Researchers at the Ulsan National Institute of Science and Technology (UNIST) have 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. A paper on the work is published in the journal Nano Energy.
Unlike existing aqueous metal-CO2 systems, the new battery is not only easier to manufacture, but also allows continuous operation with one type of electrolyte.
The newly-developed MF Mg-CO2 battery operates based on the indirect utilization of CO2 with facile hydrogen generation process, which leads to electrochemical performance of 64.8 mW cm−2 with a high Faraday efficiency (>92.0%). Over the 80 discharge-charge cycles, the outstanding cycling performance with the generation of triple gases, e.g., H2(g) under discharge and O2/Cl2(g) under charge mode, was attained without any degradation.—Kim et al.
Schematic configuration and operation principle for each battery system from organic to membrane-free battery. Credit: UNIST
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. 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.
(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.
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. Through this we have opened the door to electrochemical utilization of CO2 with indirect circulation for future alternative technologies.—Kim et al.
Jeongwon Kim, Arim Seong, Yejin Yang, Sangwook Joo, Changmin Kim, Dong Hyup Jeon, Liming Dai, Guntae Kim (2021) “Indirect surpassing CO2 utilization in membrane-free CO2 battery,” Nano Energy doi: 10.1016/j.nanoen.2020.105741