Leak-proof gasket with functionalized boron nitride nanoflakes enhances performance and durability

A research team in South Korea has developed a novel gasket technology that enhances both the safety and efficiency of polymer electrolyte membrane fuel cells (PEMFCs) and water electrolyzers (PEMWEs, AEMWEs)—core devices for hydrogen production and utilization—by simultaneously improving mechanical strength and gas-tight sealing.

Dr. Keun-Hwan Oh and his colleagues at the Korea Research Institute of Chemical Technology (KRICT) have successfully applied functionalized two-dimensional boron nitride nanoflakes (BNNFs) to silicone and ethylene-propylene-diene monomer (EPDM)-based sealing gaskets. The newly developed nanocomposite gasket demonstrates excellent mechanical robustness, hydrogen-barrier capability, and chemical and thermal stability.

In hydrogen-energy systems, gaskets play a vital role in sealing reactant gases and preventing hydrogen leakage within the stack. A decline in gasket performance can reduce system efficiency and even cause severe safety hazards.

While fluoroelastomer-based gaskets offer strong durability, their high cost and PFAS-related environmental restrictions limit widespread use. In contrast, EPDM and silicone materials are more affordable and processable but suffer from poor hydrogen impermeability and chemical resistance.

To overcome these drawbacks, the KRICT team functionalized boron nitride nanoflakes using 1-pyrenemethyl methacrylate (1-PMA), enabling C–C coupling between the nanofiller and polymer chains. This strategy formed a densely crosslinked network that maximizes the “maze-effect” for hydrogen diffusion and maintains structural stability even under harsh operating conditions.

Remarkably, incorporating only 0.5 wt % of functionalized BNNFs led to substantial improvements:

· EPDM composite: +32.1 % in Young’s modulus, −55.7 % in H₂ permeability

· Silicone composite: +96.6 % in Young’s modulus, −42.7 % in H₂ permeability

In long-term chemical-durability tests (225 hours) under acidic and alkaline conditions, the EPDM nanocomposite showed only 6.6 % and 3.8 % weight loss respectively, while the silicone composite exhibited minimal degradation of 0.2 % and 2.1 %.

Cell-performance evaluation confirmed that both nanocomposite gaskets delivered equivalent or superior current densities compared with commercial gaskets, ensuring uniform internal pressure distribution and reduced contact resistance between electrodes.

This breakthrough goes beyond mechanical reinforcement—it improves gas-barrier, chemical-resistance, and electrochemical performance simultaneously, offering a viable non-fluorinated alternative for hydrogen energy systems.

The technology is expected to accelerate early commercialization for hydrogen-fuel-cell vehicles, power-generation stacks, and large-scale water-electrolysis systems.

Dr. Oh stated, “This study establishes the foundation for domestic production of high-performance silicone-based gaskets that were previously dependent on imports.”

KRICT President Dr. Young-Kuk Lee added, “By developing PFAS-free, high-durability sealing materials, we can achieve both environmental compliance and enhanced safety.”

This research was published in Advanced Composites and Hybrid Materials (Impact Factor 21.8) in October 2025, under the title

“Enhanced Performance and Durability of Sealing Gasket for Polymer Electrolyte Membrane Fuel Cells and Water Electrolyzer by C–C Coupling of Functionalized 2D Boron Nitride Nanoflakes.”

The study was jointly led by Dr. Keun-Hwan Oh (KRICT) and Professor Hong Suk Kang (Inha University), with Won-Jong Choi (KRICT) as first author.

###

KRICT is a non-profit research institute funded by the Korean government. Since its foundation in 1976, KRICT has played a leading role in advancing national chemical technologies in the fields of chemistry, material science, environmental science, and chemical engineering. Now, KRICT is moving forward to become a globally leading research institute tackling the most challenging issues in the field of Chemistry and Engineering and will continue to fulfill its role in developing chemical technologies that benefit the entire world and contribute to maintaining a healthy planet. More detailed information on KRICT can be found at https://www.krict.re.kr/eng/

The study was supported by KRICT’s Basic Research Program and the Technology Independence for Green Hydrogen Project funded by the Ministry of Science and ICT through the National Research Foundation of Korea.