Fast electrochemical kinetics and strong polysulfide adsorption by a highly oriented MoS2 nanosheet@N-doped carbon interlayer for lithium-sulfur batteries

The polysulfide shuttle effect and sluggish reaction kinetics can severely reduce the sulfur utilization and cycle stability of Li-S batteries, undermining their use in practical applications. Herein, we design a core-shell nanocomposite by encapsulating radially oriented MoS2 nanosheets by porous nitrogen-doped carbon (MoS2@NC) via an eco-friendly method. The highly oriented MoS2 nanosheets in MoS2@NC avoid aggregation of the active sites for polysulfide adsorption, and the desirable integration of the catalytic MoS2 nanosheet core and a highly conductive carbon shell provides a constant flow of electrons to the captured polysulfides for improved polysulfide conversion kinetics. The combined benefits of high polysulfide inhibition and smooth electron and Li+ transfer by a thin layer of MoS2@NC (3.3 m thick) enable a simple sulfur-carbon black cathode with high reversible capacities, good rate performances (876 mA h g(-1) at 3C), an excellent cycle stability over 1500 cycles with a negligible 0.034% decay per cycle, and satisfactory areal capacities with increased sulfur loading (2.0-3.7 mA h cm(-2) at various rates). This work provides a proof-of-concept study on the rational design of interlayer materials in energy storage systems.