Scaling-up CO2 membrane-electrode-assembly electrolyzers: from metrics to manufacturing and standardization

Membrane-electrode-assembly (MEA) CO2 electrolyzers have progressed from lab prototypes to large-area stacks and pilots, positioning the technology towards transfer to industrial pilots in the next decade. This short review presents the most important advances from roughly the past five years and offers a concrete picture of what a scaled-up CO2 MEA electrolyzer must look like to be implemented into industrial process chains and allow industrial technology transfer. We argue that researchers must view the complete system holistically and that the scale-up of these new technologies is more of a scientific endeavor - "scaling-up is science" - rather than a trivial development or engineering question.