A research group at the University of Illinois has developed technology that may have lasting implications for electric vehicles (EVs) and other electronics.
The group, led by Paul Braun, a professor of material sciences and engineering, has come up with technology that creates a much more rapid charging time for lithium-ion batteries, which power electronics like cellphones, laptops and defibrillators. Lithium-ion batteries also power EVs, which can take all night to charge at home and up to an hour to charge at EV stations.
Braun's findings, published last week in an online version of the journal Nature Nanotechnology, could lead to an EV charging time comparable to that for filling a tank of gas. Smaller objects like cell phones could charge in well under a minute, Braun said.
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"We have batteries in the lab that can charge in tens of seconds," he said.
When a battery charges, energy moves between its cathode and anode. When a battery powers a product, or discharges, energy travels the opposite way, between its anode and cathode. Braun's group came up with a three-dimensional nanostructure for the battery cathode that allows its batteries to charge at a much faster rate than conventional batteries.
Conventional lithium-ion or nickel metal hydride rechargeable batteries contain active material that is placed into a thin film. The thin film allows batteries to charge and recharge quickly, but at the cost of significant degrading over time. Because it's thin, the film doesn't allow for much energy storage. This lack of density causes the rapid degrading.
Braun's invention wraps the thin film around a 3-D structure that allows greater energy storage capacity while still rapidly charging and recharging. The 3-D structure is assembled by coating the surface with tiny spheres. The space between the spheres gets filled with metal. Both are then melted together, leaving a porous, sponge-like surface. Next, the pores get enlarged and the structure is coated with the thin film.
The nanostructure isn't immune to degrading, but this process is prolonged because its efficiency is 10 times greater than conventional batteries, Braun said. He also expects this greater efficiency will allow EV batteries to work better in cold temperatures, although his group hasn't conducted studies to verify this yet.
Getting EV batteries to charge as fast as it takes to fill a tank of gas requires a different infrastructure than what exists today, he said. Charging stations will need to offer sufficient power, but Braun said developing technology should eventually create an incentive for it.
Although the nanostructure makes the batteries 20 to 30 percent denser, Braun said the biggest improvement is the rapidity of the charging.
Braun's group worked for about two years on the nanostructure. Since the nanostructure is applied to a battery's cathode, he said, the next step is to study improving the anode, along with further increasing battery density.
Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500
