Boosting High-Performance in Lithium-Sulfur Batteries via Dilute Electrolyte

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Lithium-sulfur (Li-S) batteries face challenges like polysulfide shuttle, material loss, and resistive layer formation, hindering adoption.
• Increasing electrolyte molarity is a known strategy to improve Li-S battery performance.
• Dilute electrolytes are generally considered detrimental due to increased polysulfide dissolution.

Purpose of the Study:

• To investigate the performance of dilute LiTFSI/DME/DOL/LiNO3 electrolytes in Li-S cells.
• To challenge the conventional understanding of dilute electrolyte behavior in Li-S batteries.
• To demonstrate the potential of dilute electrolytes for high sulfur loading and low electrolyte/sulfur ratios.

Main Methods:

• Utilized a dilute electrolyte formulation (0.1 mol L-1 LiTFSI in DME/DOL with 1 wt. % LiNO3).
• Evaluated electrode wetting, high-rate capability, and cycle performance in Li-S cells.
• Analyzed the suppression of polysulfide dissolution and shuttle effects.

Main Results:

• The dilute electrolyte demonstrated excellent electrode wetting.
• Significantly improved high-rate capability was observed.
• Stable cycle performance was achieved with high sulfur loading and low electrolyte/sulfur ratios.
• Effective suppression of short-chain polysulfide dissolution and shuttle effects was confirmed.

Conclusions:

• Dilute LiTFSI/DME/DOL/LiNO3 electrolytes show outstanding capabilities for Li-S batteries.
• These electrolytes effectively mitigate polysulfide shuttle and dissolution issues.
• The findings open new avenues for designing advanced Li-S battery electrolytes.