Electrochemical carbon dioxide capture to close the carbon cycle

Electrochemical CO2 capture technologies are gaining attention due to their flexibility, their ability to address decentralized emissions (e.g., ocean and atmosphere) and their fit in an electrified industry. In the present work, recent progress made in electrochemical CO2 capture is reviewed. The majority of these methods rely on the concept of pH-swing and the effect it has on the CO2 hydration/dehydration equilibrium. Through a pH-swing, CO2 can be captured and recovered by shifting the pH of a working fluid between acidic and basic pH. Such swing can be applied electrochemically through electrolysis, bipolar membrane electrodialysis, reversible redox reactions and capacitive deionization. In this review, we summarize main parameters governing these electrochemical pH-swing processes and put the concept in the framework of available worldwide capture technologies. We analyse the energy efficiency and consumption of such systems, and provide recommendations for further improvements. Although electrochemical CO2 capture technologies are rather costly compared to the amine based capture, they can be particularly interesting if more affordable renewable electricity and materials (e.g., electrode and membranes) become widely available. Furthermore, electrochemical methods have the ability to (directly) convert the captured CO2 to value added chemicals and fuels, and hence prepare for a fully electrified circular carbon economy.

Automated summary

Electrochemical CO2 capture technologies are gaining attention for their flexibility and potential to address decentralized emissions. These methods rely on pH-swing to capture and recover CO2, and are being analyzed for their energy efficiency and adaptability in a circular carbon economy. Although costly, they could become more viable with widespread availability of affordable renewable electricity and materials.