Engineering sulfur defective Bi₂S₃@C with remarkably enhanced electrochemical kinetics of lithium-ion batteries

Introducing the appropriate vacancies to augment the active sites and improve the electrochemical kinetics while maintaining high cyclability is a major challenge for its widespread application in electrochemical energy storage. Here, core-shell structured Bi₂S₃@C with sulfur vacancies was prepared by hydrothermal method and one-step carbonization/sulfuration process, which significantly improves the intrinsic electrical conductivity and ion transport efficiency of Bi₂S₃. Additionally, the uniform protective carbon layer around surface of composite maintains structural stability and effectively alleviates volume expansion during alloying/dealloying. As a result, the BSC-500 anode exhibits a brilliant reversible capacity of 636 mAh/g at 0.2 A/g and a long-term stable capacity of 524 mAh/g for 500 cycles at a high current density of 3 A/g in lithium-ion batteries. In addition, the assembled Bi₂S₃@C//LiCoO₂ full cell delivered a capacity of 184 mAh/g at 1 A/g and excellent cyclability (125 mAh/g after 1000 cycles). The proposed strategy of combining sulfur vacancies with a core-shell structure to improve the electrochemical kinetics of Bi₂S₃ in lithium-ion batteries off the prospect for practical applications of transition metal sulfide anodes.