AsianScientist (Jan. 5, 2018) – In a study published in the journal Nano Energy, scientists in South Korea have developed a method for cost-effective and highly-efficient production of hydrogen.
As hydrogen fuel cells become increasingly popular, the efficient production of hydrogen from electrolysis of water is highly sought after. Solid oxide electrolyzer cells (SOECs) are devices used to perform electrolysis, and they typically consist of two electrodes and an electrolyte that are all in the solid-state.
Existing SOEC electrolytes allow the transport of either hydrogen or oxygen ions to the other electrode, but not both. For SOEC electrolytes that transport oxygen ions, water electrolysis occurs at the anode, resulting in the production of hydrogen. In contrast, SOEC electrolytes that transport hydrogen ions cause water electrolysis to occur at the cathode, resulting in the production of oxygen.
In the present study, a team of researchers led by Professor Kim Guntae of the School of Energy and Chemical Engineering at Ulsan National Institute of Science and Technology, in collaboration with Professor Lim Tak-Hyoung of Korea Institute of Energy Research and Professor Shin Jeeyoung of Sookmyung Women’s University developed a hybrid-SOEC using a mixed ionic conducting electrolyte that can transport both oxygen ions and protons at the same time.
In comparison to other SOECs and representative water-electrolysis devices reported in the literature, the proposed system demands less electricity for hydrogen production, while exhibiting outstanding electrochemical performance and stability. Moreover, the hybrid-SOEC exhibited no observable degradation in performance for more than 60 hours of continuous operation, implying a robust system for hydrogen production.
“In the hybrid-SOEC where this electrolyte was introduced, water electrolysis occurred at both electrodes, which resulted in a significant increase in the total amount of hydrogen produced,” the researchers said.
Layered perovskite with excellent electrochemical properties was used as the electrode of the hybrid-SOEC. By combining an excellent electrode material with the mixed ionic conducting electrolyte, the electrochemical performance of their hydrogen generating system was enhanced.
As a result, hydrogen was produced at a high rate of 1.9 liters per hour, at a cell voltage of 1.5 volts, at 700°C. The hydrogen production efficiency of the hybrid-SOEC is thus four times higher than that of existing water electrolytic cells.
The article can be found at: Kim et al. (2017) Hybrid-solid Oxide Electrolysis Cell: A New Strategy for Efficient Hydrogen Production.
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Source: Ulsan National Institute of Science and Technology; Photo: Shutterstock.
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