Flame-retardant polyimide-based quasi-solid polymer electrolyte enabling high-performance and safe lithium-ion...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Flammable liquid electrolytes in lithium-ion batteries (LIBs) pose safety risks.
• Quasi-solid polymer electrolytes (QPEs) offer a safer alternative but require balancing safety and performance.
• Industrialization of QPEs is hindered by the need for superior safety and electrochemical characteristics.

Purpose of the Study:

• To develop a flame-retardant and electrochemically high-performance QPE for enhanced LIB safety.
• To create a QPE that simultaneously possesses superior safety characteristics and excellent electrochemical performance.
• To address the industrialization challenges of QPEs by improving their safety and performance metrics.

Main Methods:

• Development of a flame-retardant Poly(vinylidene fluoride-co-hexafluoropropylene)-Polyimide (PFP-PI) QPE.
• Characterization of ionic conductivity at room temperature.
• Assembly and testing of LIBs using the developed QPE, including cycling performance and mechanical property evaluation.
• Assessment of flame retardancy and smoke emission during thermal events.

Main Results:

• The PFP-PI QPE achieved an ionic conductivity of 1.02 × 10^-3 S/cm at room temperature.
• Batteries demonstrated stable cycling, retaining 88.49% capacity after 900 cycles at 1 C.
• The electrolyte exhibited robust mechanical properties, suppressed lithium dendrite growth, and reduced smoke emission without additional flame retardants.
• Flexible pouch cells maintained electrical integrity upon bending and cutting.

Conclusions:

• The developed PFP-PI QPE offers a promising solution for safer LIBs by combining flame retardancy with high electrochemical performance.
• The material effectively suppresses dendrite growth and enhances thermal safety, reducing hazard risks.
• The QPE's mechanical flexibility and stability make it suitable for advanced battery applications, including flexible devices.