Mar 17, 2021 |
Novel system produces hydrogen and electricity while eliminating carbon dioxide
(Nanowerk News) A recent study, affiliated with UNIST has unveiled a novel system, capable of producing hydrogen and electricity quickly and effectively while eliminating carbon dioxide (CO2) emissions significantly.
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Published in Nano Energy ("Indirect surpassing CO2 utilization in membrane-free CO2 battery"), this breakthrough has been carried out by Professor GunTae Kim and his research team in the School of Energy and Chemical Engineering at UNIST.
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In this study, the research team succeeded in developing a membrane-free aqueous metal–CO2 battery. Unlike the existing aqueous metal–CO2 systems, the new battery is not only easier to manufacture, but also allows continuous operation with one type of electrolyte.
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Figure 1. Schematic configuration and operation principle for each battery system from organic to membrane-free battery. (Image: UNIST) (click on image to enlarge)
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The research team designed a membrane-free (MF) Mg-CO2 battery, as an advanced approach to sequester CO2 emissions by generating electricity and value-added chemicals without any harmful by-products.
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According to the research team, their MF Mg-CO2 battery operates based on the indirect utilization of CO2 with facile hydrogen generation process. It has been also found that the new battery exhibits high faradaic efficiency of 92.0%.
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“In order to translate the newly-developed laboratory-scale MF Mg-CO2 battery technology into a commercial reality, we have envisioned an operational prototype system that produces electricity and value-added chemicals, as a cornerstone to better support sustainable human life from CO2 and earth-abundant renewable power (e.g., wind, solar, seawater),” noted the research team.
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The MF Mg-CO2 battery system has a structure similar to that of hydrogen fuel cells for use in cars, since it only requires a Mg-metal negative electrode, an aqueous electrolyte, and a positive-electrode catalyst. However, unlike the existing fuel cells, they are based on aqueous electrolytes.
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As a result, the newly-developed MF Mg-CO2 battery had successfully sequestered CO2 emissions by generating electricity and value-added chemicals without any harmful by-products.
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Figure 2. (a) Schematic illustration of MF Mg-CO2 battery. (b) The XRD profile of the precipitated white solid after discharge process in CO2 sat’d condition and N2 sat’d condition. (Image: UNIST) (click on image to enlarge)
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“Our findings indicate great benefits for the newly-developed MF Mg-CO2 battery technology to produce various value-added chemicals of practical significance and electricity from CO2 without any wasted by-products,” noted the research team. “Through this we have opened the door to electrochemical utilization of CO2 with indirect circulation for future alternative technologies.”
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