Polymer-Rich Composite Electrolytes for All-Solid-State Li-S Cells

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• All-solid-state batteries offer enhanced safety compared to liquid electrolyte counterparts.
• Developing stable and high-performance electrolytes is crucial for advancing lithium-sulfur (Li-S) battery technology.

Purpose of the Study:

• To investigate polymer-rich composite electrolytes (CPEs) with Li-ion conducting glass ceramic (LICGC) and Al2O3 fillers for all-solid-state Li-S cells.
• To evaluate the impact of these fillers on ionic conductivity, interfacial stability, and electrochemical performance.

Main Methods:

• Fabrication of CPEs using lithium bis(fluorosulfonyl)imide (LiFSI) and poly(ethylene oxide) (PEO) with LICGC or Al2O3 fillers.
• Electrochemical characterization of CPEs, including ionic conductivity measurements.
• Assembly and testing of all-solid-state Li-S cells utilizing the developed CPEs.

Main Results:

• Ionic conductivity of CPEs did not significantly increase with fillers compared to plain LiFSI/PEO.
• Al2O3-filled CPE improved Li/electrolyte interface stability.
• LICGC-based CPE achieved high sulfur utilization (1111 mAh g⁻¹) and areal capacity (1.14 mAh cm⁻²).
• A combined LICGC/Al2O3 CPE cell demonstrated 518 mAh g⁻¹ capacity and >99% Coulombic efficiency at 70 °C over 50 cycles.

Conclusions:

• Composite polymer electrolytes with LICGC and Al2O3 fillers are viable candidates for safe, high-performance all-solid-state Li-S batteries.
• Combining different fillers can synergistically enhance both interfacial stability and electrochemical performance.
• Further development of these CPEs could lead to advanced energy storage solutions.