At 50 mA cm -2 , the cell voltage is measured at approximately 2.7 V. This potential alteration, leads to a rapid increase in Cs + intensity at the cathode catalyst-membrane interface in comparison to that at OCV and continues to increase slightly within the three scans shown in Figure . This variation suggests that the Cs + ions can surpass the Donnan exclusion potential and transfer across the AEM at this cell voltage, although the contributions of the Donnan exclusion potential are unclear. The movement across the AEM occurs in the presence of a potential drop, resulting in an electric field that serves as the driving force for migration. Building upon a similar experimental configuration as that used for this study, Hansen et al. deconvoluted the overpotential contributions of each component within the MEA. Their study revealed a significant decrease in the cathode overpotential when the catalyst was deposited onto the AEM, as opposed to onto the carbon substrate. This discovery suggests that most of the cathode potential drop occurs at the catalyst-membrane interface, providing a plausible explanation for the accumulation of Cs + ions at this particular interface.