Unveiling transport mechanisms of cesium and water in operando zero-gap CO2 electrolyzers
In CO2 electrolyzers, balancing water and cations is vital. Through operando wide-angle scattering and fluorescence X-ray techniques, we observed H2O and Cs+ dynamics in the membrane electrode assembly. Cs+ migrates across the membrane and drags H2O along via electroosmosis. H2O diffusion enables Cs+ movement further into the gas diffusion electrode (GDE), leading to the GDE flooding issue. Electrolyte concentration regulation clarifies the correlation to selectivity changes, highlighting water/cation management importance.