CO 2 Electroreduction in a Membrane Electrode Assembly Electrolyzer: Cell Potential Optimization

In order to move the carbon dioxide electroreduction (CO 2 R) technology forward towards industrial implementation, it is requested to develop electrochemical cells achieving the lowest cell voltages. Indeed, a critical barrier to the industrial deployment of CO 2 electrolyzers resides in the high cost of electricity required to operate the system. As a consequence, techno‐economic analyses have identified, for Cu‐based CO 2 R to C1–C3 products, a maximal target of 2.5 V for the cell voltage at current densities of at least 100–300 mA cm −2 . Among the various types of electrolyzers, membrane electrode assembly (MEA) cells have gained significant attention as they display the lowest cell voltages. Here we report an assessment of some key individual MEA system‐level parameters, including anode design, membrane selection, anolyte composition, CO 2 flow rate, temperature, which collectively influence the overall cell potential. We find that cell voltages in the 2.0–2.5 V range can be obtained, including with bicarbonate/carbonate electrolytes, while the lowest values were achieved in KOH.