Precarbonizing-Directed In Situ Formation of Vacancy-Rich MoS ₂ for High-Performance Li–S Batteries

Lithium–sulfur (Li–S) batteries are regarded as promising candidates for future energy-storage applications due to their high theoretical energy density, yet their practical application is impeded by sluggish polysulfide conversion kinetics and severe shuttle effects. Vacancy engineering in MoS 2 has emerged as an effective strategy for regulating polysulfide adsorption and catalysis, but achieving a high density of structurally stable sulfur vacancies under mild conditions remains challenging. Here, we report a precarbonizing-directed in situ growth approach to construct sulfur-vacancy-rich MoS 2 densely anchored on glucose-derived carbon spheres (MoS 2– x @CS). The resulting hybrid features expanded interlayer spacing, abundant unsaturated Mo sites, and significantly enhanced polysulfide chemisorption, leading to accelerated redox kinetics, reduced polarization, higher Li + transference number, lower charge-transfer resistance, and improved diffusion behavior. DFT calculations further reveal a much stronger adsorption energy for Li 2 S 6 on vacancy-engineered MoS 2 (−4.97 eV) compared with pristine MoS 2 (−1.65 eV). Benefiting from these synergistic effects, Li–S batteries with MoS 2– x @CS deliver high capacities (1256 mAh g –1 at 0.2 C), excellent rate performance (640 mAh g –1 at 5 C), and robust cycling under practical conditions (798 mAh g –1 with 7.5 mg cm –2 sulfur and 6 μL mg –1 E/S). This work offers a mild and potentially extendable route for achieving effective sulfur-vacancy regulation in MoS 2 -based hosts for high-performance Li–S batteries.