The facile synthesis and enhanced lithium-sulfur battery performance of an amorphous cobalt boride (Co₂B)@graphene composite cathode

Rechargeable lithium-sulfur (Li-S) batteries have attracted extensive attention as next-generation energy storage devices, owing to their high theoretical energy density, environmental benignancy, and cost effectiveness. However, the commercial application of Li-S batteries is limited because of the severe polysulfide shuttle effect, the insulating nature of sulfur, and fast capacity decay. To address these obstacles, we report for the first time a facile synthesis of an amorphous cobalt boride (Co₂B)@graphene material as a novel sulfur host, which provides high specific capacity and cycling performance. Endowed by the unique "synergistic effect" of Co and B interaction with polysulfides and the high electrical conductivity of graphene, the cobalt boride (Co₂B)@graphene composite shows a specific capacity of 1487 mA h g^-1 at 0.1C and delivers an outstanding cycling performance with a capacity of 758 mA h g^-1 for the 450^th cycle at 1C, representing a 0.029% fading rate per cycle.