Polystyrene-Based Hydroxide-Ion-Conducting Ionomer: Binder Characteristics and Performance in Anion-Exchange Membrane...

Area of Science:

• Polymer Chemistry
• Electrochemistry
• Materials Science

Background:

• Anion-exchange membrane fuel cells (AEMFCs) are promising for clean energy conversion.
• Effective ionomers are crucial for catalyst binder performance in AEMFCs.
• Developing novel ionomers with tailored properties is essential for advancing AEMFC technology.

Purpose of the Study:

• To synthesize and characterize novel hydroxide-ion-conducting ionomers for AEMFC electrode binders.
• To investigate the structure-property relationships of these ionomers.
• To evaluate the performance of AEMFCs utilizing the developed ionomers.

Main Methods:

• Radical polymerization of styrene to create polystyrene backbones of varying molecular weights.
• Grafting bromo-alkyl chains via Friedel-Crafts acylation and subsequent quaternization.
• Structural analysis including molecular weight determination and ion exchange capacity measurement.
• Fabrication and testing of AEMFCs with the synthesized ionomers.

Main Results:

• Polystyrene backbone molecular weights ranged from 10,000 to 63,000 g mol⁻¹.
• Ion exchange capacity of the quaternary-ammonium ionomers was between 1.44 and 1.74 mmol g⁻¹.
• AEMFCs achieved a maximum power density of 407 mW cm⁻².
• The developed ionomers demonstrated superior durability compared to a commercial reference.

Conclusions:

• The developed ionomers are suitable for high-performance AEMFCs.
• The synthesis approach enables the fabrication of next-generation electrode ionomers.
• This work contributes to the advancement of AEMFC technology for practical applications.