with 𝑑𝑄 𝑑𝑡 ⁄ being the dissociation rate written as equivalent current, 𝑘 & ( being the rate constant, the unknown function 𝑓 7,& ( for the influence of the O2 activity 𝑎 & ( and the activity of free reactant sites (Eq. 6a). The influence of dissolved O2 should be modeled in good approximation by collision theory and can be factored out with the stoichiometry 𝜈 & ( . The goal is now to find the remaining expression for 𝑓(𝑄), which is now a measure of the activity of free reaction sites, the stoichiometry 𝜈 & ( , and the rate constant Through using the power law in Eq. 5, the OCP-charge transients can be transformed to charge-time transients (Fig. ). By taking the derivative (Fig. ) and rearranging Eq. 6b so that the left-hand side is independent of 𝑎 & ( (Eq. 7), we can deduce that 𝜈 & ( = 1 as then the curves overlap for each rotation rate with different oxygen partial pressures (Fig. ). Since the groups of curves are ordered by the rotation rate 𝜔, it can be inferred that mass transport (MT) of 𝑂 ! plays a significant role, and the unknown function 𝑔(𝜔) is introduced to capture such an effect (Eq. 7b).