In-situ sintering induced VO₂/V₂O₅ heterostructure as cathode for high-capacity reversible aqueous Zn-ion batteries

In this study, VO₂/V₂O₅ heterostructures were successfully prepared by a hydrothermal and in-situ sintering procedure and were studied as aqueous zinc ion batteries (AZIBs). The novel heterostructure plays a critical role in controlling electrochemical performance. X‒ray diffraction analysis showed that the heterostructures were composed mainly of the orthorhombic VO₂ and monoclinic V₂O₅ phases. Compared with pristine VO₂ and V₂O₅, the VO₂/V₂O₅ heterostructure showed excellent electrochemical properties when applied as a cathode for AZIBs. The cathode materials showed a high specific capacity of 453.6 mA h g⁻¹ at 0.2 A g⁻¹, considerable rate performance and capacity retention of 85.6% after 800 cycles at a scan rate of 1 A g⁻¹. The X‒ray photoelectron spectra indicated the chemical components and elemental valence and the impedance analysis indicated the charge transfer kinetics. The method proposed herein provides a strategy for designing AZIBs with high capacity and fast ion diffusion rate.