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, the 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 these structural and catalytic advantages, the S/1T-MoS₂/N-G cathode exhibits an initial capacity of 1296.8 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.