Construction of ZnS modified N/S-doped straw-based carbon with ultra long lithium storage performance

In lithium-ion battery (LIB), commercial graphite exhibits low-rate capacity and poor cyclic stability. Therefore, the low-cost development of graphite substitutes with high-rate capacity and high cyclic stability has broad application prospects. In this paper, the discarded corn stover work as the raw material, ZnCl ₂ as the zinc source, melamine as nitrogen source, and thiosemicarbazide as sulfur source, fabricating ZnS modified N- and S-doped carbon (ZnS@NSC). As anode materials in LIB, the ZnS composition could improve the capacity of ZnS@NSC. Meanwhile, the NSC components could not only increase the conductivity of the composite, but also buffer the volume changes of ZnS during the charging and discharging processes. As a result, ZnS@NSC exhibits high rate capacity and long-term stability. At 1 A·g ⁻¹, it can still exhibit a capacity of 261.3 mAh·g ⁻¹ in the 700th cycle. This study indicates that ZnS@NSC shows a hybrid lithium storage mechanism including bulk diffusion and pseudocapacitance. In addition, the low initial coulombic efficiency may be attributed to the formation of solid electrolyte interface (SEI) film and the defects on the NSC component. This work provides a reference for designing sulfides and the value-added utilization of waste corn stover.