A Polymer Electrolyte with Rigid-Flexible Coupled Architecture for High-Voltage Lithium-Metal Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Solid-state lithium-metal batteries require advanced electrolytes for improved safety and performance.
• Current polymer electrolytes often face challenges with ionic conductivity and mechanical stability.

Purpose of the Study:

• To develop a novel polymer electrolyte with enhanced ionic conductivity, mechanical strength, and electrochemical stability.
• To investigate a rigid-flexible coupled architecture for high-voltage lithium-metal battery applications.

Main Methods:

• Solution-casting strategy to integrate a poly(methyl methacrylate) (PMMA)/eutectic electrolyte (EE) phase into a porous polyethylene (PE) scaffold.
• Characterization of the electrolyte's ionic conductivity, lithium-ion transference number, and electrochemical stability window.
• Fabrication and testing of Li||LiFePO4 cells using the developed electrolyte.

Main Results:

• The polymer electrolyte achieved an ionic conductivity of 1.59 × 10⁻⁴ S cm⁻¹ at 30 °C and an electrochemical stability window up to 4.75 V.
• The electrolyte demonstrated a lithium-ion transference number of 0.45 and stable cycling in Li||LiFePO4 cells for 1000 cycles at 3 C with 76.8% capacity retention.
• The unique architecture provided excellent mechanical strength, flexibility, and resistance to lithium dendrite penetration.

Conclusions:

• The developed PMMA/EE in PE scaffold electrolyte offers a promising pathway for high-voltage solid-state lithium-metal batteries.
• The monomer-free design enhances interfacial stability, overcoming limitations of conventional electrolytes.
• This rigid-flexible coupled architecture represents a significant advancement in electrolyte design for next-generation energy storage devices.