Dual functional coordination interactions enable fast polysulfide conversion and robust interphase for high-loading...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• High-capacity lithium-sulfur batteries (LSBs) face challenges due to slow lithium polysulfide (LiPSs) conversion kinetics and unstable lithium metal anodes.
• These issues limit the practical application and long-term stability of LSBs for energy storage.

Purpose of the Study:

• To introduce 6-(dibutylamino)-1,3,5-triazine-2,4-thiol (DTD) as a functional additive to improve LSB performance.
• To investigate the mechanism by which DTD accelerates cathodic conversion and modulates the anode interface.
• To demonstrate enhanced stability and capacity retention in DTD-modified LSBs.

Main Methods:

• Synthesis and incorporation of DTD as an additive in LSBs.
• Electrochemical testing, including cycling performance, rate capability, and Li-Li symmetric cell tests.
• Analysis of the solid electrolyte interface (SEI) and polysulfide redox behavior.

Main Results:

• DTD addition significantly promotes LiPSs redox conversion and forms a synergistic inorganic-organic SEI layer.
• LSBs with DTD exhibit a low capacity decay rate of 0.066% per cycle over 600 cycles at 1C.
• Li-Li symmetric batteries show reduced overpotentials and a 41% increase in cycle life; high sulfur loading LSBs retain 71.5% capacity.

Conclusions:

• DTD effectively accelerates polysulfide conversion and stabilizes the lithium anode interface in LSBs.
• The study provides a new mechanism for understanding polysulfide conversion and SEI regulation in high-energy-density LSBs.
• DTD offers a promising strategy for developing stable and high-performance lithium-sulfur batteries.