That's the promise of a new battery developed by researchers at MIT's Laboratory for Electromagnetic and Electronic Systems. They're using nanotechnology to improve an energy storage device called an ultracapacitor.

Nanotubes: (Photo courtesy Riccardo Signorelli, Laboratory for Electromagnetic and Electrical Studies, MIT)

Unlike regular batteries, which can generate electricity from a chemical reaction, capacitors store energy as an electrical field. Ultracapacitors can store lots of energy for a long time, but they need to be much bigger than regular batteries to hold the same amount of electricity. The new MIT technique, uses nanotechnology to improve the storage capacity of existing capacitors and may eventually help to make them smaller.

How does it work?

A battery has two electrodes, or terminals, one positive and one negative. Inside the battery are chemicals that react with each other to produce electrons. The electrons collect on the negative terminal of the battery. When you connect the terminals with a wire, you can use the flow of electrons to power things. A capacitor also has two electrodes-metal plates separated by a material that doesn't conduct electricity. A positive charge builds up on one plate, and a negative charge builds up on the other. When you connect the two electrodes, they discharge their energy. A battery can actually "create" energy by changing chemicals into electricity while a capacitor can only store energy it has been charged with.

Ultracapacitor in a hybrid engine: An ultracapacitor in a hybrid gas/electric engine for a car.

Today's ultracapacitors use electrodes made of activated carbon; the carbon is porous, so it has lots of surface area for the electrons to build up on. But the pores are irregular in size and shape, which reduces efficiency. That's why capacitors have to be big. But the MIT ultracapacitor has electrodes of vertically aligned carbon nanotubes, each one thirty-thousandth the width of a human hair. The regular shape and alignment of the nanotubes greatly increases the surface area, making the ultracapacitor very efficient at storing electrons.

Carbon nanotubes: Vertically aligned carbon nanotubes have lots of surface area to store electrons. (Photo courtesy Riccardo Signorelli, Laboratory for Electromagnetic and Electrical Systems, MIT)

Smaller is better

Ultracapacitors are long lasting and quick-charging. Storing energy at the atomic level with nanotubes means that they can finally be small, too, perhaps eventually powering everything from flashlights and cell phones to hybrid cars and missile-guidance systems.

Make it at the Museum

Stop by the Museum on Saturday, February 18th. You can make a pop can flashlight and test some conventional batteries. Experiment with electricity, circuits, and capacitors more at the AC/DC electricity bench in the Experiment Gallery.

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