KIER's non-noble-metal electrode slashes green hydrogen production costs, overcoming a key bottleneck

■ A research team led by Dr. Kyung-Soo Kang and Dr. Hyun-Jun Lee from the Hydrogen Energy Research Division of the Korea Institute of Energy Research (KIER) has developed novel Ni/Co-based heterostructure water electrolysis electrodes that deliver superior hydrogen production efficiency compared to conventional noble-metal electrodes. The developed electrodes have achieved a 99% material cost reduction over noble-metal electrodes, contributing to a significant reduction in hydrogen production costs.

□ Water electrolysis is an eco-friendly technology that produces hydrogen by splitting water using electricity. In particular, alkaline electrolysis is ideal for large-scale hydrogen production owing to its relatively low installation and equipment costs.

□ However, its hydrogen production rate remains lower than those of alternative technologies, as the water-splitting kinetics under alkaline conditions are over 100 times slower than in acidic environments. Although noble-metal catalysts such as platinum and ruthenium significantly boost reaction rates, their high raw material prices pose a major bottleneck for mass production.

■ Against this backdrop, the KIER research team designed a novel heterostructure electrode that integrates Ni oxide - which accelerates water dissociation - and a Ni-Co alloy - which facilitates hydrogen production - on a single electrode surface.

□ Specifically, Ni oxide effectively promotes water dissociation, the rate-determining step in alkaline water electrolysis. Simultaneously, the Ni-Co alloy enhances hydrogen evolution, thereby accelerating the overall reaction kinetics.

□ The developed electrode delivers equivalent hydrogen production rates at roughly 40% of the overpotential required by conventional platinum electrodes – demonstrating top-tier performance among non-noble-metal alkaline electrodes reported over the past three years.

□ Furthermore, the KIER research team demonstrated the commercial viability of the technology beyond the laboratory scale. A unit cell with an 8.7-cm diameter equipped with the developed electrode achieved cell voltage 11% lower than that of a conventional nickel-electrode-based cell. Moreover, its performance remained stable even after 600 repeated start-stop cycles, validating its operational durability when coupled with intermittent renewable energy sources.

■ Dr. Kyung-Soo Kang, the lead researcher of the study at KIER, said, "This research proves that non-noble-metal electrodes can achieve world-class performance and durability in alkaline water electrolysis. This technology will pave the way for the domestic sourcing of essential materials for alkaline electrolysis, which has relied significantly on imports, ultimately contributing to lower green hydrogen production costs."

□ Adding to this, Dr. Hyun-Jun Lee, co-lead of the project, emphasized, "We have successfully verified the feasibility of scaling up this technology by fabricating large-scale electrodes with a diameter of 40 cm, and we are currently optimizing the process for commercial mass production. Going forward, our research will focus on expanding the electrode area to 5,000 cm² for deployment in megawatt-scale alkaline electrolysis systems."

□ This research was supported by the National Hydrogen Hub Laboratory Project funded by the Ministry of Science and ICT, with key findings published online in Advanced Science(IF 14.1, ranked in the top 10% of JCR).