DAEJEON — Researchers have developed a technology that produces hydrogen more efficiently and at lower cost.
The Korea Institute of Energy Research said on Sept. 17 that a team led by researchers Kang Kyoung-soo and Lee Hyun-jun at its Hydrogen Research Department had developed a water-electrolysis electrode that generates hydrogen more efficiently than costly precious-metal electrodes.
The electrode costs more than 99% less than precious-metal electrodes, which the institute said should significantly lower the unit cost of hydrogen production.
Water electrolysis is an environmentally friendly technology that splits water to obtain hydrogen. Among the available methods, alkaline water electrolysis requires less capital spending on equipment, making it well suited to large-scale hydrogen production.
Its drawback is a slower hydrogen production rate than other electrolysis methods. In an alkaline environment, the reaction that splits water and produces hydrogen proceeds at least 100 times more slowly than in an acidic environment. Precious-metal electrodes such as platinum and ruthenium can speed up the reaction, but their high cost has made the shift to mass production difficult.
To replace precious-metal electrodes, the team designed a new "heterostructured electrode" that places nickel oxide, which promotes the splitting of water, alongside a nickel-cobalt alloy that favors the hydrogen evolution reaction on a single electrode surface.
The nickel oxide accelerates the water-splitting step, the slowest stage in alkaline electrolysis, while the nickel-cobalt alloy enhances the hydrogen evolution reaction, raising the overall reaction rate.
Under identical conditions, the electrode triggered the hydrogen evolution reaction at only 40% of the voltage required by a commercial platinum electrode. That places it among the best-performing non-precious-metal alkaline electrodes reported in the past three years.
The team also confirmed the electrode's potential for industrial use beyond the laboratory. A unit cell measuring 8.7 centimeters in diameter that used the electrode recorded a voltage 11% lower than a nickel electrode without the new material. Durability did not decline after more than 600 cycles of repeated operation and shutdown, demonstrating that the electrode can run stably even when paired with renewable energy sources that supply power unevenly.
Kang, who led the research, said the work "shows that world-class alkaline water-electrolysis electrodes can be made without expensive precious metals." Lee said, "We plan to scale this up to an area of more than 5,000 square centimeters and apply it to megawatt-class alkaline water electrolysis."
The findings were published online in Advanced Science, an international academic journal.
