perfidy

Via slashdot, news that the big brains at MIT may have made a long-awaited breakthrough in battery technology. AS is often the case, they decided not to flail the dead horse of mature technology looking for incremental gains, but rather looked sideways - and in this case backwards to a
different model.

Conventional batteries rely on storing electrical energy as chemical energy. The reactions of the chemicals in your double AAs release that energy again as electricity. The problem with batteries is that over time, they lose the ability to store energy and must be discarded. The MIT boffins went back to another old energy storage technology, capacitors, and decided to give it a little boost by means of nanotechnology.

Capacitors store electrical energy as, well, electrical energy. Inside the capacitor, an electric field of charged particles stores that energy between two metal electrodes. They charge and discharge much faster than batteries, and last much longer than batteries. So why aren't we using them already? Storage capacity is proportional to the surface area of the batteries' electrodes, which limits the amount of energy you can store. For the same size, a capacitor can only hold a few percent of the energy of a battery. And that's where the nanotech comes in.

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 on 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.

Even getting capacitors up to the same energy storage of a battery would be an enormous leap. Plug your laptop into an outlet for a few seconds, and you're good for hours of use. And your capacitor won't fail after a year. Should this technology actually result in higher energy densities, the possibilities are rather amazing.

A battery or a high capacity capacitor is an energy bucket. You pour water in, you pour water out. But batteries have a lid with a small spout, and water eventually destroys the bucket. Quick discharge and high reliability means that energy weapons that we already know how to build become feasible. Quick recharge means that much of the technology that we use becomes much more usable. For a while there, it looked like methane fuel cells were the only way out of the battery problem, but this will be - if it lives up to the inventor's claims - an almost ideal solution.