Supercapacitor could make electric car viable
Scientists at the Massachusetts Institute of Technology think they're on the verge of making traditional batteries obsolete.
The researchers are working on a new device that uses carbon nanotubes to store and release electrical energy in a system that could carry as much power as today's lead or lithium batteries.
But unlike the rechargeable batteries used on today's cellphones and laptop computers, these devices could be recharged hundreds of thousands of times before wearing out.
And instead of taking hours to recharge, they could be powered up in about the same time it takes to fill up a gas tank.
The device being developed at MIT's Laboratory for Electromagnetic and Electronic Systems isn't a battery, but a capacitor -- a device that's already used in nearly every electronic product on the planet. When plugged into an electrical circuit, a capacitor briefly stores incoming electricity, they releases it at a predictable rate. Capacitors can't store very much power, compared to traditional batteries. But while it takes hours to recharge a battery, capacitors charge almost instantly. And while most batteries can only be recharged a few hundred or thousand times before wearing out, capacitors can be recharged hundreds of thousands of times.
During the 1960s, scientists discovered that they could make more powerful capacitors by coating their electrodes with finely ground charcoal -- a form of carbon. The charcoal crystals greatly increased the surface area of each electrode, allowing it to collect a greater electrical charge.
Since then, scientists have learned how to grow carbon nanotubes -- extremely thin fibers of pure carbon. Schindall and his colleagues realized that millions of tiny nanotubes would do a much better job than ground charcoal in expanding an electrode's surface area. And if the nanotube-coated electrodes were made large enough, you could build a capacitor that could work like a battery with enough power to drive a device for hours.
