Modulating carrier-catalyst heterointerfaces to boost catalytic polysulfide conversion in lithium-sulfur batteries

Enhancing the catalytic activity of sulfur cathode hosts is critical for suppressing the shuttle effect and accelerating the polysulfides redox kinetics in lithium-sulfur (Li-S) batteries. However, efficient polysulfide adsorption and catalysis conversion rely on synergistic interactions between the catalyst and the supporting carrier, particularly in optimizing catalytic site density and electron/ion transport rates. Herein, we modulate the carrier-catalyst heterointerface to enhance polysulfide conversion. Metallic 1T-phase MoS2 nanospheres are uniformly dispersed onto the nitrogen-doped graphene (N-G) sheets, forming a composite host material (1T-MoS2/N-G) for Li-S batteries. N-G serves as both a conductive substrate for charge transfer and a support for catalyst loading, while 1T-MoS2, rich in catalytic sites, functions as an efficient electrocatalyst, promoting ion diffusion, adsorbing soluble polysulfides, and accelerating their transformation into solid lithium sulfide. Benefiting from these structural and catalytic advantages, the S/1T-MoS2/N-G cathode exhibits an initial capacity of 1,296.8 mAh g-1 at 0.2 C and demonstrates outstanding cycle stabilization, with a capacity decay rate of only 0.015% per cycle over 500 cycles at 1.0 C. Even under demanding conditions, such as a sulfur loading of 6.5 mg cm-2 and a lean electrolyte of 7 µL mg-1, the S/1T-MoS2/N-G cathode provides an initial areal capacity of 7.2 mAh cm-2 and retains 4.8 mAh cm-2 after 100 cycles. These findings offer new insights into the design of advanced catalytic materials for high-performance sulfur cathodes and broader electrocatalytic applications.