This corresponds to a cell potential of: VBPM = -ΔG/(n F) = -0.83 V, where n = 1, the number of electrons total required per molecule of water dissociation, and F is Faraday's constant. This can be understood as an electrochemical cell by coupling Equation S1 as the cathode reaction occurring at the cation exchange layer of the BPM and Equation S3 as the anode reaction at the anion exchange layer. These are roughly the electrolyte conditions within the corresponding layers of the BPM itself.