Ultrathin Aramid/COF Heterolayered Membrane for Solid-State Li-Metal Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Solid-state polymer-based composite electrolytes are crucial for next-generation lithium batteries.
• Achieving ultrathin, strong, and conductive membranes (< tens of microns) is essential for high energy density but faces fabrication challenges.

Purpose of the Study:

• To develop an ideal ultrathin, strong, and conductive solid-state electrolyte membrane for advanced lithium batteries.
• To overcome limitations of traditional materials and fabrication techniques for high-performance battery components.

Main Methods:

• Fabrication of a 7.1 μm thick heterolayered Kevlar/covalent organic framework (COF) composite membrane.
• Utilized a bottom-up spin layer-by-layer assembly technology for precise structural and thickness control.
• Engineered strong chemical/mechanical interactions between cross-linked Kevlar and 2D-COF building blocks.

Main Results:

• Achieved a highly strong and Li+ conductive electrolyte membrane (1.62 × 10⁻⁴ S cm⁻¹ at 30 °C, 4.6 × 10⁻⁴ S cm⁻¹ at 70 °C).
• The membrane effectively prevented short-circuiting in solid-state batteries over 500 hours of cycling.
• Demonstrated significantly improved energy density in all-solid-state lithium batteries utilizing the novel membrane.

Conclusions:

• The developed heterolayered Kevlar/COF composite membrane represents a significant advancement in solid-state electrolyte technology.
• This membrane design enables the fabrication of safer and higher-energy-density solid-state lithium batteries.
• The bottom-up assembly approach offers precise control for creating advanced battery materials.