Turning Soluble Polysulfide Intermediates Back into Solid State by a Molecule Binder in Li-S Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• The shuttle effect of dissolved polysulfides is a critical challenge in lithium-sulfur (Li-S) battery operation.
• This effect leads to capacity fading and reduced cycle life in Li-S batteries.

Purpose of the Study:

• To propose an in situ strategy for forming a functionalized molecule binder (MB) to mitigate the polysulfide shuttle effect.
• To enhance the stability and electrochemical performance of Li-S batteries.

Main Methods:

• In situ formation of a dual-terminal coupling functional molecule binder (MB) from quinhydrone (QH) and lithium.
• Utilizing MB to chemically coordinate and bind dissolved polysulfide intermediates.
• Investigating the copolymerization of MB with polysulfides to form -[MB-Li₂S]- complexes.

Main Results:

• The MB effectively binds polysulfides, preventing their dissolution and shuttle effect.
• Li-S batteries with MB achieved a high initial capacity of 1347 mAh g^-1 at 0.1 C.
• Demonstrated excellent cycling stability with 963 mAh g^-1 remaining after 400 cycles at 1 C and 96.9% retention over 300 cycles.

Conclusions:

• The developed MB strategy successfully resolves the shuttle effect in Li-S batteries.
• This approach offers a promising pathway for achieving high-performance and long-lasting Li-S batteries.
• The findings have potential implications beyond Li-S battery technology.