Achieving job-synergistic polysulfides adsorption-conversion within hollow structured MoS/CoS/C heterojunction host for long-life lithium-sulfur batteries.

Lithium-sulfur batteries are considered one of the most promising next-generation energy storage devices owing to their ultrahigh theoretical energy density and environmental friendliness. However, the sluggish electrode reaction kinetics of the sulfur cathode and shuttle effects of lithium polysulfide (LiPSs) restrict their active material utilization and cycling stability. Herein, a hollow, free-standing MoS/CoS/C heterojunction was fabricated and employed as a cathode host for high-performance lithium-sulfur batteries (LSBs). The unique hollow nanostructured MoS/CoS/C can achieve job-synergistic polysulfide adsorption-conversion, in which the conductive nitrogen-doped carbon framework facilitates rapid electron/ion diffusion; polar CoS species provide strong chemisorption capability and endow intrinsic catalytic sites towards LiPSs, and MoS serves as a nanocrystal to accelerate the reaction dynamics. As a result, MoS/CoS/C/S exhibited high reversible specific capacities at 2C and was maintained at 394 mAh g after 1000 cycles, with a 0.04% capacity decay rate. Impressively, the high reversible specific capacities with high sulfur loading of 4.1 mg cm were maintained at 906.7 mAh g.