Solvent and catalyst free vitrimeric poly(ionic liquid) electrolytes

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Conventional lithium ion batteries (LiBs) face safety limitations and short lifespans.
• Polymer electrolytes (PEs) offer a safer alternative, with self-healing properties further extending battery life and reducing environmental impact.
• Reprocessable and self-healable materials are crucial for sustainable energy storage solutions.

Purpose of the Study:

• To develop a solvent-free, self-healable, and reprocessable polymer electrolyte (PE) for enhanced lithium ion battery (LIB) performance and safety.
• To create a vitrimeric poly(ionic liquid) (PIL) utilizing dynamic boronic ester bonds for improved material properties.
• To explore the potential of these advanced PEs for 3D printing and novel battery architectures.

Main Methods:

• Synthesis of poly(ionic liquid)s (PILs) using pyrrolidinium-based repeating units and PEO-functionalized styrene as a co-monomer.
• Incorporation of pendant OH groups and boric acid to form dynamic boronic ester bonds, creating a vitrimeric material.
• Characterization of PILs' conductivity, thermal stability, reprocessability, self-healing ability, and rheological properties for 3D printing via fused deposition modeling (FDM).

Main Results:

• A series of vitrimeric PILs were successfully synthesized and characterized by varying monomer ratios and lithium salt (LiTFSI) content.
• The optimized PIL composition achieved an ionic conductivity of 10^-5 S cm^-1 at 50 °C.
• The PILs exhibited excellent reprocessability (at 40 °C), self-healing capabilities, and suitable melt flow behavior (above 120 °C) for 3D printing.

Conclusions:

• The developed vitrimeric poly(ionic liquid)s represent a significant advancement in polymer electrolyte technology for safer and more durable lithium ion batteries.
• The material's self-healing, reprocessable, and 3D printing capabilities open new avenues for designing complex and sustainable battery architectures.
• This work addresses key challenges in battery technology, contributing to cost reduction and environmental sustainability in energy storage.