Holger Althues, coordinator of the IWS Battery Center and project manager of several related research projects presents the latest results of current research findings: “To my mind lithium-sulfur batteries are the most promising innovation for future energy storage devices.” They have two to four times more specific energy than conventional lithium-ion batteries. “A further advantage is that sulfur is an abundant, non-toxic and inexpensive material in contrast to cobalt-based cathode materials.

The major challenge, however, is to improve the lifespan of lithium-sulfur batteries. Novel materials, such as nano-structured carbon-sulfur composites, solid-state electrolytes and silicon-alloy anodes promise a drastic increase of stability. Recently, IWS scientists succeeded in developing lithium-sulfur cells, which demonstrate with their more than 1300 charge/discharge cycles an excellent efficiency of nearly 100 %. The significantly improved cell stability can be clearly attributed to the novel material composition. The IWS scientists combined carbon-silicon composite cathodes with porous carbon-sulfur cathodes. Due to high sulfur utilization these nano-composite cathodes allow for a specific capacity of more than 1400 Ah kg^-1 (related to the mass of sulfur).