Why PPSU is a Superior Material for Hydrogen Electrolyzer Pole Frames

Introduction

As global interest in green hydrogen continues to surge, alkaline water electrolysis (AWE) remains a mainstream and cost-effective method for industrial-scale hydrogen production. In this system, the pole frame (also known as the electrolyzer frame or bipolar plate frame) plays a crucial structural and functional role. It supports the electrode plates, channels gas and liquid flows, and ensures electrical insulation and sealing under high-pressure alkaline conditions.

Traditionally, these frames are manufactured from carbon steel due to its strength and pressure resistance. However, with the increasing demands for durability, safety, and cost-efficiency, high-performance thermoplastics such as PPSU (Polyphenylsulfone) have emerged as a promising alternative.

Structure and Function of Pole Frames in Alkaline Electrolyzers

In a typical AWE stack, each electrode unit consists of a main electrode plate and an outer pole frame. The pole frame is designed with multiple gas channels at the top and a set of liquid channels at the bottom to enable controlled injection and zoned circulation of the alkaline electrolyte.

Key functional zones of the pole frame include:

• Tongue Plate Area: Welded connection with the main electrode plate
• Sealing Line Zone: A sawtooth cross-section along the outer edge for leak-proof sealing
• Overlap Zone: Where the diaphragm and gasket layers align

These structures must maintain precise geometries under prolonged exposure to highly corrosive, high-temperature, and high-pressure conditions, making the material selection critical.

Challenges with Traditional Metal Pole Frames

Carbon steel has long been favored for its rigidity and pressure resistance. However, it presents several drawbacks when used in harsh alkaline environments:

• Corrosion Susceptibility: High-temperature, high-concentration alkaline electrolytes can corrode steel frames over time, leading to performance loss and higher maintenance costs.
• Weight and Handling: The heavy weight of steel increases transportation, assembly, and stack design complexity.
• Machining and Processing Cost: Metal machining requires multiple steps, increases production time, and limits design flexibility for complex fluid channels or sealing patterns.
• Electrical Conductivity: In some systems, electrical insulation is critical to avoid short-circuits. Metal frames often require additional insulating layers, adding to the complexity.

PPSU: A High-Performance Alternative for Electrolyzer Frames

Polyphenylsulfone (PPSU), an amorphous, high-performance thermoplastic, offers a comprehensive solution to the challenges of metal frames. It excels in harsh chemical environments and delivers significant processing and functional advantages.

1. Excellent Chemical Resistance

PPSU exhibits outstanding resistance to strong alkalis, acids, and oxidizing agents. In electrolytic environments with elevated KOH or NaOH concentrations, PPSU maintains structural integrity without swelling, cracking, or leaching, unlike conventional plastics or corroding metals.

2. High Heat Resistance

With a heat deflection temperature (HDT/A) of 196 °C and relative temperature index (RTI) up to 180 °C, PPSU performs reliably in electrolysis systems that operate under elevated thermal loads.

3. Mechanical Strength and Toughness

PPSU offers a high tensile strength (~70 MPa) and excellent impact resistance (~690 J/m), allowing the frame to withstand electrolyte pressure, stack compression, and vibration without deformation or fracture.

4. Electrical Insulation

As a naturally insulating polymer, PPSU reduces the risk of electric leakage or short circuits in modular stack designs—eliminating the need for secondary insulation treatments.

5. Lightweight and Moldable

The lower density (~1.29 g/cm³) compared to metal dramatically reduces system weight. PPSU supports injection molding, enabling mass production of complex geometries (e.g., gas/liquid channels, tongue structures) with high dimensional precision and excellent repeatability.

Application Example: PPSU in Pole Frame Design

In redesigned electrolyzer stacks using PPSU pole frames:

• The tongue area can be seamlessly integrated with the diaphragm and gasket alignment zone.
• Precision-molded gas and liquid channels reduce pressure drop and improve flow distribution.
• The sealing zones can incorporate sawtooth or labyrinth structures directly during molding, improving airtightness.
• The non-conductive, non-corrosive nature of PPSU enhances stack life and simplifies the system architecture.

Why Choose Tuntun Plastic for PPSU Materials?

Shengwen New Materials is a trusted supplier of high-performance PPSU materials specifically formulated for high-temperature, chemical-resistant applications like electrolyzer pole frames.

Key Product Highlights:

• Grades Available: F1150, F1250, F1350, M1150 (with tailored melt flow rates)
• Heat Resistance: HDT/A up to 196 °C
• Tensile Strength: 70 MPa
• Impact Strength: Up to 68 kJ/m² (notched)
• Certifications: Compliant with ISO10993, UL94 V-0, RoHS, REACH, and NSF standards
• Customization: Color matching, glass fiber reinforcement, and semi-finished rod/sheet formats available
• Fast Sampling: 3kg samples within 5 working days; bulk orders within 15–30 working days

Conclusion

Replacing traditional carbon steel with PPSU pole frames in hydrogen electrolyzers represents a strategic shift toward more durable, corrosion-resistant, lightweight, and cost-effective system designs. PPSU not only withstands harsh operating environments but also enables advanced component integration through precision molding.

By partnering with Shengwen New Materials, you gain access to reliable, engineering-grade PPSU backed by technical expertise and flexible customization—empowering your electrolyzer innovation for the hydrogen economy of the future.