Dual-Metal MOF-Derived Carbon Fibers Achieve Efficient Polysulfide Anchoring and Conversion Simultaneously in Li-S...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries offer high energy density but face challenges like polysulfide shuttle and slow redox kinetics.
• These issues hinder the practical application of Li-S batteries for advanced energy storage solutions.

Purpose of the Study:

• To design and synthesize a novel material for Li-S batteries that addresses polysulfide shuttle and sluggish kinetics.
• To improve the electrochemical performance and cycle stability of Li-S batteries.

Main Methods:

• Utilized bimetallic metal-organic frameworks (MOFs) as precursors to synthesize CoS2-ZnS-modified carbon nanofiber networks (CoS2-ZnS@CNF).
• Investigated the synergistic catalytic activity of bimetallic sulfides and the structural benefits of conductive carbon nanofiber networks.
• Performed electrochemical tests to evaluate battery performance under various conditions.

Main Results:

• CoS2-ZnS nanoparticles were uniformly anchored on carbon nanofibers, facilitating strong polysulfide chemisorption and accelerated conversion kinetics.
• The 3D porous carbon nanofiber framework provided physical adsorption sites for polysulfides and enhanced electrode conductivity.
• The CoS2-ZnS@CNF electrode demonstrated excellent stability, retaining 788.5 mAh g-1 after 500 cycles at 0.5 A g-1.
• Achieved an initial discharge capacity of 1042.6 mAh g-1 even with a high sulfur loading of 5.8 mg cm-2.

Conclusions:

• The synergistic effect of bimetallic sulfides and the carbon nanofiber network effectively inhibits polysulfide shuttle and enhances electrochemical performance.
• The developed CoS2-ZnS@CNF material shows significant promise for high-performance Li-S batteries.
• This approach offers a viable strategy for advancing next-generation energy storage systems.