A stainless steel breakthrough from the University of Hong Kong (HKU) could help solve one of the biggest problems facing green hydrogen: how to build electrolysers that are tough enough for seawater, yet cheap enough for large scale clean energy.
Led by Professor Mingxin Huang in HKU’s Department of Mechanical Engineering, the team developed a special stainless steel for hydrogen production (SS-H2).
The material resists corrosion under conditions that normally push stainless steel past its limits, making it a promising candidate for producing hydrogen from seawater and other harsh electrolyser environments.
The discovery, reported in Materials Today, builds on Huang’s long running “Super Steel” Project.
The same research programme previously produced anti-COVID-19 stainless steel in 2021, along with ultra-strong and ultra-tough super steel in 2017 and 2020.
A cheaper path toward green hydrogen
Green hydrogen is made by using electricity, ideally from renewable sources, to split water into hydrogen and oxygen.
Seawater is
Recent reviews of direct seawater electrolysis continue to highlight the same core challenge.
The technology could provide a more sustainable route to hydrogen, but corrosion, chlorine related side reactions, catalyst degradation, precipitates, and limited long-term durability remain major obstacles to commercial use.
That is where SS-H2 could matter. In a saltwater electrolyser, the HKU team found that the new steel can perform comparably to the titanium-based structural materials used in current industrial practice for hydrogen production from desalted seawater or acid.
The difference is cost. Titanium parts coated with precious metals such as gold or platinum are expensive, while stainless steel is far more economical.
For a 10MW PEM electrolysis tank system, the total cost at the time of the HKU report was estimated at about
According to the team’s estimate, replacing those costly structural materials with SS-H2 could reduce the cost of structural material by about 40 times.
A six-year push from surprise to application
The path from the first observation to publication was not quick. The team spent nearly six years moving from the initial discovery of the unusual stainless steel to the deeper scientific explanation, then toward publication and potential industrial use.
“Different from the current corrosion community, which mainly focuses on the resistance at natural potentials, we specialise in developing high-potential-resistant alloys.
“Our strategy overcame the fundamental limitation of conventional stainless steel and established a paradigm for alloy development applicable at high potentials. This breakthrough is exciting and brings new applications,” Professor Huang said.
The work has also moved beyond the laboratory. The research achievements have been submitted for patents
The team also reported that tons of SS-H2 based wire had been produced with a factory in Mainland China.
“From experimental materials to real products, such as meshes and foams, for water electrolysers, there are still challenging tasks at hand,” added Professor Huang.
“Currently, we have made a big step toward industrialisation. Tons of SS-H2-based wire has been produced in collaboration with a factory from the Mainland.
“We are moving forward in applying the more economical SS-H2 in hydrogen production from renewable source.”
Why the timing still matters
Although the SS-H2 study was published in 2023, its core problem has only become more relevant. Newer seawater electrolysis research continues to focus on the same bottlenecks: corrosion resistant materials, long lasting electrodes, chlorine suppression, and system designs that can survive real seawater rather than ideal laboratory
A 2025 Nature Reviews Materials review described direct seawater electrolysis as promising but still held back by corrosion, side reactions, metal precipitates, and limited lifetime.
The field is still searching for materials that can survive the punishing mix of saltwater chemistry, high voltage, and industrial operating demands.
SS-H2 stands out because it attacks the problem not only with a coating or catalyst, but with a new alloy design strategy that changes how stainless steel protects itself.
A steel breakthrough with clean energy potential
SS-H2 is not yet a plug-and-play solution for the hydrogen economy. The team has acknowledged that turning experimental materials into real electrolyser products, including meshes and foams, still involves difficult engineering work.
Even so, the promise is there. A stainless steel that can withstand high-voltage seawater conditions while replacing expensive titanium-based components could make hydrogen production cheaper, more scalable, and easier to pair with renewable energy.
For a field where cost and durability often decide whether a technology can leave the lab, a steel that builds its own second shield could become a practical step towards cleaner hydrogen at industrial scale.
