Enhanced Fuel Cell Performance with Robust Pyridinium-Derivative-Functionalized SBS Triblock Copolymer Anion-Exchange...

Area of Science:

• Materials Science
• Polymer Chemistry
• Electrochemistry

Background:

• Anion-exchange membranes (AEMs) are crucial for alkaline fuel cells.
• Developing stable and high-performance AEMs remains a key challenge.
• Polystyrene-block-polybutadiene-block-polystyrene (SBS) offers a versatile platform for AEM development.

Purpose of the Study:

• To synthesize and characterize novel SBS-based AEMs functionalized with pyridinium derivatives (SBS-QA+py).
• To investigate the structure-property relationships governing membrane performance.
• To evaluate the potential of these AEMs for high-performance fuel cell applications.

Main Methods:

• Free-radical chlorination of polybutadiene segments in SBS using azobis(isobutyronitrile) (AIBN).
• Quaternization of chlorinated SBS via solution-casting to form SBS-QA+py AEMs.
• Characterization of ion-exchange capacity (IEC), water uptake (WU), ionic conductivity, and mechanical properties.
• Performance evaluation in H2/O2 fuel cells and chemical stability testing in alkaline media.

Main Results:

• SBS-QA+py membranes exhibited controlled IEC and WU, balancing hydration and mechanical integrity.
• Noncovalent stacking interactions between polystyrene and pyridinic segments enhanced membrane properties.
• The SBS-Qdpy2 AEM achieved a peak ionic conductivity of 101.23 mS cm-1 and a peak power density of 398.14 mW cm-2 at 80 °C.
• Excellent chemical durability was observed in 1 M NaOH over 30 days, demonstrating superior alkaline stability.

Conclusions:

• Optimized ion exchange and membrane morphology are critical for enhancing fuel cell performance.
• SBS-QA+py AEMs show superior performance and stability compared to previous SBS-based AEMs.
• These membranes are promising candidates for next-generation alkaline fuel cells.
• Further optimization of grafting, quaternization, and cross-linking can lead to stable AEMs with selective nanoionic channels for efficient anion diffusion.