Anisotropically Wettable Porous Transport Layers for Gas Management in Water Electrolyzers.

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Porous transport layers (PTLs) are critical for efficient water electrolysis but often overlooked.
• Effective mass transport in PTLs is essential for long-term, high-current operation.
• Gas bubble accumulation in PTLs hinders catalyst activity and electrolyte supply in anion exchange membrane water electrolyzers (AEMWEs).

Purpose of the Study:

• To introduce a novel PTL with anisotropic wettability (AW-PTL) for enhanced AEMWE efficiency.
• To investigate the impact of directional mass transport on AEMWE performance.
• To provide a scalable and adaptable solution for improving water electrolysis.

Main Methods:

• Fabrication of AW-PTL by spray-coating polytetrafluoroethylene onto hydrophilic Ni foam.
• Modification of PTLs to achieve anisotropic wettability for directional liquid and gas transport.
• Testing of AW-PTL in anion exchange membrane water electrolyzers (AEMWEs).

Main Results:

• The AW-PTL design significantly improved AEMWE efficiency.
• Directional transport facilitated gas bubble removal and maintained electrolyte supply.
• The method demonstrated scalability to large-area (225 cm²) and short-stack AEMWEs.
• The approach is applicable to various PTL types and water electrolyzer configurations.

Conclusions:

• Anisotropic wettability in PTLs is a viable strategy to enhance water electrolysis.
• The developed AW-PTL offers a practical solution for improving AEMWE performance and scalability.
• This work paves the way for more efficient and robust water electrolyzer technologies.