Function-Oriented Electrolyte Additives: Chemical Strategy to Enhance the Performance of Lithium-Sulfur Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries offer high theoretical energy density but suffer from practical limitations.
• Key challenges include the polysulfide shuttle effect, sluggish kinetics, material loss, and lithium dendrite formation.
• Electrolyte additives present a promising strategy to mitigate these issues.

Purpose of the Study:

• To review functional electrolyte additives for Li-S batteries.
• To classify additives based on their structure and composition.
• To elucidate the action mechanisms of these additives in enhancing battery performance.

Main Methods:

• Classification of additives into inorganic, organic, ionic liquid, and polymer-based categories.
• Analysis of additive effects on sulfur cathodes (sulfur fixation, CEI layer construction, redox pathway alteration, Li₂S deposition).
• Summary and comparison of additive roles in SEI layer formation, ion migration, and dendrite inhibition on lithium metal anodes.

Main Results:

• Additives effectively address sulfur cathode issues like the shuttle effect and material degradation.
• Functional additives promote stable SEI layer formation on lithium anodes, crucial for dendrite suppression.
• Different additive types exhibit varied mechanisms for improving Li-S battery performance.

Conclusions:

• Electrolyte additives are vital for advancing Li-S battery technology.
• Understanding additive mechanisms provides insights for designing highly stable and efficient Li-S batteries.
• Future research should focus on novel additive development and optimization for practical applications.