Rechargable lithium-sulfur (Li-S) batteries have a large potential, with a theoretical energy density five times higher than lithium-ion batteries, which are dominating the market today. Li-S batteries also uses less expensive and more abundant materials. However, there are some challenges that need to be resolved before Li-S batteries will be implemented in a large industrial scale. Among the most important is that sulfur from the cathode can migrate through the battery and be lost and that lithium dendrite structures can form on the anode. Both of these mechanisms deteriorates the performance and lifetime of Li-S batteries. Advanced, tailored separators can contribute to solving these challenges and realize the potential of Li-S batteries.
A separator is a thin, porous layer between the anode and the cathode in a battery. Its purpose is to prevent electrical short circuit while at the same time enabling ions to pass from side to side when the battery is cycled. For Li-S batteries it is vital that Li+-ions can pass, but that intermediate reaction products where lithium is chemically bound to sulfur (so-called lithium polysulfides, Li2Sx) are prevented from leaving the cathode and give capacity loss. The goal of the 3S Battery project (Super Selective Separators for Battery applications) is to develop highly effective separators with tailored functionalities using advanced nanostructures and/or coatings to mitigate the problems caused by polysulfide migration and dendrite formation.
3S Battery is a technology convergence researcher project financed by the Research Council of Norway. The project is coordinated by NTNU with SINTEF and University of Uppsala as partners and is an interdisciplinary collaboration between experts within nanomaterials, membranes and batteries.