non-polluting electricity. One major hurdle for fuel cell makers is making them small enough to be able to work in laptops and other small personal electronics.