Ultralight Electrolyte for High-Energy Lithium-Sulfur Pouch Cells

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• High electrolyte weight fraction limits lithium-sulfur (Li-S) battery specific energy.
• Reducing electrolyte volume in Li-S batteries is challenging due to cathode porosity and Li metal anode depletion.

Purpose of the Study:

• To develop an ultralight electrolyte for Li-S batteries.
• To enable Li-S pouch cell functionality under lean-electrolyte conditions.
• To improve the specific energy of Li-S batteries.

Main Methods:

• Introduction of a weakly-coordinating and Li-compatible monoether to create an ultralight electrolyte (0.83 g mL⁻¹).
• Evaluation of Li-S pouch cells with the ultralight electrolyte under lean-electrolyte conditions.

Main Results:

• Achieved an ultralow electrolyte weight/capacity ratio (E/C) of 2.2 g Ah⁻¹.
• Realized a 19.2% improvement in specific energy (393.4 Wh kg⁻¹ compared to 329.9 Wh kg⁻¹).
• Demonstrated over 20% specific energy improvement across various electrolyte/sulfur ratios (E/S).

Conclusions:

• The ultralight electrolyte significantly reduces the electrolyte weight fraction in Li-S cells.
• This advancement enables high-performance Li-S pouch cells even with reduced electrolyte volumes.
• The developed electrolyte offers a promising pathway to enhance the practical specific energy of Li-S batteries.