Composite polymer electrolyte containing ionic liquid and functionalized polyhedral oligomeric silsesquioxanes for...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Proton-exchange membranes (PEMs) are crucial for fuel cell technology.
• Achieving high anhydrous proton conductivity and mechanical stability remains a challenge.

Purpose of the Study:

• To develop a novel supported liquid membrane for anhydrous proton conduction.
• To enhance the thermal and mechanical properties of Nafion-based PEMs.

Main Methods:

• Layer-by-layer assembly of Nafion with sulfonated polyhedral oligomeric silsesquioxanes (S-POSS).
• Incorporation of ionic liquid (IL) 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI-BTSI) for anhydrous conductivity.
• Characterization of membrane properties including thermal stability, mechanical modulus, and proton conductivity.

Main Results:

• The hybrid membrane exhibited increased glass transition temperature and thermal stability with only 1% S-POSS.
• S-POSS improved proton conductivity, especially at low humidity, by promoting water uptake.
• The S-POSS/IL composite membrane showed significantly higher proton conductivity (5 mS/cm at 150°C) and improved high-temperature modulus compared to pristine Nafion and Nafion-IL membranes.

Conclusions:

• Multifunctional POSS and ILs can work synergistically to enhance PEM performance.
• The developed hybrid membranes offer a promising pathway for high-performance anhydrous PEMs in fuel cells.