Mar 7 2017
Bingqing Wei and colleagues are working to build a better lithium-sulfur battery. (Credit - Kathy F. Atkinson/University of Delaware)
Most of today’s portable electronics including cell phones, laptops, tablets, smart watches, and fitness trackers are powered by rechargeable lithium-ion (Li-ion) batteries. However, their energy density - the quantity of energy stored within a given quantity of physical space, or mass - will have to be enhanced for these batteries to be extensively used in electric transport and smart grid applications.
In contrast, lithium-sulfur (Li-S) batteries possess five times more energy density than Li-ion batteries. This energy advantage combined with the low cost suggests that this alternative technology holds potential for high-energy storage applications.
But the utilization of Li-S batteries is restricted by a different issue: rapid capacity fade, meaning that the quantity of charge these batteries can deliver at the rated voltage reduces greatly with use.
Bingqing Wei, professor in the Department of Mechanical Engineering at the University of Delaware, explains that this issue stems from a phenomenon known as the polysulfide shuttle effect, where the spontaneous development of polysulfides hinders performance.
Now, Wei and colleagues have shown a new polysulfide entrapping strategy that significantly enhances the cycle stability of Li-S batteries.
The research details can be found in the scientific article “Ferroelectric-Enhanced Polysulfide Trapping for Lithium-Sulfur Battery Improvement” published recently in Advanced Materials. The authors include researchers from Northwestern Polytechnical University, Shenzhen University and Hong Kong Polytechnic University in China.
Wei explains that the incorporation of ferroelectric nanoparticles into the battery cathode anchors the polysulfides, stopping them from dissolving and resulting in the loss of active materials at the cathode.
While the mechanism underlying the trapping of polysulfides is unclear at this point, we’re optimistic about the potential of this approach to high-performance lithium-sulfur battery applications, as it not only solves the problem of the polysulfide shuttle effect but also can be seamlessly coupled to current industrial battery manufacturing processes.
Bingqing Wei, Professor, University of Delaware