Interchain-Expanded Vanadium Tetrasulfide with Fast Kinetics for Rechargeable Magnesium Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Magnesium batteries offer cost-effective, safe energy storage but suffer from slow Mg²⁺ kinetics in cathodes.
• Improving Mg²⁺ mobility is crucial for enhancing electrochemical performance.

Purpose of the Study:

• To optimize VS₄@reduced graphene oxide (VS₄@rGO) cathode materials by expanding interchain distances.
• To enhance ion diffusivity and electrochemical performance in magnesium batteries.

Main Methods:

• Combined theoretical calculations and experimental investigations.
• Structural modification of VS₄@rGO to increase interchain spacing.
• Electrochemical performance testing including capacity, rate capability, and cycling stability.

Main Results:

• Successfully expanded interchain distance in VS₄@rGO, facilitating MgCl⁺ intercalation.
• Achieved a high capacity of 268.3 mA h g^-1 at 50 mA g^-1 and 85.9 mA h g^-1 at 2000 mA g^-1.
• Demonstrated excellent cycling stability (147.2 mA h g^-1 after 100 cycles) and a wide operating temperature range (-35 to 55 °C).

Conclusions:

• Optimized VS₄@rGO exhibits fast MgCl⁺ kinetics, overcoming Mg²⁺ sluggishness.
• The material shows significant potential for high-performance magnesium batteries.
• The strategy of expanding interchain distance is effective for improving cathode material performance.