In situ synthesis of lithium sulfide-carbon composites as cathode materials for rechargeable lithium batteries

Lithium-sulfur batteries are among the most promising candidates for next-generation rechargeable lithium batteries in view of recent progress on sulfur-carbon composite cathodes. However, further progress on such batteries is hampered by their concomitant need for a metallic lithium anode, which introduces new challenges associated with uneven electrodeposition and lithium dendrite formation. Here we report a method of creating lithium sulfide-carbon composites as cathode materials, which can be paired with high-capacity anodes other than metallic lithium. Lithium sulfide is dispersed in a porous carbon matrix, which serves to improve its electrical conductivity and provides a framework for sequestration of sulfur and lithium polysulfides. The in situ synthesis approach allows facile, scalable synthesis of lithium sulfide-carbon composite materials that exhibit improved electrochemical properties. We also investigate the effect of lithium polysulfides dissolved in the electrolyte on the stability and cycling behavior of Li2S-carbon composite cathodes.