MXene-Stabilized VS₂ Nanostructures for High-Performance Aqueous Zinc Ion Storage

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Aqueous zinc-ion batteries (AZIBs) are promising for large-scale energy storage due to safety and cost.
• Vanadium-based electrode materials face challenges like poor cyclability and low-rate performance, hindering commercialization.

Purpose of the Study:

• To engineer a stable and high-performance electrode material for AZIBs by creating a 2D heterogeneous layered structure.
• To enhance the electrochemical properties of vanadium disulfide (VS₂) nanosheets through integration with MXene.

Main Methods:

• Incorporation of VS₂ nanosheets into MXene interlayers using nanostructure engineering to form a VS₂/Ti₃C₂T<0xE1><0xB5><0xA_> composite.
• Fabrication of a free-standing composite film for use as both cathode and anode in AZIBs.
• Assembly and testing of flexible Zn-metal-free in-plane AZIBs using the composite material.

Main Results:

• The VS₂/Ti₃C₂T<0xE1><0xB5><0xA_> composite exhibits a stable 2D heterogeneous layered structure with enhanced interlayer spacing.
• The cathode demonstrates a high specific capacity of 285 mAh g⁻¹ at 0.2 A g⁻¹.
• Flexible AZIBs achieved a high operating voltage of 2.0 V and excellent cycling stability with 97% capacity retention after 5000 cycles.

Conclusions:

• Nanocomposite engineering effectively enhances the stability and electrochemical performance of VS₂ for Zn²⁺ storage in AZIBs.
• The VS₂/Ti₃C₂T<0xE1><0xB5><0xA_> composite shows superior performance compared to most reported vanadium-based electrodes for AZIBs.
• This work paves the way for advanced composite materials in rechargeable energy storage applications.