An ionic liquid- and PEO-based ternary polymer electrolyte for lithium metal batteries: an advanced processing...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Solid polymer electrolytes are crucial for next-generation batteries, but challenges remain in achieving high ionic conductivity, safety, and stability.
• Developing solvent-free manufacturing processes is essential for sustainable and scalable electrolyte production.

Purpose of the Study:

• To develop a solvent-free manufacturing process for cross-linked ternary solid polymer electrolytes (TSPEs).
• To investigate the effect of LiTFSI and Pyr14TFSI content on the ionic conductivity, stability, and performance of TSPEs.
• To evaluate the electrochemical performance of TSPEs in various battery cell configurations.

Main Methods:

• Solvent-free processing of ternary electrolytes (PEODA, Pyr14TFSI, LiTFSI).
• Ionic conductivity measurements (>1 mS cm⁻¹).
• Electrochemical testing in Cu‖Li, Li‖Li, and LFP‖Li cells.

Main Results:

• Achieved high ionic conductivity (>1 mS cm⁻¹) in TSPEs.
• Increased LiTFSI content (10 wt% to 30 wt%) significantly reduced short-circuit risk and increased practical areal capacity by over 20x (0.42 to 8.80 mA h cm⁻²).
• Demonstrated high Coulombic efficiencies (93%), limiting current densities (0.46 mA cm⁻²), and excellent thermal stability (>300 °C).
• Achieved a high discharge capacity (150 mA h g⁻¹) in LFP‖Li cells after 100 cycles at 60 °C.

Conclusions:

• The developed solvent-free process yields high-performance TSPEs suitable for advanced battery applications.
• TSPEs exhibit enhanced safety features, including reduced short-circuit risk and high thermal stability.
• The electrolytes show promising electrochemical performance, including high ionic conductivity and capacity retention, paving the way for safer and more efficient batteries.