(590o) Improving the Operational Stability of Electrochemical CO2 Reduction Reaction Via Salt Formation Understanding and Management

The practical application of electrochemical carbon dioxide reduction reaction (CO₂RR) technology remains hindered by poor stability, primarily owing to salt formation at the cathode, which blocks reactant CO₂ mass flow. Here, using operando characterization tools, we tracked the salt formation process and quantified salt precipitation under varying device operational conditions, elucidating a potential mechanism and optimizing anolyte conditions for long-term (>1,000 h) operation CO₂RR to CO under >100 mA cm^–2. Liquid droplets carrying cations and (bi)carbonate ions were observed to migrate from the catalyst/membrane interface towards the backside of the gas diffusion electrode, driven by interfacial gas evolution and CO₂ flow. These droplets eventually dried, forming bicarbonate salt precipitates that blocked the gas flow channels. On the basis of these observations, we engineering the hydrophobicity of the cathode gas flow channels and tuned the input CO₂ to facilitate the salt removal and extend the operational stability.