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Feb 07, 2025
Hydrogen production diaphragms are crucial components in water electrolysis hydrogen production technology. They are primarily used to separate hydrogen and oxygen gases while enabling ion transmission, ensuring the efficient and safe production of high - purity hydrogen. Depending on the electrolysis technology employed, the selection and performance requirements for diaphragm materials vary significantly. Here is an introduction to hydrogen production diaphragm materials:
1. Alkaline Electrolyzer (ALK) Diaphragm Materials
Material Types:
Asbestos (gradually phased out).
Polymer-based materials: such as polysulfone (PSF), polyphenylsulfone (PPS), and polyetheretherketone (PEEK).
Composite diaphragms: such as ZrO₂/PTFE.
Porous diaphragms: such as polytetrafluoroethylene (PTFE)-coated porous diaphragms.
Key Characteristics:
Resistance to strong alkalinity (pH 12-14) and high temperatures (80-90°C).
Microporous structure: pore size approximately 0.1-1μm, balancing ion conduction (OH⁻ migration) with gas barrier properties (H₂/O₂ separation).
Mechanical strength: Capable of withstanding the scouring of the electrolyte and resisting deformation caused by differential pressure.
2. PEM Electrolyzer Diaphragm - Proton Exchange Membrane (PEM)
Material Types:
Perfluorosulfonic acid diaphragms (PFSA): such as Nafion®, with sulfonic acid groups providing proton channels.
Modified diaphragms: enhanced mechanical/chemical stability by doping with inorganic materials (e.g., SiO₂, TiO₂).
Non-fluorinated diaphragms: such as sulfonated polyetheretherketone (SPEEK) or polybenzimidazole (PBI), which lower costs but may have durability concerns.
Key Characteristics:
High proton conductivity (>0.1 S/cm at 80°C).
Low gas permeability (H₂/O₂ crossover <1 mA/cm²).
High-pressure tolerance (>30 bar) and resistance to oxidative environments (high electrode potential on the anode side).
3. Solid Oxide Electrolyzer Cell (SOEC) Diaphragm Materials
Material Types:
Oxygen ion conductors: YSZ or GDC.
Proton-electron mixed conductors: such as BaZrO₃-based perovskite materials (high-temperature proton conductors).
Key Characteristics:
High-temperature operation (700-1000°C), requiring excellent thermal stability.
High ion conductivity (>0.01 S/cm) and low electronic leakage.
Dense structure: completely blocks gas crossover, allowing only ion transmission (O²⁻ or H⁺).
4. AEM Electrolyzer Diaphragm Materials - Anion Exchange Diaphragm
Material Types:
Quaternary ammonium polymer: such as polyphenylene oxide (PPO), polysulfone (PSF) grafted with quaternary ammonium groups.
Enhanced membranes: adding nanofibers (e.g., polyacrylonitrile) or inorganic fillers (e.g., SiO₂) to improve mechanical strength.
Key Characteristics:
Compatibility with non-precious metal catalysts (e.g., Ni, Fe).
Potential low cost (material price approximately 1/10 of Nafion®).
Market Applications:
Alkaline Electrolyzer: Still dominant, suitable for large-scale industrial hydrogen production.
PEM Electrolyzer: Rapid growth (efficiency >75%), suitable for coupling with fluctuating renewable energy sources.
SOEC/AEM: Currently in the demonstration phase, with the potential for breakthroughs in high - value applications, such as nuclear - based hydrogen production.
