Thermally Stable Al₂O₃/PTFE Composite Separator for High-Safety Lithium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Growing demand for carbon neutrality and safer energy storage necessitates advanced lithium-ion battery (LIB) separators.
• Conventional polyolefin separators exhibit poor thermal stability and electrolyte wettability, compromising LIB safety and performance.

Purpose of the Study:

• To develop and evaluate a novel nonwoven polytetrafluoroethylene (PTFE) nanofiber (NF) separator incorporating aluminum oxide (Al2O3) particles.
• To enhance the thermal stability, porosity, and electrolyte wettability of LIB separators for improved safety and electrochemical performance.

Main Methods:

• Fabrication of a binder-free nonwoven PTFE NF separator using emulsion electrospinning with Al2O3 particles.
• Plasma surface modification of the Al2O3-PTFE NF separator to improve electrolyte wettability.
• Characterization of separator properties including porosity, thermal stability, and electrolyte wettability.
• Evaluation of electrochemical performance, including ionic conductivity, in LIB cells.

Main Results:

• The fabricated Al2O3-PTFE NF separator exhibited superior porosity, thermal stability, and electrolyte wettability compared to conventional polyolefin separators.
• Plasma surface modification significantly enhanced electrolyte wettability, leading to improved ionic conductivity (2.79 mS cm-1).
• The modified separator demonstrated boosted overall electrochemical performance in LIB cells.

Conclusions:

• The developed Al2O3-PTFE NF separator is a promising candidate for safer and more efficient LIBs.
• The enhanced properties address critical challenges in LIB safety and performance, paving the way for advanced energy storage solutions.