ABSTRACT Anion exchange membrane water electrolysis (AEMWE) holds promise as a low‐cost, efficient hydrogen production method, but its internal polarization mechanisms remain poorly resolved. A precisely controlled single‐cell experimental platform is developed to completely decouple ionic transfer, charge transfer, and mass transfer processes under realistic operating conditions. Distribution of relaxation times (DRT) analysis assigns each resolved spectral peak to specific polarization processes, and the assignments are validated through carefully designed variations in membrane thickness, electrocatalysts, temperature, and flow rate. Based on these results, a frequency‐mechanism map is constructed and applied to quantify impedance evolution across a wide range of current densities. The shifting contributions of dominant polarization processes are clearly revealed, and a robust, experimentally supported framework for interpreting impedance spectra in AEM systems is established. This work provides a mechanism‐specific diagnostic reference and guidance for future optimization and control strategies in AEM electrolyzers.
Fang et al. (Sun,) studied this question.