Feeds

Boffins build 'intimate contact' cathode for e-car 'super' batteries

Lithium-sulphur tech a step closer to commercialisation?

SANS - Survey on application security programs

Scientists from Canada's University of Waterloo have developed what they claim is a crucial step forward in the creation of lithium-sulphur rechargeable batteries.

A team led by Professor Linda Nazar have created a cathode capable of sustaining a reversible electrochemical reaction at high current rates.

Lithium-sulphur is seen as a strong contender for the next generation of rechargeable batteries thanks to an energy density way higher than lithium-ion. The upshot: batteries can be made smaller and still support a higher capacity than li-ion equivalents. They're also made from cheaper and less toxic materials.

The car industry is keen on the technology, hoping it with dramatically extend the range of plug-in e-cars. Not to mention the fact, that lithium-sulphur batteries are less, how shall we say, volatile than li-ions, as some notebook owners have found to their cost.

Li-S batteries have an energy density of around 2600Wh/kg. That's more than ten times the 250Wh/kg density of today's Li-ion e-car batteries.

There are problems with the technology, however. Lithium-sulphur designs currently support far fewer recharge cycles than Li-ion. Nazar's contribution helps out with another issue: getting the cathode-end reaction to store and release efficiently during the charge-recharge operations.

Lithium-sulphur battery cathode designs have, to date, been made using a variety of carbon-sulphur materials, none of which has brought the two substances close enough together to ensure smooth electron flow.

Nazar's approach used a form of carbon called 'mesporous carbon' to create an array of 6.5nm-thick carbon rods, each 3-4nm apart. The rods contain tiny pores of a consistent depth and diameter.

Liquid sulphur was poured onto the array and drawn onto the rods' pores by capillary action. The result, Nazar said, was a "most intimate" contact between the electrically active sulphur and the carbon cathode - essentially a much bigger surface area for electron exchange than has been achieved before.

"This composite material can supply up to nearly 80 per cent of the theoretical capacity of sulphur, which is three times the energy density of lithium transition metal oxide cathodes, at reasonable rates with good cycling stability," claimed Nazar.

The next step: refine the process to improve its charge-recharge performance before commercialising the technique. ®

3 Big data security analytics techniques

More from The Register

next story
Most Americans doubt Big Bang, not too sure about evolution, climate change – survey
Science no match for religion, politics, business interests
KILLER SPONGES menacing California coastline
Surfers are safe, crustaceans less so
Discovery time for 200m WONDER MATERIALS shaved from 4 MILLENNIA... to 4 years
Alloy, Alloy: Boffins in speed-classification breakthrough
LOHAN and the amazing technicolor spaceplane
Our Vulture 2 livery is wrapped, and it's les noix du mutt
Liftoff! SpaceX Falcon 9 lifts Dragon on third resupply mission to ISS
SpaceX snaps smartly into one-second launch window
Opportunity selfie: Martian winds have given the spunky ol' rover a spring cleaning
Power levels up 70 per cent as the rover keeps on truckin'
Elon Musk's LEAKY THRUSTER gas stalls Space Station supply run
Helium seeps from Falcon 9 first stage, delays new legs for NASA robonaut
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.
Combat fraud and increase customer satisfaction
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.
SANS - Survey on application security programs
In this whitepaper learn about the state of application security programs and practices of 488 surveyed respondents, and discover how mature and effective these programs are.
3 Big data security analytics techniques
Applying these Big Data security analytics techniques can help you make your business safer by detecting attacks early, before significant damage is done.