A team of researchers at the Massachusetts Institute of Technology have discovered a new way to store electrical energy and a paper on their research was published this week in Nature.
Gerbrand Ceder, an R. P. Simmons Professor of Materials Science and Engineering, and his team at MIT's Computational and Experimental Design of Emerging Materials Research group have found a way to demonstrate how batteries, which obtain high energy density by storing a charge in the bulk of a material, can also reach super-high discharge rates.
What they have developed are battery cells that charge up in seconds. The rates are similar to those of supercapacitors, which are similar to regular capacitors with the exception that they offers a very high charge in a small package.
Nearly five years ago, Ceder and colleagues made a surprising discovery. Computer calculations of a well-known battery material, lithium iron phosphate, predicted that the material's lithium ions should actually be moving extremely quickly.
The researchers, whose work was supported by the National Science Foundation and the U.S. Department of Energy, began experimenting with how lithium ions move in and around lithium iron phosphate, a material used in lithium-ion batteries. Through computer calculation of lithium iron phosphate, the researchers predicted the material's lithium ions would move more quickly from one area to another.
Their discovery of a way to charge and discharge batteries in seconds instead of hours may lead to new technology applications, according to Ceder and MIT graduate student Byoungboo Kang.
Storage of electrical energy at a high charge and discharge rate is significant for several technologies and could change the landscape of batteries produced for laptops and other technological devices. One technology that would benefit, but with limitations, is green technology. The high charge and discharge rate will enable hybrid and plug-in hybrid-electric vehicles and provide backup for wind and solar energy.
Until now, researchers believed high power rates in electrical systems could only be reached with supercapacitors. But Ceder said he and his team discovered a way to get a common lithium compound to take in lithium ions in seconds.
Smaller and Lighter
Cedar and Kang said such short cycles could mean lifestyle changes. They wrote, "Such changes may first take place in the use of small devices, where the total amount of energy stored is small."
Aside from speed, Ceder and Kang also found that after repeated discharges and recharges, batteries made with their material degraded less than lithium-ion batteries. The researchers think their batteries could be produced with less material, ultimately making them smaller and lighter.
Ceder and Kang also think that because the material they used is not new -- they simply changed the way they make it -- their research could arrive in the marketplace in as little as two or three years.