But capacitors contain energy as an electric field of charged particles created by two metal electrodes. Capacitors charge faster and last longer than normal batteries. The problem is that storage capacity is proportional to the surface area of the battery's electrodes, so even today's most powerful capacitors hold 25 times less energy than similarly sized standard chemical batteries.
The researchers solved this by covering the electrodes with millions of tiny filaments called nanotubes. Each nanotube is 30,000 times thinner than a human hair. Similar to how a thick, fuzzy bath towel soaks up more water than a thin, flat bed sheet, the nanotube filaments increase the surface area of the electrodes and allow the capacitor to store more energy. Schindall says this combines the strength of today's batteries with the longevity and speed of capacitors.
"It could be recharged many, many times perhaps hundreds of thousands of times, and ... it could be recharged very quickly, just in a matter of seconds rather than a matter of hours," he says.
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Schindall thinks hybrid cars would be a particularly popular application for these batteries, especially because current hybrid batteries are expensive to replace.
