Toward Standardization in CO ₂ Electrolysis: A Round Robin Study

ABSTRACT CO 2 electrolysis is an emerging technology for the sustainable production of fuels and chemicals. Its transition from laboratory‐scale research to real‐world application is strongly driven by both regulatory and strategic means, aimed at achieving net‐zero greenhouse gas emissions. To meet this goal, accelerated progress in CO 2 electrolysis research and technological development is essential to ensure economic viability. This requires clear performance targets, reference materials, and standardized testing protocols that serve as a basis for reliable performance comparison within the CO 2 electrolysis community. To address this need, a Round Robin experiment was conducted involving well‐established R&D entities in the field of CO 2 electrolysis. The objective was to identify and mitigate the main sources of experimental variability, thereby enhancing reproducibility. We found that especially the modes of temperature measurements and cell/anolyte heating alongside pressure fluctuations and overpressures during product analysis are considerable differences among labs, while adjustments to the initial electrochemical protocol helped in minimizing voltage spikes in changing operation. As a result of multiple measurement campaigns and in‐depth discussions among participants, a recommendation for a standardized testing protocol and test setup requirements for CO 2 electrolyzers are provided.