Abstract: Tin-based electrode materials have emerged as one of the most promising anode candidates for high-energy-density battery systems due to their high theoretical capacity. However, their large volume expansion and rapid capacity fading during cycling have severely impeded their commercialization. To address these critical challenges, this work ingeniously integrates the high stability of bismuth-based materials with the high capacity of tin-based materials, designing and fabricating a one-dimensional nanorod-structured tin oxide-encapsulated bismuth sulfide (Bi₂S₃@Sn_0.904O₂) nanocomposite. Through process regulation, cationic tin vacancies and anionic sulfur vacancies are rationally introduced, which act in synergy with the heterojunction structure to jointly enhance the lithium storage performance of the electrode. As an anode for lithium-ion batteries, the as-prepared Bi₂S₃@Sn_0.904O₂electrode delivers a reversible capacity of 737.3 mA h g^-1 at a current density of 500 mA g^-1, and maintains a capacity of 656.8 mA h g^-1 after 1500 cycles at 2 A g^-1. More importantly, the underlying mechanism has been systematically elucidated via density functional theory (DFT) calculations. This unique structural design strategy provides important guidance for the construction of high-performance tin-based electrode materials and other metal-based anode materials.

Key words: Bi₂S₃@Sn_0.904O₂, Tin vacancies, Sulfur vacancies, Heterojunction structure, Lithium-ion batteries