Polyvinyl Chloride-Derived Organosulfur Cathodes for Durable Li-S Battery

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Lithium-sulfur (Li-S) batteries offer high theoretical energy density but suffer from short cycle life due to the lithium polysulfide (LiPS) shuttle effect.
• Effective host materials are crucial for trapping LiPS and improving battery performance.

Purpose of the Study:

• To develop a novel polymeric host material derived from polyvinyl chloride (PVC) for Li-S batteries.
• To investigate the ability of this material to mitigate the LiPS shuttle effect and enhance battery longevity.

Main Methods:

• Synthesis of a unique PVC-derived polymeric host material (XC).
• Fabrication of XC/sulfur composite cathodes for Li-S batteries.
• Electrochemical testing, including cycling performance, capacity retention, and high sulfur loading evaluations.

Main Results:

• The XC host demonstrated strong chemical and physical confinement of sulfur and LiPS intermediates.
• Li-S batteries utilizing the XC host achieved over 500 cycles with only 9.3% capacity loss (74.4% after 1000 cycles).
• A composite with high sulfur loading (6.2 mg-S/cm²) maintained 67.5% capacity after 200 cycles.

Conclusions:

• The XC polymeric host effectively suppresses the shuttle effect by immobilizing LiPS intermediates.
• This material enables high-capacity, long-cycle-life Li-S batteries, even under demanding conditions.
• The XC host facilitates efficient solid-liquid-solid conversion, ensuring high discharge voltage and energy density.