Cobalt-Mediated Defect Engineering Endows High Reversible Amorphous VS₄ Anode for Advanced Sodium-Ion Storage

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Metal sulfides are promising anode materials for sodium-ion batteries (SIBs) due to their high theoretical capacity.
• However, poor structural stability and sluggish kinetics lead to capacity decay and hinder practical applications.

Purpose of the Study:

• To develop a cobalt-doped amorphous VS4 wrapped by reduced graphene oxide (Co0.5-VS4/rGO) for improved SIB performance.
• To investigate the effect of cobalt doping and defect engineering on the electrochemical properties of VS4.

Main Methods:

• Co-induced defect engineering strategy to synthesize Co0.5-VS4/rGO.
• Electrochemical testing of the material as an anode in SIBs and sodium-ion capacitors.
• Analysis of structure-property relationships.

Main Results:

• Co0.5-VS4/rGO exhibits excellent rate capacities over 10 A g-1 and superior cycling stability at 5 A g-1 over 1600 cycles.
• The enhanced performance is attributed to defects from Co doping, the amorphous structure, and the rGO substrate.
• The material also shows promise in sodium-ion capacitors.

Conclusions:

• Cobalt doping and defect engineering effectively boost the kinetics and stability of VS4 for sodium storage.
• Amorphous metal sulfides, particularly Co0.5-VS4/rGO, are promising electrode materials for advanced batteries and capacitors.
• This study provides insights into preparing amorphous functional materials for energy storage.