Reinforced Quaternized Poly(crown ether)-Based Solid Polymer Electrolyte for Highly Durable Lithium-Metal Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• All-solid-state lithium metal batteries (LMBs) offer high energy density and safety.
• Solid polymer electrolytes (SPEs) in LMBs suffer from low ionic conductivity and poor Li+ transference, causing dendrite growth and interfacial issues.

Purpose of the Study:

• To develop a mechanically reinforced composite solid polymer electrolyte (QPCE-SPE) for improved LMB performance.
• To address challenges of low ionic conductivity and Li+ transference in conventional SPEs.

Main Methods:

• Fabrication of QPCE-SPE by impregnating a PEO/LiTFSI matrix with quaternized poly(crown ether) into a porous polypropylene substrate.
• Characterization of ionic conductivity, Li+ transference number, and electrochemical performance in Li symmetric and LiFePO4 (LFP)//Li cells.

Main Results:

• QPCE-SPE achieved an ionic conductivity of 1.05 × 10^-4 S cm^-1 at 80 °C and a Li+ transference number of 0.56.
• Stable cycling (>1300 h) in Li symmetric cells and excellent capacity retention (81.9% after 1000 cycles) in Li|QPCE-SPE|LFP batteries.
• Demonstrated mechanical resilience and intrinsic safety under abuse conditions.

Conclusions:

• The developed QPCE-SPE effectively enhances ionic conductivity and Li+ transport in solid polymer electrolytes.
• This composite electrolyte presents a viable strategy for high-performance and safe all-solid-state lithium metal batteries.
• The mechanical reinforcement and chemical design contribute to overcoming critical limitations in current SPE technology.