Sulfur vacancy and heterojunction synergistic effects in a Bi2S3/ZnS@C composite promote the fast diffusion dynamics of electrons and ions in Li-/Na-ion batteries

Abstract

Addressing the bottleneck of capacity decay in Bi₂S₃ anodes caused by their intrinsic low conductivity and structural instability from Bi–S bond reorganization is a huge challenge. Herein, a synergistic heterojunction–vacancy strategy is proposed and a Bi₂S₃/ZnS@C composite is constructed. The interfacial charge redistribution and sulfur vacancies overcome kinetic hysteresis and cycling deterioration, achieving accelerated ion transfer and reinforced structural integrity in metal sulfide electrodes. BSC/ZSC-2 exhibited exceptional long-term cycling performance as a dual-function anode in both lithium-ion batteries (693.7 mAh g⁻¹ after 1000 cycles at 3 A g⁻¹) and sodium-ion batteries (415.2 mAh g⁻¹ after 500 cycles at 3 A g⁻¹). The assembled lithium-ion full cell BSC/ZSC-2//LiCoO₂ exhibited significant potential in practical applications (432.2 mAh g⁻¹ after 500 cycles at 1 A g⁻¹). The designed strategy effectively advances the energy storage capabilities of Bi₂S₃ and provides new avenues for the structural design of other metal sulfide materials.