Highly Stable Engineered Homogeneous Bipolar Membranes for Efficacious Water Electrolysis for Hydrogen Generation.

Area of Science:

• Electrochemistry
• Materials Science

Background:

• Bipolar membrane (BPM) water electrolysis offers high-efficiency hydrogen production by enabling independent pH control at electrodes.
• Conventional proton exchange membrane (PEM) and anion exchange membrane (AEM) electrolyzers face limitations that BPMs overcome.
• In BPMs, faster proton (H+) transport than hydroxide (OH-) migration requires thin AEMs to reduce resistance and boost membrane electrode assembly (MEA) efficiency.

Purpose of the Study:

• To investigate the effect of varying AEM thickness (10, 20, 30 µm) on BPM performance for hydrogen production.
• To evaluate different electrolyte conditions using an optimized BPM-A10/C30 MEA.
• To identify optimal configurations for efficient and stable hydrogen generation.

Main Methods:

• Fabrication and testing of BPM-based membrane electrode assemblies (MEAs) with varying AEM thicknesses.
• Electrochemical characterization including current density and cell resistance measurements.
• Hydrogen generation experiments using three electrolyte combinations with a fixed anolyte (1 m KOH) and varied catholyte (0.5 m H2SO4, deionized water, seawater).

Main Results:

• The BPM-A10/C30 MEA (10 µm AEM, 30 µm CEM) demonstrated superior electrochemical performance.
• The combination of 0.5 m H2SO4 catholyte and 1 m KOH anolyte yielded the best results.
• This configuration achieved a maximum current density of 1000 mA cm⁻² at 1.9 V with the lowest cell resistance (0.09 Ω cm²).

Conclusions:

• Optimizing AEM thickness is crucial for enhancing ion transport and MEA stability in BPM water electrolysis.
• The study highlights the potential of BPM technology for cost-effective and scalable hydrogen production.
• Specific electrolyte combinations can further improve the efficiency of BPM-based hydrogen generation systems.