The electrodes were coated as circular points with a 1.5 mm diameter, arranged in an 11x11 square grid with each point spaced 4.9 mm apart. Details can be found in Section 3 of the supplementary materials. To evaluate the uniformity of the coating, these electrodes were analyzed using XRF. Figure illustrates the distribution of Fe signal intensity across the grid, with the colorbar reflecting the relative Fe content as determined by the integrated signal at each point. As a direct measurement of the active material mass on this type of coating is challenging, the Fe signal in XRF images was used as a proxy for estimating Fe distribution and the active material content. By weighing the Al-foil before and after coating and drying, an average active material mass of 0.0218 mg was calculated. The Fe count per second (CPS) is centered around a central peak, indicating an underlying normal distribution with a maximum spread of ±6.5%, as depicted in Figure . Our two distinct sets of measurements are represented by red and blue markers in Figure . The color distribution across the grid indicates a uniform Fe coating, although some areas exhibit higher or lower concentrations. This is crucial for evaluating the consistency of the screen-printing process. The XRF spectrum of a representative coated point is shown in Figure and features Fe peaks at 6.41 keV and 7.06 keV. While the spectrum is primarily characterized by Fe, minor peaks for Cr and Ni indicate their subordinate presence. Additional elements including P and Al, with peaks at 2.02 keV and 20.19 keV respectively, are also identified. The peaks, with lower CPS, are detailed in Supp.3. In the electrochemical procedures, such as galvanostatic cycling, this data can be utilized for setting the correct current to achieve the desired C-rate during charging and discharging protocols. For CV, as employed in this study, the information is essential to normalize the obtained current response.