The operating cell voltage can be found for a given pair of anode and cathode half-reactions from the difference between the absolute potentials of the anode and cathode at a matched current when taking the electrode areas into account. Here, electrodes with 1 cm 2 geometric areas were used in each experiment, so it is equivalent to match the current densities on the anode and cathode. A LLA including a BPM requires the addition of the rectifier voltage drop, VBPM = -0.83 V, to initiate current through the membrane. Therefore, the predicted operating cell voltage (Vop) for a current density of -10.0 mA cm -2 through the cathode can be predicted from the half-cell potentials of the cathode (Ecat) at -10.0 mA cm -2 , and anode (Ean) at +10.0 mA cm -2 , respectively: 𝑉 𝑜𝑝 = 𝐸 𝑐𝑎𝑡ℎ -𝐸 𝑎𝑛 + 𝑉 𝐵𝑃𝑀 = ∆𝐸 + 𝑉 𝐵𝑃𝑀 . The operating potential is defined with convention that Vop < 0 V indicates that the pairing forms an electrolytic cell.