Anodic Oxidation Strategy toward Structure-Optimized V₂O₃ Cathode via Electrolyte Regulation for Zn-Ion Storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) are promising for large-scale energy storage.
• Development of AZIBs is hindered by the lack of suitable cathode materials.
• Low-valent vanadium sesquioxide (V2O3) has unsuitable properties for effective Zn2+ hosting.

Purpose of the Study:

• To utilize V2O3 as a high-performance cathode material for AZIBs.
• To overcome the limitations of low-valent V2O3 through an in situ anodic oxidation strategy.
• To investigate the mechanism of the anodic oxidation process and its effect on electrochemical performance.

Main Methods:

• An in situ anodic oxidation strategy was employed for V2O3 cathodes.
• Electrolyte concentration and V2O3 morphology were simultaneously regulated.
• Electrochemical performance (capacity, energy density, cycling stability) was evaluated.
• The phase transition mechanism during anodic oxidation was investigated.

Main Results:

• V2O3 was successfully utilized as a cathode material with a theoretical capacity up to 715 mAh g-1.
• An ultra-efficient anodic oxidation process was achieved during the first charge.
• The V2O3 cathode exhibited a high discharging capacity of 625 mAh g-1 at 0.1 A g-1.
• A high energy density of 406 Wh kg-1 and excellent cycling stability (100% retention after 10,000 cycles) were achieved.
• A nearly two-electron transfer process was observed.

Conclusions:

• The in situ anodic oxidation strategy effectively transforms V2O3 into a high-performance cathode for AZIBs.
• This approach enables a high capacity and remarkable cycling stability, addressing key limitations.
• The study provides insights into the phase transition of low-valent V2O3 and offers a design strategy for advanced cathode materials.