Review—CO₂ Separation and Transport via Electrochemical Methods

This review focuses on research advancements in electrochemical methods of CO₂ separation as part of the broader field of CO₂ capture. Such methods are a potentially effective way of separating CO₂ from dilute gas mixtures (e.g., flue gas, air) such that it can be sequestered or recycled for other purposes. Electrodialysis using a liquid electrolyte capture solution is the most thoroughly explored electrochemical approach for CO₂ capture. The purpose of this review is to provide a broad overview of developments in the field, highlighting and harmonizing relevant figures of merit such as specific energy consumption and faradaic efficiency. In addition, the use of alkaline membranes is separately surveyed as a promising means of electrochemical CO₂ separation, as their CO₂ transport phenomena are well understood within the context of alkaline fuel cells or electrochemical CO₂ reduction. Recent materials advancements enable the use and modification of these membranes to promote electromigration of (bi)-carbonate ions, the result being CO₂ concentration on the anode side of an electrochemical cell.