Solid Polymer Electrolyte with Compatible Cathode-Electrolyte Interfacial Design Enabling Lithium Metal Batteries...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Lithium metal batteries (LMBs) with solid polymer electrolytes (SPEs) promise higher energy density and safety than Li-ion batteries.
• Achieving long cycle life in LMBs with high-voltage cathodes requires improved cathode-SPE compatibility.

Purpose of the Study:

• To develop a dual-functional poly(ionic liquid) (PolyIL) material acting as both SPE matrix and cathode binder.
• To enhance the cathode-SPE interface for improved electrochemical performance and stability.

Main Methods:

• A dual-functional PolyIL material was synthesized to serve as an SPE matrix and cathode binder.
• A modified cellulose acetate (CA)-based PolyIL substrate with functional groups was incorporated to aid Li+ migration and mechanical strength.
• In situ polymerization was used to assemble the battery cells, optimizing interfacial compatibility.

Main Results:

• The developed PolyIL-based SPE demonstrated high ionic conductivity and a wide electrochemical stability window.
• The Li||LFP cells achieved stable cycling for over 1100 cycles.
• The Li||NCM811 cells operated reliably at a high cut-off voltage of 4.8 V.

Conclusions:

• The dual-functional PolyIL material significantly improves cathode-SPE interface compatibility in LMBs.
• This approach enables long cycle life and high-voltage operation, advancing the development of safer and more energy-dense lithium metal batteries.