New li-ion battery anode could charge electronics in minutes

New li-ion battery anode could charge electronics in minutes
The new technology could allow lithium-ion batteries to charge 16 times faster than present models (Photo: Shutterstock)
The new technology could allow lithium-ion batteries to charge 16 times faster than present models (Photo: Shutterstock)
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Researchers Mihri and Cengiz Ozkan, both professors in the Bourns College of Engineering (Photo: UCR)
Researchers Mihri and Cengiz Ozkan, both professors in the Bourns College of Engineering (Photo: UCR)
Low-magnification and high-magnification SEM images of the cone-shaped carbon nanotube clusters (Image: UCR)
Low-magnification and high-magnification SEM images of the cone-shaped carbon nanotube clusters (Image: UCR)
The three-step process for producing the cone-shaped carbon nanotube clusters (Image: UCR)
The three-step process for producing the cone-shaped carbon nanotube clusters (Image: UCR)
The new technology could allow lithium-ion batteries to charge 16 times faster than present models (Photo: Shutterstock)
The new technology could allow lithium-ion batteries to charge 16 times faster than present models (Photo: Shutterstock)
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Researchers at the University of California, Riverside have developed a silicon anode that would allow us to charge lithium-ion batteries up to 16 times faster than is currently possible. The new design relies on a three-dimensional, cone-shaped cluster of carbon nanotubes that could also result in batteries that hold about 60 percent more charge while being 40 percent lighter.

Because lithium-ion batteries are ubiquitous in today's technology, a lot research is currently aimed at improving their performance, particularly by finding the "perfect" electrode materials. In commercial batteries, the anode is made out of graphitic carbon, which has a specific capacity of about 370 mAh/g (milliamp hours per gram). Anodes made out of carbon nanotubes could almost triple current performance, reaching up to around 1,000 mAh/g. However, researchers believe that switching away from carbon altogether would hold the greatest promise of all.

Silicon might be the ideal material for a Li-ion battery anode because it has a specific capacity of 4,200 mAh/g, which is over 10 times greater than commercial batteries. Replacing the anode in a standard Li-ion battery with a silicon one would lead to a cell with 63 percent higher capacity and 40 percent less weight. However, it's not easy to make a silicon anode work inside a Li-ion battery. As silicon interacts with lithium inside the cell, it repeatedly expands by up to 400 percent and then contracts to its original size. This leads to cracking and, eventually, a catastrophic failure of the battery.

Now, researchers at UCR have developed a new architecture for a silicon Li-ion battery anode that solves the cracking problem. This allows for the creation of a battery that is not only lighter and packing more energy, but which can also be charged much, much faster – up to 16 times faster, according to the researchers.

The three-step process for producing the cone-shaped carbon nanotube clusters (Image: UCR)
The three-step process for producing the cone-shaped carbon nanotube clusters (Image: UCR)

To build the anode, the scientists first took a graphene foil (which normally serves as the current collector for anodes in commercial batteries) and grew a nanostructure of pillared carbon nanotubes on top of it. They then applied a mild inductively coupled plasma, which turned the nanotubes into cone-shaped clusters. Lastly, amorphous silicon was deposited on top.

The researchers believe that the strong connection between the graphene-covered copper foil and the carbon nanotubes dramatically improves the contact between the active material and the current collector, which makes it possible to transfer both heat and charge much more quickly than usual. The cone-shaped nanopillars also allow the electrolyte to access the electrode faster, which further improves performance.

Lithium-ion batteries built using the new anode showed a great cycling stability even at very fast charge and discharge rates. The anodes achieved an impressive capacity of 1,954 mAh/g (over five times more than conventional anodes) and retained a capacity of 1,200 mAh/g, with charge being transferred with next to 100 percent efficiency after 230 charge and discharge cycles.

If such batteries can reach mass production, they might allow us to charge smartphones and electric cars in a matter of minutes rather than hours.

A paper published in the journal SMALL describes the advance.

Source: UCR

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Fretting Freddy the Ferret pressing the Fret
Sputtering amorphous silicon is a relatively simple thing to scale up. Plus, it can be integrated into a continuous process. I'm not familiar with the other techniques, however.
Paul Maher
Battery technology is taking off like a rocket. I have heard of 20 minute charge times for automotive applications and 30 second charge times for cell phones. I haven't been following battery technology as closely as I have been following energy production methods that have grown out of condensed matter physics, nanotechnology and the materials sciences. When quickly charged, high powered and inexpensive power generation gets hooked up with graphene/silicene/vanadium flow batteries BIG Oil and Nukes can bug off.
The Skud
Ha! Watch this fade away and disappear like many other battery advances seem to do when Big Oil notice the threat. Lighter cars with better power? These researchers will soon find their grant money drying up. Electric cars will not seriously take off until the 'charge v distance fear' is circumvented.
I fully agree with The Skud
week after week throughout the last 4/5 years we hear about breakthroughs i.e. Super-powered battery breakthrough claimed by US team - http://www.bbc.com/news/technology-22191650. Have any products reached the market?
The problem with conspiracy is that you require everyone to be more intelligent. Firstly you have these amazing discoveries by highly intelligent people and then you need another group of clever, resourceful people who never make mistakes to identify every possible challenge to their power base and cleverly suppress it.
People just aren't that clever and exaggerate how close they are to new discovery.
I know which one I go with.
@The Skud
I don't think the conspiracy theory holds much water. It requires a position that besting Li-Ion is somehow easy but big oil is running around covering up all the breakthroughs around the world. If you developed and owned a successor to Li-Ion that was both cheaper and better no amount of money could buy your silence because you would stand to gain trillions.
If you truly believe breakthroughs are easy to produce at scale but are just being covered up why not start your own battery company and get rich? By not doing this I can only conclude that even you probably don't believe your own conspiracy theory.
Another couple things worth mention is that Lithium batteries were discovered the in 1970s and are only just now reaching a point where price/performance makes them viable in things like automobiles. Just because research from 2013 isn't a commercially available product by 2014 doesn't mean it's a big oil conspiracy. The other important point is Lithium was first proposed for use in batteries by a guy who worked for none other than..... Exxon.
Marco McClean
Here's the difficulty I see with this claim and all similar claims:
60 times faster charge means 60 times the amperage at the power input (at the same voltage). For a phone that normally charges at 1A, that means a phone with the new miracle battery will draw 60 amps of current! That will require an 8-gauge Romex charging cable and a house-trailer-style power jack (the size of a vitamin bottle) inside the phone, and it will dim your (120V) house lights when you plug the charger into the wall-- unless you miniaturize a wall-voltage battery and heavy power supply for inside the phone. Which is only an engineering problem, not to mention making the phone an ongoing shock hazard, but it's a problem.
Electric vehicle batteries are already high voltage. Here, from Wikipedia: "Public EV charging stations provide 6 kW (host power of 208 to 240 VAC off a 40 amp circuit)." 60 times 40A is 240A. 60 times 6kW is 360,000 watts. If your charging station is meant for several cars, that will require its own power company transformer yard.
And the miracle solution to that is room-temperature superconductor wiring for grid, homes and devices. Which, you know, I guess-- maybe all this comes together at the Singularity.
@Marco McLean
I think you need to take Electricity 101. Do read the specs on the charger. Output of the charger is 5 VDC 1 amp , not the input. Even for hypothetical 100 % conversion efficiency it would boil down to 5 v/ 120 v x1 amp = 41 ma at the wall socket. Even with say 80 % conversion efficiency it would amount to no more than 50 ma at wall socket. Even for 60 times faster charging it would amount to no more than 3 A. For most of the world out side of north America it would be only half as much, 1.5 A only. Any house hold wiring can comfortably withstand it.
Yes, the problem you envisage would crop up on the output side. You would need cables the size of car jumper cables but at the same time the charger too would grow tremendously in size. Do you realize the kind of transistors required to be able to handle this current in switch mode? The numbers given are theoretical possibilities. I have a device with 3100 mah capacity Li-Polymer battery with a very strict restriction of 1.5 A maximum charging current.
BTW most phone chargers are more like 750 ma. I am quite sure this can be raised to something like 2000 - 2500 ma output capacity without increasing the size of the charger.
@Marco McClean I think the article said 16 times faster rather than 60 times faster but you still make a valid point. With EV I think 120 volt chargers use 15-20 amps, and 240 volt is about 30-40 amps. Quick charge stations are 480 volt and 80 amps and that's with todays charging times. So essentially people are generally already limited by the breakered amperage available in their homes for EV. Tesla will auto-adjust the amperage it pulls based on the plug you use and you can adjust it from the dash too (to prevent from throwing a breaker).
Looking at plugshare.com I think most people still use 120 volt chargers at home, going to 240 volt is mostly easy (a dryer or central air already uses 240v). Anything beyond that is going to be harder.
16x40A is actually 640 amps and my whole breaker box is only a 200 amp service so I wouldn't be able to do it at home but it's nothing that couldn't be done commercially. A Cisco CRS3 router takes 16 60A power feeds (for 960 breakered amps) and that's just one rack so powering 640 amp charge stations is still much easier than powering and cooling a data center.
Based on this post Tesla charging stations get a 12kV, 750kVA feed form the utility and step it down to 480v 200 amp feeds: http://www.teslamotors.com/forum/forums/updated-how-it-works-supercharger-station
They get 170 miles range per 30 minutes of charging with it.
@pmshah, If you are charging at 16 times the normal rate that does mean that you have either to raise the voltage or current if you keep the battery capacity constant. On the other hand if you keep the charging voltage/current constant you must reduce the capacity of the battery, simple Electricity 101 -you don't get something for nothing.
The other thing with fast charging is the problem of heat being generated by the reactions. If you can't get rid of that heat you end up with a fire on your hands as several people have found when they used a higher current charger than the one supplied with their phone.
For those saying there is a conspiracy by Big Oil to suppress this type of technology, you need to find out exactly who are providing the funds for much of this research and be prepared for a surprise - it is the same Big Oil you are so against. You will also find that what can be done in a research environment does not scale to being viable in the real world - a replacement phone battery for £/$ 5000 anyone? For these batteries and any others like them they have to be able to be manufactured and sold for a price that is very near to a standard battery of the same capacity. If that can't be done don't expect them to be seen in the market because people will not pay.
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