Jul
1
Improving the Electric Vehicle Battery
July 1, 2014 | Leave a Comment
An electric vehicle (EV) mass market depends on a much better battery. Researchers in Germany and Canada have now synthesized a new material that could make progress in the way forward to state-of-the-art lithium-sulfur batteries.
Much of the EV industry is putting most of its hope in lithium-sulfur batteries, which have a very high storage capacity. Plus, thanks to the inclusion of sulfur atoms, the lithium -sulfur batteries are cheaper to make and less toxic than conventional lithium-ion power packs.
But the lithium-sulfur technology still presents several major challenges that need to be resolved until it can be integrated into cars. Most troubling is both the rate and the number of possible charge-discharge cycles needs to be increased before the lithium-sulfur battery can become a realistic alternative to lithium-ion batteries.
Chemists Professor Thomas Bein at Ludwig-Maximilians-Universitaet (LMU), Coordinator of the Energy Conversion Division of the Nanosystems Initiative Munich and Professor Linda Nazar at the University of Waterloo, Waterloo Institute of Nanotechology Ontario, Canada with 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. The research paper has been published in the journal Chemistry of Materials.
The press release said 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.
Lithium Sulfur Battery Carbon Nanotubes. Click image for more info.
Benjamin Mandlmeier, a postdoc in Bein’s Institute and a first co-author on the new study, explained, “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.”
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 prepared 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.
Professor Bein said, “Nanostructured materials have great potential for the efficient conversion and storage of electrical energy. 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.”
Battery chemistries have been getting a lot of attention with element blends being seen more and more. There looks to be a few good prospects coming along nicely. What will really make the future, is the first one to survive or better still, bloom under the crucible of scaling up to mass market manufacturing.
Comments
Feedburner
Reddit
Stumbleupon
