Phase-Transition Intervention Engineered Amorphous Vanadium Oxide for High-Performance Aqueous Zinc-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Amorphous vanadium oxide (AVO) is a promising cathode for aqueous zinc-ion batteries (AZIBs) due to its high capacity and low cost.
• However, AVO suffers from thermodynamic instability, poor conductivity, and dissolution, limiting its practical use.

Purpose of the Study:

• To develop a novel synthesis strategy for amorphous vanadium oxide (AVO) to overcome its limitations in AZIBs.
• To improve the stability, conductivity, and electrochemical performance of AVO-based cathodes.

Main Methods:

• A "phase-transition intervention" strategy was employed, involving polyaniline intercalation into V₂O₅·1.6H₂O.
• High-temperature treatment induced in situ carbonization of polyaniline, forming nitrogen-doped carbon layers around AVO.

Main Results:

• Nitrogen-doped carbon layers successfully confined AVO, disrupting crystallinity and enhancing stability.
• The composite cathode exhibited suppressed dissolution, improved electrical conductivity, and enhanced thermodynamic stability.
• Exceptional AZIB performance was achieved, with capacities of 390.5 mAh g^-1 at 0.1 A g^-1 and 329.9 mAh g^-1 at 20.0 A g^-1, along with outstanding cycling stability.

Conclusions:

• The "phase-transition intervention" strategy effectively produces stable, conductive amorphous vanadium oxide for high-energy AZIBs.
• This approach offers a versatile route for designing advanced amorphous electrode materials.
• The findings open new avenues for developing next-generation aqueous zinc-ion batteries.