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.