To validate the electrochemical performance the ME-cell it was benchmarked against the aforementioned LE-cell using nominally identical CCMs: Fumasep® FAA-3-50 membrane coated with Pt/C (0.4 mgPt cm -2 ) and NiFeOx (2 mgcat cm -2 ), cathode and anode respectively. Figure shows the performance achieved in the ME-cell compared to that of the LE-cell. The cell performance was comparable with reports from various groups for different materials: ≤ 2.1 V at ≈ 1 A cm -2 in 1 M KOH(aq) at temperatures ranging from 40 to 80 °C. Figure shows a comparison of the ME-cell and LE-cell high frequency resistance (HFR), which is considered to be the sum of the membrane resistance (Rmemb) and the electronic resistance (sum of contact resistances between flow-fields and PTLs and bulk PTL resistances, Rel). Given that identical configurations were tested in both cells, the ≈ 42 mΩ cm² difference in the HFR likely stemmed from a difference in component compression. As detailed in the methods (Section 4), the ME-cell used static screw-based compression, while the LE-cell used sustained pneumatic pressure. The total Rel of the steel plungers, Ni felt and carbon PTLs, along with the contact resistances, was measured by GEIS in the ME-cell and LE-cell, assembled without a membrane or catalyst and found to be ≈ 20 and 80 mΩ cm 2 respectively. Such variations are often seen in operando cells; the optimal cell design for imaging purposes deviates from the design needed for the best electrochemical performance.