Interface-stabilized gel polymer electrolyte for high-performance lithium metal batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Lithium metal batteries require electrolytes with high ionic conductivity, mechanical robustness, and interfacial stability.
• Existing electrolytes often struggle to balance these critical properties for high-performance applications.

Purpose of the Study:

• To engineer a novel composite gel polymer electrolyte (GPE) for advanced lithium metal batteries.
• To enhance ionic conductivity, mechanical strength, and interfacial stability through a unique material composition.

Main Methods:

• Fabrication of a GPE using cyano-functionalized polysiloxane (PCMS) frameworks, diethylene glycol dimethyl ether (DEGDME) plasticizers, and electrospun polyacrylonitrile (PAN) nanofiber scaffolds.
• Characterization of ionic conductivity, Li+ transference number, mechanical strength, and electrochemical stability window.
• Performance evaluation in LiFePO4/GPE/Li and NCM811/GPE/Li full cells.

Main Results:

• The optimized GPE achieved high ionic conductivity (3.3 × 10⁻³ S cm⁻¹ at 30 °C), a high Li+ transference number (0.79), and remarkable mechanical strength (3.9 MPa).
• The GPE exhibited a wide electrochemical stability window (5.3 V) and stable lithium plating/stripping for 1000 hours.
• Full cells demonstrated excellent cycling stability, with LiFePO4 cells retaining 94.9% capacity after 500 cycles and NCM811 cells delivering 153.8 mAh g⁻¹ with 86.5% retention after 150 cycles.

Conclusions:

• The developed GPE offers a promising strategy for high-performance lithium metal batteries.
• The cyano-functionalized polysiloxane composite structure facilitates robust solid electrolyte interphase formation and enhances electrochemical performance.
• This work presents a scalable approach for creating advanced electrolytes for next-generation energy storage devices.