Highly Conductive Polyoxanorbornene-Based Polymer Electrolyte for Lithium-Metal Batteries

Area of Science:

• Polymer Chemistry
• Materials Science
• Electrochemistry

Background:

• Solid polymer electrolytes (SPEs) are crucial for developing safer and more efficient lithium-metal batteries (LMBs).
• Traditional SPEs often face challenges with ionic conductivity and interfacial stability.
• Bottlebrush polymers offer unique structural advantages for ion transport.

Purpose of the Study:

• To synthesize and characterize polyoxanorbornene-based bottlebrush polymers with poly(ethylene oxide) (PEO) side chains.
• To investigate the potential of these polymers as solid polymer electrolytes for LMBs.
• To explore the dual ionic conductive pathways for enhanced ion movement.

Main Methods:

• Ring-opening metathesis polymerization (ROMP) was employed for polymer synthesis.
• Ionic conductivity measurements were performed at room temperature.
• Electrochemical performance was evaluated using Li metal anodes and LiFePO4 cathodes.

Main Results:

• The synthesized bottlebrush polymers exhibited high ionic conductivity (7.12 × 10⁻⁴ S cm⁻¹ at room temperature).
• The polymers demonstrated excellent electrochemical performance, including high-rate capabilities and cycling stability.
• The dual ionic conductive pathways (PEO side chains and polyoxanorbornene backbone) effectively promoted Li-ion transport.

Conclusions:

• Polyoxanorbornene-based bottlebrush polymers with PEO side chains represent a promising new class of SPEs.
• The dual ionic conductivity design is a viable strategy for improving ion transport in polymer electrolytes.
• These findings highlight the importance of molecular engineering for advanced lithium-metal battery electrolytes.