Stanford University researchers have made a discovery that could signal the arrival of laptop batteries that last more than a day on a single charge.
The researchers have found a way to use silicon nanowires to give rechargeable lithium-ion (Li-ion) batteries, used in laptops, iPods, video cameras and mobile phones, as much as 10 times more charge. This potentially could give a conventional Li-ion battery-powered laptop 40 hours of battery life, rather than four.
The new Li-ion batteries were developed by assistant professor Yi Cui and colleges at Stanford University's Materials Science and Engineering Department. "It's not a small improvement," Cui said. "It's a revolutionary development."
Citing their paper published in Nature Nanotechnology, Cui said the increased Li-ion battery capacity was made possible though a new type of anode that utilises silicon nanowires. Traditional Li-ion batteries use graphite as the anode, which limits the amount of lithium — which holds the charge — that can be held in the anode, and therefore limits battery life.
Silicon anodes have the "the highest theoretical charge capacity" according to Ciu's paper, but expand when charging and shrink during use: a cycle which causes the silicon to be pulverised, so degrading the performance of the battery. This dead end stumped researchers for 30 years, who instead poured their energy into improving graphite-based anodes in an effort to expand battery life.
Cui and his colleagues took 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 one-thousandth 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.
Cui said there a few barriers to commercialising the technology: "We are working on scaling up and evaluating the cost of our technology. There are no roadblocks for either of these."
Cui has filed a patent on the technology and is considering formation of a company or an agreement with a battery manufacturer. He expects the battery to be commercialised and available within "several years", pending testing.
Talkback
At last there appears to be a breakthrough in the battery usage life for our many varieties of laptop computers and devices. With a successful development of this battery the great drawback of mobile computing will virtually disappear.
But will this mean the almost demise of the desktop machine as we know it? Needs some pondering - and some fast and furious R&D from component manufacturers to be ready for the battery's arrival.
Ultimately this is a good thing for not just mobile computing, but (hopefully) many other power-hungry mobile appliances, like digital cameras/camcorders, PDAs, music/video players etc.
It would certainly revolutionise things from a convenience point of view - I would love to be able to use my digital camera for a week without recharging or having to carry another 2 sets of batteries around!
It may also push development of features that might otherwise be abandoned because of the power requirements. We have already seen this happen as a result of increasing capacity with normal rechargeables, e.g. larger LCD screens and optical zoom lenses on digital cameras - who knows what might be possible with a 5-10x increase in the capacity.
However, I don't think desktops will disappear as a result. They have their own advantages over laptops and firmly occupy a significant niche in the computing market.
If this makes it to commercial production it could be interesting!
Implications for range, power (speed) and cost are huge. Don't forget that once the range is above a normal long days driving, you don't any longer need to be able to recharge quickly.