Alkaline Stable and Mechanically Robust Interpenetrating Polymer Network Type Anion Exchange Membrane for...

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Anion exchange membranes (AEMs) are crucial for anion exchange membrane water electrolyzers (AEMWEs) but suffer from degradation in alkaline environments.
• Improving AEM durability is essential for efficient and long-lasting hydrogen production.

Purpose of the Study:

• To develop and characterize interpenetrating polymer network anion exchange membranes (IPN-AEMs) with enhanced alkaline stability.
• To evaluate the performance of these IPN-AEMs in alkaline and seawater electrolysis.

Main Methods:

• Fabrication of IPN-AEMs with varying thicknesses (110, 80, and 40 µm).
• Physicochemical property characterization (water uptake, ion exchange capacity, ionic conductivity).
• Alkaline stability testing (5 m KOH, 80 °C, 90 days) and degradation pathway analysis (FT-IR, computational analysis).
• Electrolysis performance evaluation in alkaline (1 m KOH, 80 °C) and seawater conditions.

Main Results:

• IPN-AEM-40 exhibited superior properties: 33% water uptake, 1.3 meq g⁻¹ ion exchange capacity, and 5.5 × 10⁻² S cm⁻¹ ionic conductivity.
• IPN-AEM-40 retained 75% ionic conductivity after 90 days in 5 m KOH at 80 °C, with nucleophilic substitution as the main degradation pathway.
• Electrolysis tests showed high performance: 850 mA cm⁻² at 2 V in 1 m KOH and 600 mA cm⁻² in seawater at 80 °C.

Conclusions:

• The developed IPN-AEM-40 demonstrates excellent alkaline stability and physicochemical properties.
• These findings highlight the potential of IPN-AEM-40 for durable and high-performance hydrogen generation using AEMWEs, including in seawater electrolysis.