Nanoball Batteries Could Charge Electric Cars in 5Minutes
March 12th, 2009 by Lisa Zyga
A sample of the new battery material that could allow quickcharging of portable devices. Image credit: Donna Coveney.
(PhysOrg.com) -- Researchers at MIT have designed a new batterythat can recharge devices about 100 times faster than conventionallithium ion batteries. The design could lead to electric carbatteries that charge in 5 minutes (compared with 8 hours intoday's electric cars) and cell phone batteries that charge in just10 seconds.
Byoungwoo Kang and Gerbrand Ceder of MIT have improved the designof a "nanoball battery,"which has a cathode that iscomposed of nanosized balls of lithium iron phosphate. As thebattery charges, the nanoballs release lithium ions that travelacross an electrolyte tothe anode. As the battery discharges, the opposite occurs, and thelithium ions are reabsorbed by the nanoballs in the cathode.
The key to the nanoball battery's quick charge time is the speed atwhich the lithium iron phosphate nanoballs in the cathode canrelease and absorb lithium ions. In conventional lithium ion batteries, detaching the ions from the normal cathode takes a relatively long time. By coating each nanoball with a thin layer of lithium phosphate, Kang and Ceder showed that they could detach the lithium ions from the nanoballs even quicker than previous studies have found.
To demonstrate the technology, the researchers fabricated a smallbattery that could be fully charged or discharged in 10 to 20seconds, which would otherwise have taken six minutes. Thescientists' tests showed that the new material degrades less thanother battery materials after repeated charges and discharges. Thismeans that the battery could be made with less material, whichcould possibly lead to smaller, lighter batteries.
More information: Byoungwoo Kang and Gerbrand Ceder."Battery materials for ultrafast charging and discharging." Nature 458,190-193 (12 March 2009),