Binary Transition-Metal Sulfides/MXene Synergistically Promote Polysulfide Adsorption and Conversion in Lithium–Sulfur Batteries

Abstract

Currently, severe shuttle effects and sluggish conversion kinetics are the main obstacles to the advancement of lithium–sulfur (Li–S) batteries. Modification of the battery separator by a catalyst is a promising approach to tackle these problems, but simultaneously obtaining rich catalytic active sites, high conductivity, and remarkable stability remains a great challenge. Herein, a flower-like MXene/MoS2/SnS@C heterostructure as the functional intercalation of Li–S batteries was prepared for accelerating the synergistic adsorption-electrocatalysis of sulfur conversion. The MXene skeleton constructs a three-dimensional conductive network that anchors polysulfides and enhances charge transfer. Meanwhile, the MoS2/SnS has rich active sites for accelerating polysulfide conversion, leading to excellent electrochemical performances. A battery with MXene/MoS2/SnS@C displays an extraordinary capacity of 836.1 mAh g–1 over 200 cycles at 0.5C and demonstrates a remarkable cycling stability with a capacity attenuation of approximately 0.051% per cycle during 1000 cycles at 2C. When the sulfur loading reaches 5.1 mg cm–2, the capacity still maintains 722.4 mAh g–1 over 50 cycles. This research proposes a novel strategy to design stable catalysts for Li–S batteries with an extended lifespan.