PP-PE-PP Trilayer Membrane

PP/PE/PP trilayer microporous membranes are widely used as battery separator films in secondary lithium batteries. The separator electrically isolates the cathode and anode while allowing Li⁺ ion transport through a controlled pore network filled with electrolyte. The trilayer architecture combines PP outer layers (mechanical strength and dimensional stability) with a PE inner layer designed for thermal shutdown behaviour in abuse conditions.

Working mechanism

During normal operation, electrolyte wets the micropores and enables ionic conduction. If the cell temperature rises toward the PE melting/softening region, the PE inner layer closes pores (“shutdown”), sharply reducing ion flow and helping limit runaway reactions, while the PP layers help maintain structural integrity.

Key features and typical specifications (20 µm grade)

• Thickness: 20 µm
• Gurley (JIS): 530 s (air permeability/tortuosity indicator)
• Porosity: ~39% (supports electrolyte uptake)
• Thermal shrinkage (TD): 0% @ 90 °C / 1 h; 0% @ 105 °C / 1 h
• Tensile strength: TD 165 (min 115) kg/cm²; MD 2050 (min 1500) kg/cm²
• Puncture strength: 360 gf
• Chemical resistance: strong resistance to acids, bases, and many battery electrolyte environments
  
  

Compatibility and applications

Suitable for coin, cylindrical, prismatic, and pouch cell R&D assembly using common carbonate electrolytes and standard electrode chemistries (graphite, silicon-blends, NMC, LFP, etc.). Ideal for:

• High-rate cycling and long-life testing
• Safety-focused separator screening
• Lab-scale cell prototyping and benchmarking
  
  

Why source via ScienceGears

ScienceGears supports separator selection alongside battery cyclers, potentiostats, and cell assembly consumables to help researchers build reliable, reproducible battery-test workflows in Australia and New Zealand.