One of our pet peeves is the short life of the rechargeable lithium ion batteries that power everything from our digital cameras to our laptops. We spend endless hours charging and recharging them for what we think is a pathetic amount of operating time. But at long last, some exciting and joyful news on the lithium ion battery front! Those wonderful geeks at Stanford University have found a way to increase battery life tenfold. Yes, that's right -- soon, those batteries will last ten times longer than they do now.
The researchers have found a way to use silicon nanowires to give rechargeable lithium ion batteries--used in laptops, iPods, video cameras, and mobile phones--as much as 10 times more charge. This potentially could give a conventional battery-powered laptop 40 hours of battery life, rather than 4 hours.
The new batteries were developed by assistant professor Yi Cui and colleagues at Stanford University's Department of Materials Science and Engineering.
"It's not a small improvement," Cui said. "It's a revolutionary development."
Citing a research paper they wrote, published in Nature Nanotechnology, Cui said the increased battery capacity was made possible though a new type of anode that utilizes silicon nanowires. Traditional lithium ion batteries use graphite as the anode. This limits the amount of lithium--which holds the charge--that can be held in the anode, and it therefore limits battery life.
Silicon anodes have the "the highest theoretical charge capacity" according to Cui's paper, but they expand when charging and shrink during use: a cycle that causes the silicon to be pulverized, degrading the performance of the battery. For 30 years, this dead end stumped researchers, who poured their battery life-extending energy into improving graphite-based anodes.
Cui and his colleagues looked at this old problem and overcame it by constructing a new type of silicon nanowire anode. In Cui's anode, the lithium is stored in a forest of tiny silicon nanowires, each with a diameter that is a thousandth of the thickness of a sheet of paper. The nanowires inflate to four times their normal size as they soak up lithium, but unlike previous silicon anodes, they do not fracture.
Ah, the old "forest of tiny silicon nanowires" trick -- we should have known that was the answer. The head scientist is looking for a deal with a major battery maker (that shouldn't be hard to find) and hopes to have it on the market in a few years. Major kudos to Yu Cui and his group for creating something that is going to be so useful.
