Year: 2026
Type: preprint
Abstract: Low-temperature carbon dioxide electrolysis (CO 2 E) provides a low-carbon-emission pathway to basic chemical products. While anion exchange membrane (AEM)-based CO 2 E can provide high selectivity towards carbon products, runtimes are far below industry requirements. Flooding is a major obstacle to long-term stability as it limits CO 2 access to the catalyst layer, but the reasons for continuous water fluxes to the cathode are poorly understood. Here we present a model-aided experimental analysis of the driving forces for flooding. By tracking high-frequency resistance, anolyte conductivity, and cathode water accumulation over 24-hour runtimes across a range of current densities, temperatures and anolyte concentrations, we reveal AEM ion gradients as the main driving force for both flooding and cation-crowding at the cathode catalyst. We then show how ion gradient management can maintain steady CO selectivity and increase maximum CO 2 E partial current densities, with temperatures acting as a primary factor in reducing ion gradients. Using these insights, we demonstrate stable CO production at 500 mA cm -2 on an ionomer-free Ag catalyst.
Source: ChemRxiv
Institution: Delft University of Technology
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7221700063