Excellent Polymerized Ionic-Liquid-Based Gel Polymer Electrolytes Enabled by Molecular Structure Design and...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Polymerized ionic liquid (PIL)-based gel polymer electrolytes (GPEs) offer safety and stability but suffer from low ionic conductivity.
• Developing GPEs with high ionic conductivity is crucial for advanced energy storage applications, particularly lithium metal batteries.

Purpose of the Study:

• To design and synthesize a novel PIL-based GPE with enhanced ionic conductivity and dendrite suppression capabilities.
• To improve the performance and safety of lithium metal batteries through advanced electrolyte development.

Main Methods:

• Synthesized a novel ionic liquid monomer with a long, flexible side chain.
• Formulated a GPE (GM-GPE) by mixing the monomer with LiTFSI and a plasticizer (MEMPTFSI).
• Characterized the GM-GPE's ionic conductivity, electrochemical stability, thermal stability, and lithium dendrite inhibition properties.

Main Results:

• The GM-GPE achieved high ambient ionic conductivity (4.3 × 10⁻⁴ S cm⁻¹ at 30 °C).
• Demonstrated robust electrochemical and thermal stability, nonflammability, and superior lithium dendrite suppression.
• Achieved a high discharge capacity (150 mA h g⁻¹) with good cycling stability and rate capability in a LiFePO₄|GM-GPE|Li cell.

Conclusions:

• The novel PIL-based GPE (GM-GPE) significantly enhances ionic transport and lithium-ion deposition uniformity.
• The developed GM-GPE provides a promising pathway for high-performance, safe, and long-cycling dendrite-free lithium metal batteries.