It's finally nice to see that it may materialize in the not-too-distant future.
Alternative energy storage devices (though it would be almost impossible in a laptop) include flywheels. That is what we should be thinking about for cars, instead of hydrogen (potentially as much a contributor to Global Warming as fossil fuels. Hydrogen LOVES to react with elements and create new baddies).
Today, they make them out of high-strength, lightweight, advanced composites which allows them to spin at speeds of up to 100,000 RPM. Older metal flywheels would fly apart under their own weight in the low thousands. Also as opposed to metal, they have sort of a bult-in failsafe if they are in an accident. At such high speeds, the material essentially vaporizes in its container if it comes unseated.
Just read about a potential new fuel cell development that provides power for laptops. Stranger things have happened I guess.