It is reasonable to connect the slope of the i-V curve to the activity of the overall reaction -the greater the slope, the less overpotential (or driving force) is needed to increase the current (Fig. ). The magnitude of this slope is consequently interpreted through an exchange current density, to which we will refer from now on as the micropolarization exchange current density (𝑖 0,𝑚𝑖𝑐𝑟𝑜 , Eq. 11a). The reciprocal of the slope corresponds to the charge transfer resistance at equilibrium, 𝑅 𝑐𝑡 * , providing a connection between 𝑖 0,𝑚𝑖𝑐𝑟𝑜 and the resistance probed by electrochemical impedance spectroscopy around the equilibrium potential (proven for a two-step reaction, see SI.M4).