Synergistic amorphous carbon-coated VS4/VOx nanosheets with rich interfaces endow aqueous zinc-ion batteries with high performance

Abstract

Aqueous zinc-ion batteries have been adopted as the most promising candidates for energy storage devices owing to their low cost, high ionic conductivity, and safety. However, the development of cathode materials with fast kinetics and robust zinc-ions diffusion are the main bottlenecks. Benefiting from the superior conductivity of vanadium sulfide and high chemical stability of vanadium oxide, the amorphous carbon-coated VS₄/VO_x nanosheets integrated with rich interfaces and oxygen vacancies are designed and prepared for boosting Zn²⁺ storage. The VS₄/VO_x@C cathode delivered a high specific capacity of 350 mA h g⁻¹ at 0.1 A g⁻¹, superior rate capacity of 156 mA h g⁻¹ at 10 A g⁻¹, and a record capacity retention of 93% (145 mA h g⁻¹) over 1000 cycles at a high current density of 10 A g⁻¹. In addition, pseudocapacitance-like contribution analysis as well as galvanostatic intermittent titration technique (GITT) further confirmed that the abundant oxygen vacancies, rich interfaces, and heterostructural nanosheets greatly contribute to fast Zn²⁺ diffusion and enhanced reaction kinetics. The strong insight obtained in this study sheds light on a new methodology for exploring the potential of transition metal sulfides-based cathode materials for aqueous zinc-ion batteries.