Electrochemical methods for carbon dioxide separations

Abstract

The build-up of carbon dioxide in the atmosphere is one of the grand challenges facing society. Addressing this challenge by removing CO2 from the atmosphere or mitigating point source emissions through the separation and concentration of CO2 from these dilute sources requires reductions in energetic and monetary cost relative to traditional thermal and pressure swing methods. Electrochemical methods of CO2 separation have drawn increasing attention in recent years as potentially cheap, low-energy, scalable carbon capture technologies. In this Primer, we provide an overview of the experimentation and analysis needed for the study of electrochemical methods for CO2 separation, including a discussion of the considerations necessary for targeting the application of such techniques. This Primer focuses on ambient temperature techniques such as pH swing and direct redox processes, which utilize similar experimental set-ups. We include considerations on the choice of redox agent and an outlook on this growing body of research. Experimentation to address real-world conditions, particularly at practical oxygen concentrations, and novel system designs that overcome transport limitations or, potentially, couple capture and CO2 utilization are emerging areas in the field.