Harnessing structural reconstruction to enhance the electrochemical stability and performance of VS<sub>2</sub> for aqueous zinc-ion storage.

Abstract

Layered VS₂ with large interlayer spacing and high conductivity is a promising cathode for aqueous zinc-ion batteries (AZIBs) but suffers from structural instability. Here, a VS₂/MnS hybrid is designed to stabilize the VS₂ framework through electrochemically induced structural reconstruction. Rietveld refinement of neutron diffraction data confirms the coexistence of hexagonal 1T-VS₂ and cubic MnS, with VS₂ as the dominant phase. Operando synchrotron radiation X-ray diffraction reveals gradual MnS dissolution during the first charge and limited Mn incorporation into VS₂, forming a stable Mn-intercalated phase (VS₂-Mn). X-ray absorption spectroscopy and density functional theory demonstrate that VS₂-Mn exhibits improved structural stability, electrical conductivity, and electron-transfer capability. Benefiting from this reconstruction, the VS₂-Mn electrode delivers a high capacity of 297.9 mAh g^-1 at 0.1 A g^-1, outstanding cycling stability (78.6% after 3,000 cycles at 10 A g^-1), and excellent rate capability. This study highlights structural reconstruction as an effective route to design advanced AZIB cathodes.