Random Accesses

Ordinary paper can be turned into a battery electrode simply by dipping it into carbon-nanotube inks. The resulting electrodes, which are strong, flexible, and highly conductive, might be used to make cheap energy storage devices to power portable electronics.

It's now possible to print lightweight circuits and screens for electronics like e-readers, but conventional batteries still weigh these devices down. Carbon nanotubes are a promising material for printing batteries because, in addition to their strength, light weight, and conductivity, they can store a large amount of energy--a quality that helps portable electronics run longer between charges.

Now a group of Stanford University researchers, led by materials science professor Yi Cui, have demonstrated that ordinary office paper soaks up carbon nanotubes like a sponge and can be turned into electrodes for batteries and supercapacitors.

Source: http://www.technologyreview.com/energy/24097/?a=f

The human brain runs on only about 20 watts of power, equal to the dim light behind the pickle jar in your refrigerator. By contrast, the computer on your desk consumes a million times as much energy per calculation. If you wanted to build a robot with a processor as smart as the human brain, it would require 10 to 20 megawatts of electricity.

“Ten megawatts is a small hydroelectric plant,” Boahen says dismissively. “We should work on miniaturizing hydroelectric plants so we can put them on the backs of robots.” You would encounter similar problems if you tried to build a medical implant to replace just 1 percent of the neurons in the brain, for use in stroke patients. That implant would consume as much electricity as 200 households and dissipate as much heat as the engine in a Porsche Boxster.

“Energy efficiency isn’t just a matter of elegance. It fundamentally limits what we can do with computers,” Boahen says. Despite the amazing progress in electronics technology—today’s transistors are 1/100,000 the size that they were a half century ago, and computer chips are 10 million times faster—we still have not made meaningful progress on the energy front. And if we do not, we can forget about truly intelligent humanlike machines and all the other dreams of radically more powerful computers.

Source: http://discovermagazine.com/2009/oct/06-brain-like-chip-may-solve-computers-big-problem-energy/

Batteries can power anything from small sensors to large systems. While scientists are finding ways to make them smaller but even more powerful, problems can arise when these batteries are much larger and heavier than the devices themselves. University of Missouri researchers are developing a nuclear energy source that is smaller, lighter and more efficient.

Kwon and his research team have been working on building a small nuclear battery, currently the size and thickness of a penny, intended to power various micro/nanoelectromechanical systems (M/NEMS). Although nuclear batteries can pose concerns, Kwon said they are safe.

"People hear the word 'nuclear' and think of something very dangerous," he said. "However, nuclear power sources have already been safely powering a variety of devices, such as pace-makers, space satellites and underwater systems."

Source: http://www.physorg.com/news174139641.html

The production of graphene has just become a whole lot easier. Northwestern University scientists have demonstrated that graphite oxide can be converted instantly to graphene by exposing the material to a pulse of light from an ordinary camera flash.

Laura J. Cote, Rodolfo Cruz-Silva, and Jiaxing Huang of Northwestern report an instantaneous, chemical-free way to transform graphite oxide, an electrical insulator, into graphene, a conductor, at room temperature. The photographic camera flash instantaneously triggers the deoxygenation reaction of GO by photothermal heating.

Graphene is the one atom-thick wonder material that may some day replace silicon in electronics. Until recently, it has been difficult to produce.

Source: http://blogs.zdnet.com/emergingtech/?p=1659

Nanoscale sensors are exquisitely sensitive, very frugal with power, and, of course, tiny. They could be useful in detecting molecular signs of disease in the blood, minute amounts of poisonous gases in the air, and trace contaminants in food. But the batteries and integrated circuits necessary to drive these devices make them difficult to fully miniaturize. The goal of Zhong Lin Wang, a materials scientist at Georgia Tech, is to bring power to the nano world with minuscule generators that take advantage of piezoelectricity. If he succeeds, biological and chemical nano sensors will be able to power themselves.

The piezoelectric effect--in which crystalline materials under mechanical stress produce an electrical potential--has been known of for more than a century. But in 2005, Wang was the first to demonstrate it at the nanoscale by bending zinc oxide nanowires with the probe of an atomic-force microscope.

Source: http://www.technologyreview.com/energy/22118/