Regulated Electronic and Ionic Conductive Framework for High Energy Density Lithium-Sulfur Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• High energy density in lithium-sulfur (Li-S) batteries is limited by challenges like low conductivity and polysulfide shuttling in thick cathodes with lean electrolytes.
• These issues hinder battery performance, necessitating innovative solutions for practical applications.

Purpose of the Study:

• To design and fabricate a regulated electronic and ionic conductive framework for high-performance Li-S batteries.
• To address the critical challenges of conductivity, polysulfide shuttling, and mechanical instability in Li-S battery cathodes.

Main Methods:

• A layer-by-layer approach was used to integrate carbon nanotubes (CNTs) and sulfur onto air plasma-treated aramid fibers (APAF), forming a CNT/S/APAF composite.
• This composite was incorporated into a CNT network to create free-standing sulfur cathodes for Li-S batteries.

Main Results:

• The CNT/S/APAF cathodes demonstrated enhanced electron transport, electrolyte wettability, and suppressed polysulfide diffusion.
• Achieved an initial specific capacity of 1437.6 mAh g^-1 and areal capacity of 11.3 mAh cm^-2 at a high sulfur loading (7.83 mg cm^-2) and low E/S ratio (5 μL mg^-1).
• The Li-S cells reached an energy density of 468.6 Wh kg^-1 and maintained 6.5 mAh cm^-2 after 100 cycles.

Conclusions:

• The developed conductive framework effectively mitigates performance limitations in Li-S batteries.
• This scalable approach offers a practical and high-performance solution for next-generation energy storage devices.