Skip to comments.Batteries charge quickly and retain capacity, thanks to new structure
Posted on 03/20/2011 1:37:56 PM PDT by decimon
CHAMPAIGN, Ill. The batteries in Illinois professor Paul Braun's lab look like any others, but they pack a surprise inside.
Braun's group developed a three-dimensional nanostructure for battery cathodes that allows for dramatically faster charging and discharging without sacrificing energy storage capacity. The researchers' findings will be published in the March 20 advance online edition of the journal Nature Nanotechnology.
Aside from quick-charge consumer electronics, batteries that can store a lot of energy, release it fast and recharge quickly are desirable for electric vehicles, medical devices, lasers and military applications.
"This system that we have gives you capacitor-like power with battery-like energy," said Braun, a professor of materials science and engineering. "Most capacitors store very little energy. They can release it very fast, but they can't hold much. Most batteries store a reasonably large amount of energy, but they can't provide or receive energy rapidly. This does both."
The performance of typical lithium-ion (Li-ion) or nickel metal hydride (NiMH) rechargeable batteries degrades significantly when they are rapidly charged or discharged. Making the active material in the battery a thin film allows for very fast charging and discharging, but reduces the capacity to nearly zero because the active material lacks volume to store energy.
Braun's group wraps a thin film into three-dimensional structure, achieving both high active volume (high capacity) and large current. They have demonstrated battery electrodes that can charge or discharge in a few seconds, 10 to 100 times faster than equivalent bulk electrodes, yet can perform normally in existing devices.
This kind of performance could lead to phones that charge in seconds or laptops that charge in minutes, as well as high-power lasers and defibrillators that don't need time to power up before or between pulses.
Braun is particularly optimistic for the batteries' potential in electric vehicles. Battery life and recharging time are major limitations of electric vehicles. Long-distance road trips can be their own form of start-and-stop driving if the battery only lasts for 100 miles and then requires an hour to recharge.
"If you had the ability to charge rapidly, instead of taking hours to charge the vehicle you could potentially have vehicles that would charge in similar times as needed to refuel a car with gasoline," Braun said. "If you had five-minute charge capability, you would think of this the same way you do an internal combustion engine. You would just pull up to a charging station and fill up."
All of the processes the group used are also used at large scales in industry so the technique could be scaled up for manufacturing.
They key to the group's novel 3-D structure is self-assembly. They begin by coating a surface with tiny spheres, packing them tightly together to form a lattice. Trying to create such a uniform lattice by other means is time-consuming and impractical, but the inexpensive spheres settle into place automatically.
Then the researchers fill the space between and around the spheres with metal. The spheres are melted or dissolved, leaving a porous 3-D metal scaffolding, like a sponge. Next, a process called electropolishing uniformly etches away the surface of the scaffold to enlarge the pores and make an open framework. Finally, the researchers coat the frame with a thin film of the active material.
The result is a bicontinuous electrode structure with small interconnects, so the lithium ions can move rapidly; a thin-film active material, so the diffusion kinetics are rapid; and a metal framework with good electrical conductivity.
The group demonstrated both NiMH and Li-ion batteries, but the structure is general, so any battery material that can be deposited on the metal frame could be used.
"We like that it's very universal, so if someone comes up with a better battery chemistry, this concept applies," said Braun, who is also affiliated with the Materials Research Laboratory and the Beckman Institute for Advanced Science and Technology at Illinois. "This is not linked to one very specific kind of battery, but rather it's a new paradigm in thinking about a battery in three dimensions for enhancing properties."
The U.S. Army Research Laboratory and the Department of Energy supported this work. Visiting scholar Huigang Zhang and former graduate student Xindi Yu were co-authors of the paper.
Editor's note: To reach Paul V. Braun, call 217-244-7293; e-mail firstname.lastname@example.org.
could this give a jolt to the dolt’s Volt?
Probably not. Volt's biggest downside isn't the time it takes to charge the batteries, but the utility that the vehicle gets out of the charge itself. It needs batteries that can store MUCH more potential energy than batteries are capable of storing today, irrespective of charging time.
At least that's the way the absolute NON-ENGINEER sees it.
Zinc was the last medicine show through town, yeah they're great (higher voltage, every new tech trumpets some "new' gimmick), but how are they workin' out for you now?
Btw- whose recycling these crap piles?
I'm sure most just toss in nearest trash can whose contents goes to landfill or trash to electricity burn plant.
Would make them fine for cities though.
Expect there to be ramped up efforts to tax car use other ways than at the pump. This thing will become viable relatively soon.
There is NO way they are taxing based on miles driven though, with tracking. It should be a flat road tax for each car, with a simultaneous reduction in gas tax.
Well, a lot of battery issues are fragility (obviously, not good in a car, never mind accidents, vibrations), self-discharge, cycling, cold-weather performance, and rate of charge.
The downside of being able to charge quickly, is...with what kind of current? It wouldn’t be that useful for a car to be able to charge in five minutes if the charger had to be next to an industrial substation. Also, generally, batteries that charge quickly...also discharge internally quickly (that is, whether they are used or not). This MIGHT be OK in a car, or a portable device/weapon such as a laser or rail gun.
It’s really difficult to get ALL the good qualities you want at once.
Actually, he did substantial quality control testing using his wife’s vibrator. She has a very big smile!
Somehow I don’t buy this.
Will be available the same week that algea fuels start pumping into shock wave disc energy equipped cars.
Put batteries like that in my IPhone and I will be a very happy man indeed.
How soon can we get them?Not soon enough.
If it can lead to quick charges, then even in cold climates that would be useful.
Even if the Volt’s range is only 150 km in cold weather, if it means that I’d only have to plug it in once a day for a half hour, it wouldn’t be that inconvenient.
But yeah, storage capacity is where it’s at.
wow...makes a person appreciate the energy density of a gallon of gasoline even more...
Which brings to mind my question...well, one of them...about electric vehicles. How will a battery powered vehicle fare in Northern climes during the winter? Anyone who has experienced a New England or Minnesota Winter will know how batteries perform in low temperatures.
Does one need to keep the danged thing pugged in all night? That brings up another question about who will be paying for the infrastructure upgrades to the electrical grid if electric cars catch on? Imagine all the people in one area of homes having electric cars. Current infrastructure will not handle the extra load. No way.
I was reading one of the auto mag's reports on a Volt that was tested in the CT area during the winter, and the performance was absolutely abyssal and WAY BELOW what the range was that was claimed by GM - around 40 miles was what the cold-weather testers got. I think it was Consumer Reports, but am not positive.
"Does one need to keep the danged thing pugged in all night?"
Yes, I believe it's an overnight (5 or so hours) charge.
"Imagine all the people in one area of homes having electric cars. Current infrastructure will not handle the extra load. No way."
That very well may be true. I don't have any useful knowledge of the residential power grid, so I don't know what the practical impact would be of wide-spread use of these kinds of things.
I think (but am not positive) that the charger is not a standard 110 wall outlet, but requires the same kind of plug that many electric dryers need. Maybe somebody else can comment???
Nobody does infrastructure analysis anymore. Problem with digital age engineers/technologists is they tend to forget industrial age issues such as logistics and infrastructure. Li ion cars must wait 10 or more years in order to develop the mines to provide lithium metals for battery factories. Current production can provide batteries for only 40 to 60,000 vehicles a year. I had a electric car supporter point out reports showing there is enough lithium ore in the ground to support 20 to 40 million vehicles a year, but most of it is still in the ground awaiting for mines to be built (can take 10 years to set up after legal challenges and etc). So can GM afford to build a car line that sells only 40 to 60,000 vehicles a year for ten years.
Next issue is as we attempt to recharge the batteries quicker, the DC power source to do the charging must get many factors larger. Example if it takes 10 hours to recharge a 1000 kWH battery, you will need 100 watt DC source. If you want to recharge the same battery in one hour, you will need a 1000 watt DC source. If you want to recharge the battery in five minutes you will need a 12000 watt DC source. If a recharge station has 8 stations it will need 96 000 watt DC power. DC burns hot and the cable providing the power will be immense. God help you if you accidentally touched the wrong terminal during charging, try human toast. The power and size of power cables/lines would be immense. By the way 5000 watt generator can provide power for a military forward operating base.
"This system that we have gives you capacitor-like power with battery-like energy," said Braun, a professor of materials science and engineering. "Most capacitors store very little energy. They can release it very fast, but they can't hold much. Most batteries store a reasonably large amount of energy, but they can't provide or receive energy rapidly. This does both."Power is the rate of energy use, common electric power units are watts and kilowatts.
Energy is how much power is used or available to be used, the common electric energy units is kilowatt-hours.
The batteries in these things are about 20 kw hours, meaning if you were to charge them in 5 minutes minutes you would be loading the grid with 240KW which would be over 1000 amps at 220V.
Good luck with that! Most houses in the United States have 60 or 100 amp service.
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