Carbon-coated hydrated vanadium dioxide for high-performance aqueous zinc-ion batteries

Abstract

Rechargeable aqueous zinc-ion batteries (AZIBs) show enormous potential in large-scale energy supply and storage attribute to safety and economy. However, the slow transport dynamics and unstable structural stability of the conventional cathodes hinder the further development of AZIBs. In this work, carbon-coated hydrated vanadium dioxide (HVO@C) was prepared by a one-step hydrothermal method. The introduction of water molecules provides suitable ambient spacing for rapidly accommodating and transporting cations, the coating of carbon further stabilizes the structure of the material and improves the conductivity of the material. The synergistic merits of pre-intercalated water molecules and carbon encapsulation are beneficial for both electron and ion transport kinetics. And the content of water molecules is controlled by regulating V/C ratio. Electrochemical results revealed that the H1.99VO@C/Zn batteries yield a good reversible specific capacity (329.0 mA h g−1 at 1 A g−1) with superior cycling stability (174.2 mA h g−1 at 5 A g−1 after 1000 cycles). This work provides a strategy for developing safe and high-performance energy storage equipment by pre-intercalated defect and carbon encapsulation.