Electronics

New Li-ion anode achieves 70 percent charge in just two minutes

New Li-ion anode achieves 70 p...
A proof of concept nanotube-based anode for lithium-ion batteries has been developed by researchers at the Nanyang Technological University (Photo: NTU)
A proof of concept nanotube-based anode for lithium-ion batteries has been developed by researchers at the Nanyang Technological University (Photo: NTU)
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The long TiO2 nanotubes were manufactured with a simple mixing and stirring process (bottom row), vastly improving the length of the structure compared to previous methods (above) (Image: NTU)
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The long TiO2 nanotubes were manufactured with a simple mixing and stirring process (bottom row), vastly improving the length of the structure compared to previous methods (above) (Image: NTU)
The battery can charge at a very high rate of 25C for 10,000 cycles, compared to the typical 0.8C rate and 1,000 cycles for standard li-ion batteries (Image: NTU)
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The battery can charge at a very high rate of 25C for 10,000 cycles, compared to the typical 0.8C rate and 1,000 cycles for standard li-ion batteries (Image: NTU)
NTU Assoc Prof Xiaodong Chen with research fellow Tang Yuxin and PhD student Deng Jiyang (Photo: NTU)
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NTU Assoc Prof Xiaodong Chen with research fellow Tang Yuxin and PhD student Deng Jiyang (Photo: NTU)
NTU Assoc Prof Xiaodong Chen with research fellow Tang Yuxin and PhD student Deng Jiyang (Photo: NTU)
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NTU Assoc Prof Xiaodong Chen with research fellow Tang Yuxin and PhD student Deng Jiyang (Photo: NTU)
A proof of concept nanotube-based anode for lithium-ion batteries has been developed by researchers at the Nanyang Technological University (Photo: NTU)
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A proof of concept nanotube-based anode for lithium-ion batteries has been developed by researchers at the Nanyang Technological University (Photo: NTU)

Researchers at the Nanyang Technological University (NTU) in Singapore have developed a new, proof-of-concept anode for lithium-ion batteries that can charge to 70 percent of its capacity in only two minutes and has a very long lifespan of ten thousand charge/discharge cycles. The advance could lead to the production of high-rate lithium-ion batteries, with interesting implications for personal electronics and, perhaps, even electric vehicles.

Lithium-ion batteries owe their popularity to their ability to store large amounts of energy into a relatively small and light package; however, they can take a fairly long time to charge. This is largely due to the limitations of the battery anode, which is usually made of graphite. Namely, the lithium ions inside the battery need to travel a longer distance than strictly needed to reach the anode, taking more time than necessary. Secondly, the limited surface area of the electrode also slows down the rate at which the charging/discharging electrochemical reactions can take place.

A team of scientists led by Professor Xiaodong Chen has developed a proof-of-concept battery anode that addresses both these problems at the same time. The researchers replaced the standard graphite anode with a gel material containing long nanotubes made out of titanium dioxide, resulting in a much faster-charging battery which is also significantly more long-lived.

In a standard li-ion battery, the graphite electrode repeatedly expands and contracts, causing mechanical stresses that can lead to battery failure. By contrast, materials like titanium dioxide are very strong candidates for building long-lasting batteries because they don't significantly expand or contract during charge cycles.

The long TiO2 nanotubes were manufactured with a simple mixing and stirring process (bottom row), vastly improving the length of the structure compared to previous methods (above) (Image: NTU)
The long TiO2 nanotubes were manufactured with a simple mixing and stirring process (bottom row), vastly improving the length of the structure compared to previous methods (above) (Image: NTU)

Chen and colleagues were able to produce titanium dioxide nanotubes which were up to 40 micrometers in size – two orders of magnitude longer than previously achieved – by a simple process of mixing it with sodium hydroxide and stirring. Crucially, this made the nanostructures long enough to be useful for building a battery anode.

Shaping the material into intercalating nanotubes inside the anode allowed the researchers to greatly reduce the distance that lithium ions needed to travel in order to transfer their charge. Moreover, the nanotube structures also have a very large surface area of 130 square meters per gram (40,000 sq ft/oz), which significantly speeds up the chemical reactions that drive charging and discharging.

As a result, their proof-of-concept battery was able to reach 70 percent of its capacity in only two minutes at a current of 8.5 A (about four times greater than an iPad charger), though the researchers tell us it would take another hour for the battery to fully charge. The prototype was also tested for an impressive 10,000 charge/discharge cycles, which is about ten times more than current lithium-ions.

The battery can charge at a very high rate of 25C for 10,000 cycles, compared to the typical 0.8C rate and 1,000 cycles for standard li-ion batteries (Image: NTU)
The battery can charge at a very high rate of 25C for 10,000 cycles, compared to the typical 0.8C rate and 1,000 cycles for standard li-ion batteries (Image: NTU)

The technology is being licensed for mass-production, which Prof. Chen expects to take place within the next two years. The researchers tell us that scaling up the size of the battery is not an issue and will be done over the next year.

This development could potentially lead to much faster-charging and longer-lived batteries for our personal electronics. As far as the much larger batteries in electric cars, however, this pushes against the issue of supplying a high enough current to charge the battery that quickly (i.e., you'd need a very big cable, generate a lot of waste heat, and put a very strong stress on the electric grid).

A paper published in the journal Advanced Materials describes the advance.

Source: Nanyang Technological University

8 comments
MattII
Okay, this will really be a boost for electric cars.
mlmcasual
Please, Just stop.. Stop with all the "breakthrough" in Battery articles. Battery Breakthrough articles are the tech publication equivalent of penile enlargement popups. No.. we DON'T care about the 10,245th test tube claim at some university to give batteries 100x more capacity and charge rates. NOT ONE of those lab test tube claims has EVER amounted to anything.
Skipjack
Biggest problem for battery tech right now is not charging times, it is cost. Last time I checked titanium was A LOT more expensive than graphite.
Joel Detrow
mlmcasual, with most I'd agree with you, but this particular case is much more promising, and the key is that it's completely compatible with current manufacturing techniques, it's simply a matter of doing it. The materials involved are plentiful and easy to handle, and the researchers are already licensing it for mass production. For once, this is a development that we can actually expect. It's not claiming more capacity, just more robust charging. They found a loophole in producing the nanotubes - apparently it's literally as simple as mixing a few chemicals together, heating the mixture to a very specific temperature, and stirring. This isn't even a "test tube claim" at all. They produced an actual anode, which when combined with standard cathodes, created a battery with the stated advantages. People have been working to create a better anode for a LONG TIME, you shouldn't be so surprised that someone finally got it right. As for the concern raised by the article, this won't cause a strain on the grid at all, in my opinion. The ideal way to charge this quickly would be to have a capacitor bank store up slowly from the grid, and charge the car from that.
Stuart Wilshaw
Many of us are getting a bit fed-up with laboratory developments being hyped up as though they are going to be on sale tomorrow. Doing something in the lab; showing something as proof of concept isn't the same as developing a commercial product. This isn't a breakthrough it's just another way of protecting the anode from charging changes that damage it; there have been other ways demonstrated in the past and doubtless there will be many more in the future. And one day something will be developed that will end up being produced commercially, until then let's have less hype.
Intellcity
It seems many commentators forget this is a magazine about emerging technologies. The cutting edge often gets dull by the time all the cooking is done. Most scientific breakthroughs have been incremental improvements until that final tweak makes it economically feasible. And then actual production usually lags a few years behind the state of the art. If the authors were to wait until the process was proved and in production it wouldn’t be emerging tech any longer. You might be reading about it in the Wall Street Journal instead. But I would like to see more science and less hype.
Vishnu Bhan
These are all experimental prototypes and until it translates into a consumer grade product its all WIP. While such a battery would be great for electric cars, i don't see these being of any help to smaller consumer articles like mobile phones. To charge it, a current of 8.5A will need to flow into the device. To manufacture a phone and charger to handle such current would itself make it so bulky that it wont remain portable. Add to that safety issues........hence just like the saying "Electricity saved is electricity created"...... "Battery saved is battery charged"....:)
Slowburn
How fast will it discharge or what is the TNT equivalent of the ark.