High-performance sodium-ion storage based on glucose-derived S-doped carbon coated Sb/Mo-sulfide composites

The pressing need for low-cost long-cycling sodium-ion batteries （SIBs） for large-scale energy storage underscores the critical importance of high-performance carbon-based anode materials. Targeting the core challenges of severe volume expansion and poor cycling stability in metal sulfide anodes during sodiation/desodiation, this study proposes a facile and green material design strategy. Using glucose （C₆H₁₂O₆） as the carbon source and thioacetamide as the sulfur source, a one-step hydrothermal sulfidation followed by calcination was employed to synthesize a sulfur-doped carbon-coated Sb-Mo-S composite （Sb₂S₃/Mo₂S₃@SC） from a bimetallic oxide precursor for application as an anode in SIBs. Structural and morphological characterizations confirm that with an appropriate ratio of the carbon source, a composite structure consisting of metal sulfide nanoflowers encapsulated by a stable carbon layer was successfully fabricated. This carbon layer not only acts as a mechanical skeleton to effectively buffer volume expansion during cycling and inhibit material pulverization but also significantly enhances electron conduction and optimizes reaction kinetics. Electrochemical tests show that with a precursor （Sb₂MoO₆） to glucose mass ratio of 1∶3, the obtained Sb₂S₃/Mo₂S₃@SC-3 exhibits excellent sodium storage performance. After 200 cycles at a current density of 0.2 A/g and 500 cycles at 1 A/g, the electrode delivered specific capacities of 678.47 and 589.77 mAh/g, respectively, demonstrating exceptional sodium-ion storage capabilities. This anode exhibits reversible capacities of 629.84 and 484.73 mAh/g at 0.05 and 5 A/g, respectively, corresponding to a high-rate capacity. Notably, upon reverting to 0.05 A/g, the specific capacity recovered to 645.36 mAh/g, indicating superb rate performance and structural reversibility. Kinetic analysis further reveals that the charge storage is dominated by pseudocapacitive behavior, accompanied by a high sodium ion diffusion coefficient. This work, through the ingenious cooperative design of carbon coating and sulfur doping, provides a new approach for developing anode materials for SIBs that combine high capacity, long lifespan, and superior rate performance.