Feeds

Hemp used to make graphene-like supercapacitors

Pass de battery on de left-hand-side

High performance access to file storage

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.” ®

High performance access to file storage

More from The Register

next story
Elon Musk's LEAKY THRUSTER gas stalls Space Station supply run
Helium seeps from Falcon 9 first stage, delays new legs for NASA robonaut
KILLER SPONGES menacing California coastline
Surfers are safe, crustaceans less so
LOHAN's Punch and Judy show relaunches Thursday
Weather looking good for second pop at test flights
Discovery time for 200m WONDER MATERIALS shaved from 4 MILLENNIA... to 4 years
Alloy, Alloy: Boffins in speed-classification breakthrough
Red-faced LOHAN team 'fesses up in blown SPEARS fuse fiasco
Standing in the corner, big pointy 'D' hats
Curiosity finds not-very-Australian-shaped rock on Mars
File under 'messianic pastries' and move on, people
Top Secret US payload launched into space successfully
Clandestine NRO spacecraft sets off on its unknown mission
Get your MOON GEAR: Auction to feature Space Race memorabilia
Keepsakes from early NASA, Soviet programs up for bids
New FEMTO-MOON sighted BIRTHING from Saturn's RING
Icy 'Peggy' looks to be leaving the outer rings
prev story

Whitepapers

Securing web applications made simple and scalable
In this whitepaper learn how automated security testing can provide a simple and scalable way to protect your web applications.
Five 3D headsets to be won!
We were so impressed by the Durovis Dive headset we’ve asked the company to give some away to Reg readers.
HP ArcSight ESM solution helps Finansbank
Based on their experience using HP ArcSight Enterprise Security Manager for IT security operations, Finansbank moved to HP ArcSight ESM for fraud management.
The benefits of software based PBX
Why you should break free from your proprietary PBX and how to leverage your existing server hardware.
Mobile application security study
Download this report to see the alarming realities regarding the sheer number of applications vulnerable to attack, as well as the most common and easily addressable vulnerability errors.