A domestic research team identified the core cause of the "electrode freeze-cracking" problem that degrades the performance and durability of Hydrogen Fuel Cells in winter and succeeded in solving it with a simple heat-treatment process.
The National Research Foundation of Korea (NRF) said on the 5th that a joint research team of Professor Pyo Jae-bum of Kongju National University, Professor Kim Taek-su of Korea Advanced Institute of Science and Technology (KAIST), and Senior Researcher Kim Ji-hoon of the Agency for Defense Development (ADD) identified the cause of electrode freeze-cracking and solved it through a heat-treatment process at 190 degrees for 10 minutes. An ionomer is a polymer that absorbs water to conduct charges such as hydrogen ions while simultaneously binding and supporting particles.
Hydrogen Fuel Cells and water electrolysis devices, which split water into electricity, are considered core future clean energy technologies. However, in severe cold during winter, residual water inside the electrode freezes and creates cracks, which lowers the device's performance and lifespan.
Previous studies have viewed the cause of such damage as pressure created when water trapped in microscopic pores in the electrode freezes. Accordingly, until now the approach has relied on raising the temperature with heaters or external auxiliary devices.
The researchers found that even if an electrode has fewer nanopores and superior initial mechanical performance, a higher ionomer content makes it more vulnerable to freeze-cracking. They identified that the main culprit is not the nanopores but the "ionomer agglomerates," which soak up water like a sponge.
To solve the problem, the research team applied a heat-treatment process at 190 degrees for 10 minutes. In this process, the ionomer's nanostructure was compactly rearranged to control the very space where water can remain, and as a result, they secured breakthrough durability that maintained more than 90% of the initial mechanical performance even at a frigid minus 20 degrees.
Professor Pyo Jae-bum said, "This achievement overturns the conventional wisdom about the cause of electrode freeze-cracking and presents a new solution by pinpointing its fundamental cause," and added, "Through this, it is expected to be widely applicable not only to improving stable winter startups for hydrogen vehicles and the reliability of electrolysis plants in frigid regions, but also to enhancing low-temperature stability in various future energy storage devices that use ionomers, such as next-generation batteries and supercapacitors."
The research team plans to develop the technology into one that can be applied to large-scale systems after verification through long-term repeated freezing and thawing tests and in actual power generation system environments.
The results of this research were published in the international journal in the fields of energy and materials science, "Carbon Energy," on Oct. 31 (local time).
References
Carbon Energy (2025), DOI: https://doi.org/10.1002/cey2.70098