Study on Energy Storage of ZnCoS 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 ZnCoS sulfur vacancies by regulating the hydrothermal time and performed density functional theory (DFT) calculations on ZnCoS with vacancies. The results showed that ZnCoS 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 in the first cycle, then maintained at 1,529.8 mAhg after 200 cycles. The excellent cycling performance was attributed to the vacancies that enhanced the carrier transport and adsorption capacity of ZnCoS. Notably, the sulfur vacancy-based surface defect strategy in this study had a greater impact on the electrochemical performance than the morphology optimization strategy.