Chemists have synthesized a new material that could show the way forward to state-of-the-art lithium-sulfur batteries for electric cars. 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 sulfur atoms, they are cheaper to make and less toxic than conventional lithium-ion power packs.
The chemists have produced 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 are important because they allow 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.