Oxygen Self-Doping Bi₂S₃@C Spheric Successfully Enhanced Long-Term Performance in Lithium-Ion Batteries

High theoretical capacity of Bi₂S₃ propels it toward an ideal anode material for lithium-ion batteries (LIBs); however, rapid capacity attenuation and poor long-term stability are major barriers to widespread application. In this work, an oxygen self-doping strategy was utilized to synthesize O-Bi₂S₃@C, significantly increasing the amount of active sites for lithium-ion storage. Meanwhile, sulfur vacancies were formed to improve the electrical conductivity and ionic transport efficiency, enhance the long-term stability, and accelerate the electrochemical kinetics of Bi₂S₃@C. O-BSC-S1:3 anode exhibits a reversible capacity of 673.1 mAh g^-1 at 0.2 A g^-1. It retains a long-term capacity of 596.3 mAh g^-1 over 1100 cycles at a high density of 3 A g^-1 in LIBs. Moreover, the installed O-Bi₂S₃@C//LiCoO₂ full battery offers exceptional reversible capacity and remarkable cyclability (325.2 mAh g^-1 after 200 cycles) at 0.2 A g^-1. The combined strategy of oxygen self-doping and sulfur vacancy effectively enhances the reversible capacity and cycling life of Bi₂S₃, providing an approach for the design of high-performance transition metal sulfide anodes for LIBs.