Construction of VS2/VOx Heterostructure via Hydrolysis‐Oxidation Coupling Reaction with Superior Sodium Storage Properties

Abstract Heterostructure engineering is one of the most promising modification strategies for reinforcing Na + storage of transition metal sulfides. Herein, based on the spontaneous hydrolysis‐oxidation coupling reaction of transition metal sulfides in aqueous media, a VO x layer is induced and formed on the surface of VS 2 , realizing tight combination of VS 2 and VO x at the nanoscale and constructing homologous VS 2 /VO x heterostructure. Benefiting from the built‐in electric field at the heterointerfaces, high chemical stability of VO x , and high electrical conductivity of VS 2 , the obtained VS 2 /VO x electrode exhibits superior cycling stability and rate properties. In particular, the VS 2 /VO x anode shows a high capacity of 878.2 mAh g −1 after 200 cycles at 0.2 A g −1 . It also exhibits long cycling life (721.6 mAh g −1 capacity retained after 1000 cycles at 2 A g −1 ) and ultrahigh rate property (up to 654.8 mAh g −1 at 10 A g −1 ). Density functional theory calculations show that the formation of heterostructures reduces the activation energy for Na + migration and increases the electrical conductivity of the material, which accelerates the ion/electron transfer and improves the reaction kinetics of the VS 2 /VO x electrode.