New Technology May Bring Moore’s Law to Electrical Storage
We’ve learned to take the continued improvement in semiconductor manufacturing for granted. Computers, once only affordable to governments and large institutions, have invaded our homes, and now our pockets. Most of us walk around with processing power in the palms of our hands that qualified for supercomputer status just 30 years ago.
While electronic circuits continue to march relentlessly toward greater power and smaller scale, that is not also true of other parts that make mobile computing work. When it comes to batteries, we are still stuck with a technology that hasn’t delivered the performance improvements we are used to seeing with other technologies. Batteries have hardly improved at all.
This creates a bottleneck in a lot of fields, not just mobile computing. Electric cars, for example, depend on batteries to provide the stored energy needed to drive. Electric vehicle ranges, however, are sorely lacking, and the time required to recharge a battery is inconvenient when you compare it with filling up a gas tank.
Battery-powered vehicles have proven less than safe, as well. Some electric car models are notorious for catching on fire and batteries are a suspect. Recently, the entire fleet of Boeing’s new 787 jets has been grounded because of a lithium-ion battery fire hazard. It appears we are hitting physical limits to what is possible with electrochemically storing energy.
Recently discovered materials, however, could change that. Nobel Prize-winning discoveries made in 2004 showed that graphene could be extracted from bulk graphite. Graphene — a sheet of chemically attached carbon atoms only one molecule thick — is a material with astonishing physical and electrical properties. This sheet of carbon atoms, arranged in a honeycomb shape, is one of the strongest materials known and is very flexible. As one of the best conductors of electricity ever discovered, it also has the potential to upend the energy storage market.
Researchers at the University of California, Los Angeles Kaner Laboratory are working on fashioning supercapacitors using graphene as the electrodes. Capacitors, like batteries, are used to store an electrical charge. But capacitors do so by using a charge of static electricity, instead of an electrochemical process. With a capacitor, a sandwich is built using two electrodes surrounding an electrolytic material. As voltage is applied across the electrodes, an electrical potential builds and is stored by the device.
The way the UCLA research team, led by Richard Kaner, is producing graphene is shockingly simple. A solution of graphite oxide in a water solution is coated onto a sheet of plastic in the form of a compact disc. It is then inserted into a common, off-the-shelf optical disk drive and exposed to the drive’s laser. The process yields flexible graphene. Like the original “Scotch tape” method that won its inventors a Nobel Prize, this method is more like something you’d expect from a garage tinkerer than a prestigious university — but it works!
The graphene is then fashioned into tiny supercapacitors. Unlike batteries, capacitors can be charged quickly, and can discharge at an equally rapid rate. The graphene supercapacitors enjoy an energy density far higher than standard capacitors and lithium-ion batteries.
Moreover, unlike batteries, graphene supercapacitors can be charged and discharged over thousands of cycles without degrading. Future applications for this technology could be found in smartphones, laptops and vehicles. A future laptop computer could run for days on a single charge, instead of just hours.
Ad lucrum per scientia (toward wealth through science),
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