Sulfonated-PPS/LDH Composite Membrane With Hydrogen Bond Network for High-Performance Alkaline Water Electrolysis

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Composite membranes are crucial for alkaline water electrolysis (AWE) in green hydrogen production.
• Current membranes face challenges with low conductivity and insufficient long-term stability.
• Developing advanced membranes is key to improving AWE efficiency and durability.

Purpose of the Study:

• To develop a novel composite membrane for highly efficient alkaline water electrolysis.
• To enhance ion transport and membrane stability through a hydrogen bond network.
• To compare the performance of the new membrane against commercial standards.

Main Methods:

• Fabrication of a sulfonated polyphenylene sulfide (sPPS) and NiFe-layered double hydroxide (LDH) composite membrane via a sulfonation-casting strategy.
• Characterization of membrane properties including thermal stability, mechanical strength, hydrophilicity, bubble point pressure, and area resistance.
• Utilizing molecular dynamics simulations to understand the role of LDH in ion transport.
• Testing the membrane's performance in an alkaline water electrolyzer.

Main Results:

• The sPPS/LDH composite membrane demonstrated superior thermal stability, mechanical strength, hydrophilicity, high bubble point pressure, and lower area resistance compared to commercial ZIRFON 500.
• Molecular dynamics simulations indicated that the presence of LDH promotes hydrogen bond formation, accelerating ion transport.
• The optimized membrane achieved a current density of 936 mA cm⁻² at 1.9 V in 30 wt.% KOH at 80°C.
• Stable operation exceeding 500 hours at 500 mA cm⁻² was maintained.

Conclusions:

• The developed sPPS/LDH composite membrane offers a promising solution for efficient and stable alkaline water electrolysis.
• The formation of a hydrogen bond network within the composite membrane is critical for enhancing ion conductivity and overall performance.
• This approach provides a pathway for designing next-generation membranes for green hydrogen production.