Sulfur-Defect-Induced TiS_1.94 as a High-Capacity and Long-Life Anode Material for Zinc-Ion Batteries

Aqueous zinc-ion batteries (ZIBs) are competitive among the elective candidates for electrochemical energy storage systems, but the intrinsic drawbacks of zinc metal anodes such as dendrites and corrosion severely hinder their large-scale application. Developing alternative anode materials capable of high reversibility and stability for storing Zn²⁺ ions is a feasible approach to circumvent the challenge. Herein, a sulfur-defect-induced TiS_1.94 (D-TiS_1.94) as a promising intercalation anode material for ZIBs is designed. The abundant Zn²⁺-storage active sites and lower Zn²⁺ migration barrier induced by sulfur defects endow D-TiS_1.94 with a high capacity for Zn²⁺-storage (219.1 mA h g^-1 at 0.05 A g^-1) and outstanding rate capability (107.3 mA h g^-1 at 5 A g^-1). In addition, a slight volume change of 8.1% is identified upon Zn²⁺ storage, which favors a prolonged cycling life (50.3% capacity remaining in 1500 cycles). More significantly, the D-TiS_1.94||ZnMnO₂ full battery demonstrates a high discharge capacity of 155.7 mA h g^-1 with a capacity retention of 59.8% in 400 cycles. It has been estimated that the high-capacity, low-operation voltage, and long-life D-TiS_1.94 can be a promising component of the ZIB anode material family, and the strategy proposed in this work will provide guidance to the defect engineering of high-performance electrode materials toward energy storage applications.