Anchoring Atomic Phosphorus in a Mixed Occupancy Cu─S Framework for Ultra-Stable and High-Rate Sodium Storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Phosphorus anodes offer high theoretical capacity for sodium-ion batteries.
• Challenges include low conductivity, volume expansion, and poor kinetics.

Purpose of the Study:

• To develop a stable and high-rate anode material for sodium-ion batteries.
• To address the limitations of pure phosphorus anodes.

Main Methods:

• Fabrication of a novel CuPS2 anode by embedding phosphorus into a Cu─S framework.
• In situ and ex situ analyses to study reaction mechanisms.
• Electrochemical testing to evaluate performance.

Main Results:

• The CuPS2 anode exhibits stable and high-rate sodium-ion storage.
• Achieved a capacity of 583.8 mAh g-1 at 0.2 A g-1.
• Demonstrated 370 mAh g-1 at 5 A g-1 after 11,000 cycles with 90% retention.

Conclusions:

• The rigid and conductive (Na3+x)CuS2 matrix enhances structural stability and reaction kinetics.
• The CuPS2 anode with mixed Cu and P occupancy is a promising material for next-generation sodium-ion batteries.