W/V Dual-Atom Doping MoS2-Mediated Phase Transition for Efficient Polysulfide Adsorption/Conversion Kinetics in Lithium–Sulfur Battery

The dissolvable polysulfides and sluggish Li₂S conversion kinetics are acknowledged as two significant challenges in the application lithium-sulfur (Li-S) batteries. Herein, we introduce a dual-doping strategy to modulate the electronic structure of MoS₂, thereby obtaining a multifunctional catalyst that serves as an efficient sulfur host. The W/V dual single-atom-doped MoS₂ grown on carbon nanofibers (CMWVS) demonstrates a strong adsorption ability for lithium polysulfides, suppressing the shuttle effects. Additionally, the doping process also results in the phase transition from 2H-MoS₂ to 1T-MoS₂ and generates sufficient edge sulfur atoms, promoting the charge/electron transfer and enriching the reaction sites. All these merits contribute to the superior conversion reaction kinetics, leading to the outstanding Li-S battery performance. When fabricated as cathodes by compositing with sulfur, the CMWVS/S cathode delivers a high capacity of 1481.7 mAh g^-1 at 0.1 C (1 C = 1672 mAh g^-1) and maintains 816.3 mAh g^-1 after 1000 cycles at 1.0 C, indicating outstanding cycling stability. Even under a high sulfur loading of 7.9 mg cm^-2 and lean electrolyte conditions (E/S ratio of 9.0 μL mg^-1), the cathode achieves a high areal capacity of 8.2 mAh cm^-2, showing great promise for practical Li-S battery applications. This work broadens the scope of doping strategies in transition-metal dichalcogenides by tailoring their electronic structures, providing insightful direction for the rational development of high-efficiency electrocatalysts for advanced Li-S battery applications.