South Korean researchers have developed a Hybrid-Solid Electrolysis Cell (Hybrid-SOEC) system with the highest reported electrochemical performance in hydrogen production.
This breakthrough was performed by Professor Guntae Kim from the School of Energy and Chemical Engineering at UNIST in collaboration with Professor Tak-Hyoung Lim of Korea Institute of Energy Research (KIER) and Professor Jeeyoung Shin of Sookmyung Women’s University.
According to the UNIST team, the proposed system offers a cost-effective and highly-efficient hydrogen production, as it shows excellent performance compared with other water-electrolysis systems.
A solid oxide electrolyzer cell (SOEC) consists of two electrodes and an electrolyte that are all in solid-state. They are strongly desired as novel candidates for the hydrogen production, as they require no need to replenish lost electrolytes, while eliminating the corrosion problems.
Moreover, SOECs operate at relatively high temperatures (700-1000 °C), which helps to offer reduced electrical energy consumption.
UNIST’s Hybrid-SOEC is based on the mixed ionic conducting electrolyte, allowing water electrolysis to be occurred at both hydrogen and air electrodes. The existing SOEC electrolytes allows the transport of either only one of the hydrogen or oxygen ions to the other electrode.
For the cases involving SOEC electrolytes that transport oxygen ions, water electrolysis occurs at the anode and this results in the production of hydrogen.
In contrast, the SOEC electrolytes that transport hydrogen ions cause water electrolysis to occur at the cathode and this results in the production of oxygen. Here, hydrogen travels through the electrolyte to the anode.
According to the researchers, the proposed system demands less electricity for hydrogen production, while exhibiting outstanding electrochemical performance with stability.
Moreover, the Hybrid SOEC exhibits no observable degradation in performance for more than 60 hours of continuous operation, implying a robust system for hydrogen production.
According to the team, the corresponding yields of hydrogen produced were 1.9 L per hour at a cell voltage of 1.5 V at 700 °C – all thanks to a layered perovskite with excellent electrochemical properties. This is four times higher hydrogen production efficiency than the existing high-efficient water electrolytic cells.
Image and content: UNIST