Polysulfide immobilization and conversion on a conductive polar MoC@MoOx material for lithium-sulfur batteries

Lithium-sulfur batteries have attracted much attention because of their high theoretical energy density and cost effectiveness. However, severe polysulfide dissolution in organic electrolytes causes low sulfur utilization, fast capacity decay and poor coulombic efficiency. Here, we report a conductive polar MoC@MoOx material for efficient polysulfide immobilization and conversion during redox reactions. The polar MoOx shell enables the chemical adsorption of polysulfides, and the conductive MoC core facilitates the conversion of polysulfides to Li2S. The incorporation of the MoC@MoOx material in a carbon fiber foam electrode results in significantly improved electrochemical performance with a high specific capacity and good cycling stability. Our approach is a proof-of-concept study of the effective role of conductive polar materials in improving the redox chemistry of Li-S batteries.