A Novel Material for High-Performance Li-O₂ Battery Separator: Polyetherketone Nanofiber Membrane

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Separator properties critically influence lithium-based battery efficiency, stability, and safety.
• Polyetherketone (PEK) possesses desirable mechanical, chemical, and thermal stability for battery separators.
• PEK's poor processability due to low solubility hinders nanoscale applications.

Purpose of the Study:

• To overcome the processing limitations of PEK for advanced battery separator applications.
• To develop a novel PEK-based nanofiber membrane with improved properties.
• To evaluate the performance of the fabricated PEK membrane in lithium-oxygen batteries.

Main Methods:

• Synthesized a soluble precursor polymer by introducing a protecting group into the PEK monomer.
• Fabricated the precursor into a nanofiber membrane.
• Converted the nanofiber membrane into PEK nanofiber membrane via acid treatment (chemical-induced crystallization).

Main Results:

• The chemical-induced crystallization method yielded a PEK nanofiber membrane with superior chemical, thermal, and mechanical stability.
• Lithium-oxygen batteries utilizing the fabricated PEK membrane demonstrated high cycling stability (194 cycles at 200 mA g⁻¹ and 500 mAh g⁻¹).

Conclusions:

• This work successfully addresses PEK's processability challenges for nanoscale manufacturing.
• The developed PEK nanofiber membrane presents a promising material for advanced battery separators.
• The study broadens the application scope of PEK in energy storage devices.