Anion and Cation Co-Modified Vanadium Oxide for Cathode Material of Aqueous Zinc-Ion Battery

Abstract

Aqueous zinc-ion batteries (ZIBs) have been regarded as a promising alternative to traditional lithium-based batteries due to their intrinsic advantages of safety, low cost, and abundance. However, the strong electrostatic interaction between Zn2+ and the layer-structured cathodes is still a key issue that hinders the batteries from storing more Zn. Herein, we report partially nitrided and cation-doped vanadium oxide for improved Zn storage performance. Specifically, the defects and nitride species that are generated inside the material upon nitriding improve the conductivity of the material and introduce a new Zn storage mechanism. The intercalation of cations, in contrast, widens the interlayer spacing to store more Zn2+ ions and enhances the cycling stability of the material. These merits synergistically lead to significantly enhanced electrochemical Zn2+ ion storage performance, in terms of a high specific capacity of 418.5 mAh·g−1 at a current density of 0.1 A·g−1 and a capacity retention of 81.2% after 500 cycles at 2.0 A·g−1. The new modification strategy for V2O5 suggested in this work could provide insight into the development of high-performance ZIBs.