Engineering Functional Interface with Built-in Catalytic and Self-Oxidation Sites for Highly Stable Lithium-Sulfur...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries offer high theoretical energy density but suffer from the polysulfide shuttle effect.
• Improving active material utilization and cycle stability is crucial for practical Li-S battery applications.

Purpose of the Study:

• To engineer a functional separator interface for Li-S batteries.
• To accelerate the redox conversion of lithium polysulfides (LiPS) and mitigate the shuttle effect.
• To enhance the electrochemical performance and stability of Li-S batteries.

Main Methods:

• Preparation of graphene-wrapped MnCO3 nanowire (G@MC) composite.
• Utilizing G@MC to modify the separator interface in Li-S batteries.
• Theoretical calculations to investigate LiPS anchoring and reaction mechanisms.
• Electrochemical testing to evaluate battery performance and cycle stability.

Main Results:

• G@MC effectively anchors LiPS via Mn-S chemical bonds, confirmed by theoretical calculations.
• The G@MC interface accelerates LiPS conversion through catalytic Mn2+ sites and graphene's conductivity.
• Li-S batteries with G@MC exhibited minimal capacity decay (0.038% per cycle) over 1000 cycles at 2.0 C.

Conclusions:

• G@MC serves as an effective integrated functional interface for stable Li-S batteries.
• The G@MC material demonstrates potential for advancing high-performance energy storage solutions.
• This work provides insights into designing advanced separators for next-generation batteries.