Feeds

Get BENT: Flexy supercapacitor breaks records

Carbon nanofibre comparable with lithium batteries

5 things you didn’t know about cloud backup

It doesn't sound like a huge number, but 6.3 milliwatt-hours per cubic mm is a breakthrough: it's the highest volumetric energy density so far achieved in a microscale carbon-based supercapacitor.

Such devices are keenly sought in electronics research to drive the growing wearables market, since battery life is a big issue among glassholes and fitness-tracker owners alike. The right supercaps would be a boon, offering decent battery life and faster charging than the ubiquitous Li-ion battery.

In a paper at Nature Nanotechnology (abstract here), researchers from Nanyang Technological University (NTU) in Singapore, Tsinghua University in China, and Case Western Reserve University in the United States describe their supercapacitor as: “a hierarchically structured carbon microfibre made of an interconnected network of aligned single-walled carbon nanotubes with interposed nitrogen-doped reduced graphene oxide sheets.”

Apart from energy density, what's really excited the group is that they've created a scalable process to produce their materials. They say they've produced their carbon microfibres in 50 metre lengths, and see no serious limit to scalability.

The challenge for supercapacitors is that you need to offer a large surface area for carrying charges. A conventional capacitor is a simple creature indeed: charge-carrying foil plates, separated by a dielectric. That kind of cap' can deliver high current, but only for a short time – to store more charge, a supercapacitor has to squeeze a much higher surface area in a similar volume, while still keeping the positive and negative plates separated.

The group, led by NTU professor Yuan Chen, created a setup in which a solution containing single-wall nanotubes, graphene oxide, and ethylenediamine is pumped through a capillary column and heated in an oven for six hours.

The process causes sheets of graphene and carbon nanotubes to self-assemble into a network that runs along the length of the fibre. The resulting material, essentially a long fibrous capacitor, presents 396m2 of surface area per gram of fibre, giving the material its high capacity.

It can also be woven, which opens up applications like “smart clothing” or, more prosaically, to power medical devices, and the group claims good performance over 10,000 charge cycles.

The group says the 6.3 milliwatt-hour per cubic mm result is comparable to a 4V, 500 micro-amp-hour lithium thin film battery. ®

Boost IT visibility and business value

More from The Register

next story
China building SUPERSONIC SUBMARINE that travels in a BUBBLE
Shanghai to San Fran in two hours would be a trick, though
Our LOHAN spaceplane ballocket Kickstarter climbs through £8000
Through 25 per cent but more is needed: Get your UNIQUE rewards!
Cutting cancer rates: Data, models and a happy ending?
How surgery might be making cancer prognoses worse
Boffins ID freakish spine-smothered prehistoric critter: The CLAW gave it away
Bizarre-looking creature actually related to velvet worms
CRR-CRRRK, beep, beep: Mars space truck backs out of slippery sand trap
Curiosity finds new drilling target after course correction
SpaceX prototype rocket EXPLODES over Texas. 'Tricky' biz, says Elon Musk
No injuries or near injuries. Flight stayed in designated area
Brit balloon bod Bodnar overflies North Pole
B-64 amateur ultralight payload approaching second circumnavigation
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Endpoint data privacy in the cloud is easier than you think
Innovations in encryption and storage resolve issues of data privacy and key requirements for companies to look for in a solution.
Scale data protection with your virtual environment
To scale at the rate of virtualization growth, data protection solutions need to adopt new capabilities and simplify current features.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?