Carbon corrosion in low-temperature CO 2 electrolysis systems

Carbon corrosion has been widely documented in electrochemical systems such as fuel cells and water electrolyzers. In these systems, CO 2 is neither a reactant or a product, and CO 2 produced from carbon corrosion can be directly measured and attributed to the carbon corrosion process. In CO 2 electrolysis, the CO 2 feed masks the detection of CO 2 produced from anodic carbon corrosion, making the quantification of carbon corrosion difficult. Additionally, current CO 2 electrolysis systems operate in a different chemical environment than fuel cells and water electrolysis systems, often employing a carbonate-based anolyte. Understanding and quantifying failure modes is critical for the commercialization of CO 2 electrolysis, where a durability of multiple years is required. However, at present, many published studies employ carbon-based materials on the anode. These carbon-based anodes may corrode and deteriorate under the oxidative potentials present on the anode under normal CO 2 electrolysis operation. Carbon corrosion at the anode may also be convoluted with other common degradation mechanisms, making quantification of specific degradation pathways more challenging. Here, we have developed an ex situ carbon corrosion test for CO 2 electrolysis that allows for the quantification of mass loss from carbon corrosion. Using this test, significant carbon corrosion has been quantified at realistic anodic voltages experienced in operating CO 2 electrolysis cells. Based on these results, and informed from the past experiences in the development of fuel cell and water electrolysis systems, we provide a perspective on the use of carbon-based materials on the anode of CO 2 electrolysis systems. The CO 2 utilization community would benefit from rapidly transitioning away from the use of carbon-based materials on the anode of CO 2 electrolysis systems. If carbon materials are used on the anode in CO 2 electrolysis systems, it is only appropriate for short-term (