A Novel Single-Ion-Conducting Polymer Electrolyte Derived from CO₂-Based Multifunctional Polycarbonate

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Development of safe and efficient electrolytes is crucial for advanced lithium batteries.
• Polymer electrolytes offer potential advantages over liquid electrolytes, including improved safety and mechanical stability.
• CO2 utilization in polymer synthesis presents an environmentally conscious approach.

Purpose of the Study:

• To synthesize a novel, environmentally friendly, CO2-based single-ion-conducting polymer electrolyte.
• To investigate the electrochemical performance and properties of the synthesized polymer electrolyte.
• To provide a new design strategy for all-solid-state electrolytes for lithium batteries.

Main Methods:

• Terpolymerization of CO2, propylene epoxide (PO), and allyl glycidyl ether (AGE) using zinc glutarate (ZnGA) catalyst.
• Functionalization of the resulting poly(propylene carbonate allyl glycidyl ether) (PPCAGE) via thiol-ene click reaction with 3-mercaptopropionic acid.
• Incorporation of lithium ions by reacting with lithium hydroxide to create single-ion-conducting polymer electrolytes.
• Characterization using 1H NMR, differential scanning calorimetry (DSC), and electrochemical testing.

Main Results:

• Successfully synthesized PPCAGE terpolymers with varying alkene content and low glass transition temperatures (<11.0 °C).
• Developed single-ion-conducting polymer electrolytes with high ionic conductivity (1.61 × 10-4 S/cm at 80 °C) and high lithium ion transference number (0.86) for the 41.0 mol % lithium-containing sample.
• Demonstrated excellent electrochemical stability up to 4.3 V vs Li+/Li.

Conclusions:

• The facile and efficient synthesis of CO2-based multifunctional polycarbonate single-ion-conducting polymer electrolytes is achieved.
• The synthesized polymer electrolytes exhibit promising electrochemical performance, including high ionic conductivity and stability.
• This work presents a viable design strategy for developing advanced all-solid-state electrolytes for various lithium battery applications.