Chemists seek state-of-the-art lithium-sulfur batteries

July 1, 2014
Chemists seek state-of-the-art lithium-sulfur batteries

When can we expect to drive the length of Germany in an electric car without having to top up the battery? Chemists at the NIM Cluster at LMU and at the University of Waterloo in Ontario, Canada, have now synthesized a new material that could show the way forward to state-of-the-art lithium-sulfur batteries.

Whether or not the future of automotive traffic belongs to the softly purring electric car depends largely on the development of its batteries. The industry is currently placing most of its hopes in lithium-sulfur batteries, which have a very high storage capacity. Moreover, thanks to the inclusion of , they are cheaper to make and less toxic than conventional lithium-ion power packs.

However, the lithium-sulfur battery still presents several major challenges that need to be resolved until it can be integrated into cars. For example, both the rate and the number of possible charge-discharge cycles need to be increased before the can become a realistic alternative to lithium-ion batteries.

Lots of pores for sulfur

The chemists Professor Thomas Bein (LMU), Coordinator of the Energy Conversion Division of the Nanosystems Initiative Munich, Professor Linda Nazar (University of Waterloo, Waterloo Institute of Nanotechology) and their colleagues have now succeeded in producing a novel type of nanofiber, whose highly ordered and porous structure gives it an extraordinarily high surface-to-volume ratio. Thus, a sample of the new material the size of a sugar cube presents a surface area equivalent to that of more than seven tennis courts.

"The high surface-to-volume ratio, and high pore volume is important because it allows sulfur to bind to the electrode in a finely divided manner, with relatively high loading. Together with its easy accessibility, this enhances the efficiency of the electrochemical processes that occur in the course of charge-discharge cycles. And the rates of the key reactions at the sulfur electrode-electrolyte interface, which involve both electrons and ions, are highly dependent on the total surface area available," as Benjamin Mandlmeier, a postdoc in Bein's Institute and a first co-author on the new study, explains.

The secret recipe

A novel recipe and a cleverly designed mode of synthesis are the key factors that determine the properties of the new materials. To synthesize the carbon fibers, the chemists first prepare a porous, tubular silica template, starting from commercially available, but non-porous fibers. This template is then filled with a special mixture of carbon, silicon dioxide and surfactants, which is then heated at 900°C. Finally the template and the SiO2 are removed by an etching process. During the procedure, the carbon nanotubes – and thus the pore size – shrink to a lesser extent than they would in the absence of the confining template, and the fibers themselves are correspondingly more stable.

"Nanostructured materials have great potential for the efficient conversion and storage of electrical energy," says Thomas Bein. "We in the NIM Cluster will continue to collaborate closely with our colleagues in the Bavarian SolTech Network in order to explore and exploit the properties of such structures and their practical applications."

Explore further: Sulfur in every pore: Improved batteries with carbon nanoparticles

More information: "Bimodal Mesoporous Carbon Nanofibers with High Porosity: Freestanding and Embedded in Membranes for Lithium–Sulfur Batteries." Guang He, Benjamin Mandlmeier, Jörg Schuster, Linda F. Nazar, and Thomas Bein. Chemistry of Materials Article ASAP. DOI: 10.1021/cm403740r

Related Stories

Battery development may extend range of electric cars

January 9, 2014

It's known that electric vehicles could travel longer distances before needing to charge and more renewable energy could be saved for a rainy day if lithium-sulfur batteries can just overcome a few technical hurdles. Now, ...

The ultra-high volumetric energy density lithium-sulfur battery

January 23, 2014

Lithium ion battery technology (LIBs) is one of the most important mobile power sources for laptops, cameras, and smart phones. However, the current energy density of LIBs is approaching the theoretical limit, which underscoring ...

Lithium sulfur: A battery revolution on the cheap?

June 4, 2014

(Phys.org) —Whip together an industrial waste product and a bit of plastic and you might have the recipe for the next revolution in battery technology. Scientists from the National Institute of Standards and Technology ...

Recommended for you

New nanomaterial maintains conductivity in 3-D

September 4, 2015

An international team of scientists has developed what may be the first one-step process for making seamless carbon-based nanomaterials that possess superior thermal, electrical and mechanical properties in three dimensions.

Making nanowires from protein and DNA

September 3, 2015

The ability to custom design biological materials such as protein and DNA opens up technological possibilities that were unimaginable just a few decades ago. For example, synthetic structures made of DNA could one day be ...

Graphene made superconductive by doping with lithium atoms

September 2, 2015

(Phys.org)—A team of researchers from Germany and Canada has found a way to make graphene superconductive—by doping it with lithium atoms. In their paper they have uploaded to the preprint server arXiv, the team describes ...

For 2-D boron, it's all about that base

September 2, 2015

Rice University scientists have theoretically determined that the properties of atom-thick sheets of boron depend on where those atoms land.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

betterexists
1 / 5 (5) Jul 01, 2014
What Prevented Cars from being Coated with Plastic Solar Panels? Drivers could sell their Charged Batteries at Gas Stations and Someone else in need might put them to use!
No need to stand at the counters for credit; Just Make the process of dumping the charged battery & being credited an Automatic Process.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.