Room-temperature carbon capture cell ‘uses less energy than conventional systems’

A new carbon capture system can “easily” grab and release carbon dioxide (CO2), its creators have claimed, operating at room temperature and reportedly using less energy than conventional systems.

The system, which uses an electrochemical cell, was developed by researchers reporting in the American Chemical Society’s ACS Central Science journal.

Many industries are turning to electrification to help curb carbon emissions, but this technique is not feasible for all sectors. CO₂ is a by-product of several stages of cement manufacture, for example, causing a major contribution to carbon emissions.

Excess gas can be trapped with carbon capture technologies, which typically rely on amines to help ‘scrub’ the pollutant by chemically bonding to it. This also requires lots of energy, heat and industrial equipment, however, which can burn even more fossil fuels in the process.

Carbon capture could instead be electrified using electrochemical cells powered by renewable energy, according to Fang-Yu Kuo, Sung Eun Jerng and Betar Gallant. The ACS researchers set out to develop an electrochemical cell that could easily and reversibly trap CO₂ with minimal energy input.

The team first developed an electrochemical cell that could both catch and release emitted carbon by ‘swinging’ positively-charged ions, known as cations, across a liquid amine dissolved in dimethyl sulfoxide. When the cell was discharged, a strong Lewis cation interacted with the carbamic acid, releasing CO₂ and forming the carbamate amine. When the process was reversed and the cell charged, the cation was removed, and the cell could capture CO₂ and reform the carbamic acid in the process.  

The researchers optimised the ion-swinging process with a combination of potassium and zinc ions. In a prototype cell, they used these two ions as the basis for the cell’s cathode and anode. “This cell required less energy than other, heat-based cells and was competitive with other electrochemical cells in initial experiments,” a research announcement said.  

They also tested the device’s long-term stability, and found that nearly 95% of its original capacity was maintained after several cycles of charging and discharging. “This work shows that an electrochemical alternative is possible and could help make continuous CO₂ capture-release technologies more practical for industrial applications,” the announcement added.

The work was funded by the Massachusetts Institute of Technology Research Support Council.

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