Non-Isocyanate Poly(hydroxyurethane)-Based Networks as Solid Polymer Electrolytes for Lithium Metal Batteries

Area of Science:

• Polymer Chemistry
• Materials Science
• Electrochemistry

Background:

• Developing stable and flexible solid polymer electrolytes (SPEs) is crucial for advanced battery technologies.
• Poly(ethylene glycol) (PEG)-based SPEs often face trade-offs between mechanical and electrochemical properties.
• Bio-based materials offer sustainable alternatives for polymer synthesis.

Purpose of the Study:

• To synthesize novel poly(hydroxyurethane) (PHU) networks using bio-based carbonated soybean oil and poly(ethylene glycol) (PEG).
• To investigate the preparation of PHU-poly(epoxy) mixed networks for enhanced properties.
• To evaluate the electrochemical performance and stability of these networks as solid polymer electrolytes for lithium batteries.

Main Methods:

• Facile synthesis of PHU networks via ring-opening of cyclic carbonates on bio-based soybean oil with amine-functionalized PEG.
• Incorporation of epoxide-functionalized PEG segments to form PHU-poly(epoxy) mixed networks.
• Characterization of polymer networks and evaluation of ionic conductivity, oxidation stability, and lithium metal compatibility of resulting SPE membranes.

Main Results:

• Successfully synthesized flexible PHU and PHU-poly(epoxy) networks with good interfacial stability.
• Achieved ionic conductivities in the range of ~10^-4.5 to 10^-5 S/cm at 60°C for SPE membranes.
• Demonstrated high oxidation stability (>4.2 V vs Li/Li+) and excellent long-term cycling stability with lithium metal.

Conclusions:

• PHU-based networks offer a tunable platform for developing high-performance solid polymer electrolytes.
• These materials effectively address the mechanical-electrochemical property trade-offs common in PEG-based SPEs.
• The bio-based origin and versatile synthesis make PHU networks attractive for next-generation lithium battery electrolytes.