Feeds

Hemp used to make graphene-like supercapacitors

Pass de battery on de left-hand-side

Internet Security Threat Report 2014

A group of scientists from the University of Alberta have created a process that makes graphene-like nanomaterials out of hemp waste, suitable for use in supercapacitors.

While graphene is already known to be a good energy store, it's also expensive, so commercial supercapacitors use activated carbon electrodes.

According to a paper published by the American Chemical Society, the material created by the University of Alberta group has a power density of up to 49 kWatt-hours per kilo (depending on temperature), capacitance up to 142 Farads per gram, and able to support current density of 100 amps per gram.

According to University of Alberta chemical engineer David Mitlin, hemp bast – a waste product in industrial hemp production – is suitable for processing into nanosheets. He told the ACS publication Chemical and Engineering News that bast is “a nanocomposite made up of layers of lignin, hemicellulose, and crystalline cellulose. If you process it the right way, it separates into nanosheets similar to graphene.”

The processing involves heating the bast to break down the lignin and hemicellulose, and to carbonise the crystalline cellulose. The resulting material is treated with potassium hydroxide, heated to between 700 and 800°C, at which point it exfoliates into sheets with pores between 2nm and 5nm in diameter. The pores provide the path for quick charging and discharging, when the hemp-waste electrodes are assembled with an ionic electrolyte.

The group says the 12 Wh per kilo density of the assembled supercapacitor is “higher than that of commercially available supercapacitors.” ®

Internet Security Threat Report 2014

More from The Register

next story
FORGET the CLIMATE: FATTIES are a MUCH BIGGER problem - study
Fat guy? Drink or smoke? You're worse than a TERRORIST
Renewable energy 'simply WON'T WORK': Top Google engineers
Windmills, solar, tidal - all a 'false hope', say Stanford PhDs
Rosetta probot drilling DENIED: Philae has its 'LEG in the AIR'
NOT best position for scientific fulfillment
SEX BEAST SEALS may be egging each other on to ATTACK PENGUINS
Boffin: 'I think the behaviour is increasing in frequency'
HUMAN DNA 'will be FOUND ON MOON' – rocking boffin Brian Cox
Crowdfund plan to stimulate Blighty's space programme
Post-pub nosh neckfiller: The MIGHTY Scotch egg
Off to the boozer? This delicacy might help mitigate the effects
I'M SO SORRY, sobs Rosetta Brit boffin in 'sexist' sexy shirt storm
'He is just being himself' says proud mum of larger-than-life physicist
NASA launches new climate model at SC14
75 days of supercomputing later ...
LIFE, JIM? Comet probot lander found 'ORGANICS' on far-off iceball
That's it for God, then – if Comet 67P has got complex molecules
prev story

Whitepapers

Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
A strategic approach to identity relationship management
ForgeRock commissioned Forrester to evaluate companies’ IAM practices and requirements when it comes to customer-facing scenarios versus employee-facing ones.
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?
Protecting against web application threats using SSL
SSL encryption can protect server‐to‐server communications, client devices, cloud resources, and other endpoints in order to help prevent the risk of data loss and losing customer trust.
Top 5 reasons to deploy VMware with Tegile
Data demand and the rise of virtualization is challenging IT teams to deliver storage performance, scalability and capacity that can keep up, while maximizing efficiency.