Construction interlayer structure of hydrated vanadium oxides with tunable P-band center of oxygen towards enhanced aqueous Zn-ion batteries

Abstract

Layered materials with adjustable framework, as the most potential cathode materials for aqueous rechargeable zinc ion batterie, have high capacity, permit of rapid ion diffusion, and charge transfer channels. Previous studies have widely investigated their preparation and storage mechanism, but the intrinsic relationship between the structural design of layered cathode materials and electrochemical performance has not been well established. In this work, based on the first principles calculations and experiments, a crucial strategy of pre-intercalated metal-ions in vanadium oxide interlayer with administrable p-band center (ɛ_p) of O is explored to enhance Zn²⁺ storage. This regulation of the degree of covalent bond and the average charge of O atoms varies the binding energy between Zn²⁺ and O, thus affecting the intercalation/de-intercalation of Zn²⁺. The present study demonstrates that ɛ_p of O can be used as an important indicator to boost Zn²⁺ storage, which provides a new concept toward the controlled design and application of layered materials.