Breakthrough promises faster charging of anything from cellphones to cars.
One of the downsides of a life that depends on battery-powered gadgets could be about to get better. Researchers have developed a battery that charges up to 100 times faster than existing types, yet will last just as long.
If it makes the transition from lab to commercial production successfully
it could mean cellphones that charge in seconds and laptops with batteries that are replenished in minutes.
The battery's greatest potential, however, could be in electric cars. If the cars were faster to recharge, one of the main obstacles to getting more of them on the roads would vanish.
The battery is the result of a decade's work by researchers under Paul Braun at the University of Illinois. Their results were described in the online journal Nature Nanotechnology in March, catching the attention of technology media.
All batteries consist of two electrodes - an anode and a cathode - which are connected by a conductor, or electrolyte. When we're yabbering away on our cellphones, negatively charged electrons are flowing through the phone's circuitry from the anode to the cathode. Positive ions go through the electrolyte from anode to cathode to balance the charge at both electrodes.
The secret to speedy recharging, which involves sending electrons and ions in the reverse direction, is to maximise the contact between electrolyte and electrode by using a thin material with a large surface area. But a small volume of active material also means little energy-storage capacity.
Braun and colleagues have used nanotechnology to get both: their technique - which is equally applicable to the lithium-ion battery of a cellphone or laptop and the nickel-metal hydride type found in Toyota's Prius - creates a 3D structure that has both the volume needed for energy storage and a large surface area for quick charging.
As he told the BBC, the structure enables them to "get electrons in and out of the battery much faster" - not through any new material but by changing the way the battery is assembled.
"What we build looks like a three-dimensional honeycomb, and that honeycomb is designed to allow everything to move fast. And because things move fast, we can make a battery that you can charge in seconds instead of minutes to hours."
If there's scepticism about the design, it's about whether what Braun has managed to do in the lab can be mass-produced.
In the lab they begin by coating a surface with a lattice of tightly packed tiny spheres, filling the space between and around the spheres with metal. The spheres are then melted or dissolved, leaving a porous 3D metal scaffolding.
By a process called electropolishing, the pores are enlarged to make an open framework that is coated with a thin film of active material.
According to the researchers, all the lab processes are used in industry and could be scaled up for battery manufacturing.
But MIT's Technology Review magazine reports that Jeff Dahn, professor of physics at Canada's Dalhousie University, is doubting whether commercial products would ever result. "When you look at the flow chart for making this structure it's pretty complicated, and that is going to be expensive," he said.
Braun can see the batteries having a future in electric cars, although "that's going to be down the road, so to say".
"Potentially you could have a car that pulls up to the equivalent of a petrol station and in a matter of minutes refill the battery and drive away." Ian Wright, a Kiwi electric-vehicle pioneer based in Silicon Valley, California, thinks battery affordability and limited range are bigger obstacles than recharging to getting more electric cars on the roads.
"A new fast-charge battery won't make any difference, unless it is also a very cheap fast-charge battery, which is not likely."
Wright, maker of the X1 high-performance electric car, says that fast-charge batteries will require a lot of power to be delivered to charging stations, which is technically feasible but not economic. Nor is the Braun group's battery unique, says Wright, with Nevada company Altairnano making similar performance claims for a nano-structured lithium titanate battery.
Braun plans to start small, making cellphone and laptop power packs, because of the manufacturing challenges of producing automotive batteries.
"The technology in the lab has worked exceptionally well and we're quite excited about it ... the step now is to scale this up and do it in large quantities," he said.
The United States Army Research Laboratory and the Department of Energy, which have been funding Braun's work, will be hoping he succeeds. So might the rest of us.
Anthony Doesburg is an Auckland technology journalist
