Gradient selenium-doping regulating interfacial charge transfer in zinc sulfide/carbon anode for stable lithium...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Metal sulfides are promising anode materials for lithium-ion batteries (LIBs) due to their high theoretical capacity.
• However, poor electronic conductivity and significant volume changes during cycling limit their practical application, causing rapid capacity decay and poor rate performance.

Purpose of the Study:

• To design and fabricate a gradient selenium-doped hollow sandwich structured zinc sulfide/carbon (Se-HSZC) composite as a long-life and stable anode material for LIBs.
• To address the limitations of traditional metal sulfides in LIBs by enhancing charge transfer and mitigating volume expansion.

Main Methods:

• Fabrication of a gradient Se-doped hollow sandwich structured ZnS/C composite (Se-HSZC).
• Electrochemical characterization of the Se-HSZC as an anode material in half-cell and full-cell configurations for LIBs.

Main Results:

• The Se-HSZC anode demonstrated excellent rate capability, achieving 654 mAh g^-1 at 2 A g^-1.
• Remarkable reversible capacity of 567 mAh g^-1 was maintained after 1500 cycles at 4 A g^-1 in a half-cell.
• A full battery utilizing Se-HSZC as the cathode achieved a reversible capacity of 457 mAh g^-1 at 0.5 A g^-1 after 50 cycles.

Conclusions:

• The gradient Se-doping and unique double carbon shell structure significantly enhance interfacial charge transfer and reduce volume expansion.
• The Se-HSZC composite exhibits outstanding long-term stability and rate performance, making it a highly promising anode material for high-performance LIBs.
• This work presents a viable strategy for developing novel metal sulfide nanostructures for advanced energy storage applications.