Nanowire Batteries

While many feared that GM was a something of the past, they released what promises to be the vehicle of the future. They are ironically the same company that tried to squash the electric car, but they’re making huge strides towards redeeming themselves with the new Chevrolet Volt. The plug-in electric hybrid features a revolutionary propulsion system that permits the car to cover over 64 km without using any gas whatsoever (the average Canadian commutes 67km to and from work). Of course for longer distances the car runs on a gas tank, which serves to recharge its batteries rather than running its engine. Which brings us to the heart, literally, of the electric car: the battery.

Keeping the batteries charged for as long as possible is the ultimate goal for any electric care company. Electric cars use rechargeable lithium-ion batteries, known as Li-ion batteries. Well, Dr. Yi Cui and his colleagues at Stanford University’s Department of Materials Science and Engineering have discovered a method to increase the charge of Li-ion batteries tenfold! In an article written by Dan Stober of the Stanford News Service, he describes how Dr. Yi Cui employs nanotechnology to give batteries ten time more juice:

The electrical storage capacity of a Li-ion battery is limited by how much lithium can be held in the battery’s anode, which is typically made of carbon. Silicon has a much higher capacity than carbon, but also has a drawback.

Silicon placed in a battery swells as it absorbs positively charged lithium atoms during charging, then shrinks during use (i.e., when playing your iPod) as the lithium is drawn out of the silicon. This expand/shrink cycle typically causes the silicon (often in the form of particles or a thin film) to pulverize, degrading the performance of the battery.

Cui’s battery gets around this problem with nanotechnology. The lithium is stored in a forest of tiny silicon nanowires, each with a diameter one-thousandth the thickness of a sheet of paper. The nanowires inflate four times their normal size as they soak up lithium. But, unlike other silicon shapes, they do not fracture.

So far we’ve only been looking under the hood for innovations in automotive greenery, now its time to check out the body.