Posted on 03/11/2009 1:43:13 PM PDT by neverdem
Two researchers have developed battery cells that can charge up in less time than it takes to read the first two sentences of this article. The work could eventually produce ultra-fast power packs for everything from laptop computers to electric vehicles.
Byoungwoo Kang and Gerbrand Ceder of the Massachusetts Institute of Technology in Cambridge have found a way to get a common lithium compound to release and take up lithium ions in a matter of seconds. The compound, which is already used in the electrodes of some commercial lithium-ion batteries, might lead to laptop batteries capable of charging themselves in about a minute. The work appears in Nature1 this week.
Lithium-ion batteries are commonplace in everything from mobile phones to hybrid vehicles. "They're essentially devices that move lithium ions between electrodes," says Ceder. The batteries generate an electric current when lithium ions flow out from a storage electrode, float through an electrolyte, and are chemically bound inside the opposing cathode. To recharge the battery, the process is reversed: lithium ions are ripped from the cathode compound and sent back to be trapped in their anode store.
The speed at which a battery can charge is limited by how fast its electrons and ions can move - particularly through its electrodes. Researchers have boosted these rates by building electrodes from nanoparticle clumps, reshaping their surfaces, and using additives such as carbon. But for most lithium-ion batteries, powering up still takes hours: in part because the lithium ions, once generated, move sluggishly from the cathode material to the electrolyte.
That seemed to be the case for lithium iron phosphate (LiFePO4), a material that is used in the cathode of a small number of commercial batteries. But when Ceder and Kang did some calculations, they saw that the compound could theoretically do much better. Its crystal structure creates "perfectly sized tunnels for lithium to move through", says Ceder. "We saw that we could reach ridiculously fast charging rates."
So why hadn't anyone seen this speedy charging in practice? Ceder and Kang theorize that the lithium ions were having trouble finding their way to the crystal structure's express tunnels. The authors helped the ions by coating the surface of the cathode with a thin layer of lithium phosphate glass, which is known to be an excellent lithium conductor. Testing their newly-coated cathode, they found that they could charge and discharge it in as little as 9 seconds.
"As far as I know, this is the fastest yet for this material," comments Peter Bruce, a chemist at the University of St Andrews, UK. The researchers do not know exactly how the disordered glass helps lithium ions transfer between the electrolyte and the cathode.
Other materials, such as nickel oxide, have achieved similarly fast charging rates, says John Owen, a chemist at the University of Southampton, UK. "This is a nice demonstration of the concept in a lithium system," he says. Lithium, though, can store more energy for less weight than nickel compounds, and holds its charge better.
It's particularly important because lithium iron phosphate is already being used commercially, adds Bruce. Speeding lithium ion movement would vastly improve energy recovery in hybrid vehicles, which recharge their batteries when the vehicle brakes — a process that lasts only seconds. It could also eventually lead to fully electric vehicles that could charge reasonably quickly.
Ceder says that he thinks that improvements in modelling will allow researchers to find other candidates for ultra-fast batteries. "My guess is that there are more materials like this out there," he says.
Does it heat up and explode into flames?
W#OW!!!!!!!!!!!!!!!
“Does it heat up and explode into flames?”
Details, details.
now a hybrid or fully electric car is almost practical. Instead of an overnight charge you can actually charge up in the time it would take to fill up at a regualr gas station.
I’ve heard that the lithium batteries of the coming $40K Chevy Volt have to be replaces at 100,000 miles at the cost of $10K. Credibility?
Gotta have lots of amps to do it quick. That means big wires and big connections, big breakers. You don’t want to be fooling around with High Voltage charging your car.
If you don't mind the lights dimming!
You know what they say, don’t count your chickens before they are hatched.
Good question, one might think that that the speed at which it can be charged is also the speed that it can be discharged.
Only when it has to deal with leftwing idiots. The Senate needs them badly.
Sure.
If you discharge a large fully-charged battery in 9 seconds...
Solution: don't sell it to idiots.
Hmmm. How do they charge themselves? Sounds like free energy.
I've heard that the Prius needs battery replacement at 100,000 miles at a cost of $10,000.
You figure it out.
Interesting development. Quick recharges make as easy as filling up a gas tank. How much to chrage up the batterings?
How long do these batteries last? Cost to replace? Surely, as they become more commong/mass-produced, the cost of the batteries will go down.
Would like to see this combined with the new “aircars”. Compressed air, combined with batteries-gas engine-air recharger....best of all three worlds: Multiple power sources with air compression.
Solution: don't sell it to idiots.
Shorting it by accident would take an idiot.
On purpose? Just good fun.
Another benefit of the fast recharge rate is that I don’t have to “hook it up” at home, but simply go to a charging station.
But it’s not a viable product until Billy Mays does an infomercial selling it.
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