Designing Moderately-Solvating Electrolytes for High-Performance Lithium-Sulfur Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• High-energy lithium-sulfur batteries (LSBs) are hindered by electrode instability and polysulfide (PSs) shuttling.
• Developing advanced electrolytes is crucial for overcoming these limitations and enabling large-scale LSB applications.

Purpose of the Study:

• To demonstrate a novel electrolyte design principle for enhanced lithium-sulfur battery performance.
• To create a well-balanced electrolyte system that improves cycle life and stability.

Main Methods:

• Designed moderately solvating electrolytes (MSEs) using a multiple-solvent system (highly, weakly, and non-solvating solvents).
• Investigated the passivation layer formation on Li metal and S electrodes.
• Evaluated battery performance, including cycle life and calendar life.

Main Results:

• The optimal MSE achieved 300 cycles, twice the performance of conventional electrolytes.
• Demonstrated stable calendar life for at least seven months.
• Observed formation of robust passivation layers on electrodes, enhancing structural integrity.

Conclusions:

• The MSE design principle effectively suppresses parasitic side reactions and self-discharge.
• This approach offers a versatile strategy for improving LSB stability and efficiency.
• The findings provide a promising pathway for advancing battery technology beyond LSBs.