Study on Energy Storage of ZnCo₂S_x Based on Sulfur Vacancy Modulation of Ion Transport Rate

Nowadays, high-rate, high-cycle anode materials for lithium batteries are a research hotspot, and defect engineering for electronic structure modulation is expected to be an effective strategy to improve electrochemical performance. In this paper, we controlled the concentration of ZnCo₂S₄ sulfur vacancies by regulating the hydrothermal time and performed density functional theory (DFT) calculations on ZnCo₂S_3.125 with vacancies. The results showed that ZnCo₂S_3.125 exhibited metallic properties, and the vacancies helped to accelerate the diffusion of carriers and improve the storage capacity. The discharge capacity of ZCS-6 initially reached 2,503.2 mAhg^-1 in the first cycle, then maintained at 1,529.8 mAhg^-1 after 200 cycles. The excellent cycling performance was attributed to the vacancies that enhanced the carrier transport and adsorption capacity of ZnCo₂S_x. Notably, the sulfur vacancy-based surface defect strategy in this study had a greater impact on the electrochemical performance than the morphology optimization strategy.