A Korean research team has resolved a major durability issue in solid oxide electrolysis cells (SOECs), a technology that converts carbon dioxide (CO₂) into high-value chemical feedstocks.
Researchers at the Korea Research Institute of Chemical Technology (KRICT, President Seok-Min Shin), led by Drs. Min-Chul Kim, Ji Hoon Park, and Jin Hee Lee, developed a new electrolyte interface engineering technology for nickel-based SOECs. By redesigning the internal electrolyte interface structure, the team successfully prevented electrolyte layer cracking during high-temperature operation and achieved highly efficient conversion of CO₂ into carbon monoxide (CO).
SOECs are electrochemical devices that convert CO₂ into CO using electricity. The resulting CO serves as a key feedstock for syngas (CO + H₂), which can be utilized to produce sustainable aviation fuel (SAF), methanol, plastics, and industrial chemical materials.
A critical component of SOECs is the oxygen-ion-conducting electrolyte positioned between the electrodes. High-performance SOECs commonly employ two electrolyte materials together: yttria-stabilized zirconia (YSZ) and gadolinium-doped ceria (GDC). YSZ offers excellent durability but relatively low oxygen-ion conductivity, whereas GDC provides superior ionic conductivity but lower structural stability, enabling improved CO₂ conversion performance when combined.
However, the two materials exhibit different thermal expansion and shrinkage behaviors at high temperatures, causing interfacial delamination between the electrolyte layers during operation. This issue significantly degrades long-term durability and electrochemical performance. Although expensive deposition techniques such as physical vapor deposition (PVD) and pulsed laser deposition (PLD) have been explored to address this challenge, they remain costly and difficult to scale for large-area commercialization.
Instead of relying on high-cost equipment, the KRICT team employed a simple dip-coating process to form a composite intermediate layer composed of mixed YSZ and GDC powders, effectively suppressing interfacial delamination.
In simple terms, the researchers inserted a "buffer cushion layer" between the two different electrolyte materials. This composite intermediate layer absorbs thermal deformation differences, maintaining structural stability even under high-temperature conditions. During the process, the composite layer forms a new solid-solution structure that simultaneously enhances oxygen-ion transport and interfacial adhesion.
One of the key SOEC performance indicators is Faradaic efficiency, which represents how efficiently the supplied electricity is utilized to convert CO₂ into CO. Conventional SOECs typically exhibit Faradaic efficiencies of approximately 80–90%. The newly developed SOEC maintained 91% of its initial performance after 80 hours of continuous operation under a harsh 1.6 V condition, demonstrating exceptional durability along with world-class Faradaic efficiency.
The technology also significantly improved current density, a metric indicating how rapidly CO₂ can be processed per unit area. The current density increased from 0.59 to 2.14 A/cm², representing approximately a 3.6-fold improvement and achieving one of the highest performances reported for nickel-based SOECs.
In this study, the research team verified scalable fabrication conditions using coin-sized small cells and is currently expanding the technology to smartphone-sized flat-tubular cells. Because the process enables large-area manufacturing without expensive equipment, it is expected to facilitate future scale-up of electricity-driven industrial CO₂ utilization systems. However, further research on large-scale stack fabrication and renewable energy integration will still be required for commercialization.
KRICT President Seok-Min Shin stated, "This achievement simultaneously addresses the durability issue that has hindered both the commercialization and CO₂ conversion efficiency of solid oxide electrolysis cells."
The study was published as the back cover article in the March 2026 issue of Advanced Science (Impact Factor: 14.1). KRICT-UST student researcher Rustam Yuldashev participated as the first author, while Drs. Min-Chul Kim, Ji Hoon Park, and Jin Hee Lee served as corresponding authors.
