Computer simulations of cyclic voltammetry were performed in Comsol 6.0 using the electrochemistry module. The simulations were performed in a 1D geometry with the electrode at one end of the simulation interval and a constant concentration as boundary condition at the other end. The cyclic voltammogram at a scan rate of 5 Vs -1 was fitted manually. This high scan rate was chosen because a clear reverse peak could be seen. A more detailed description of the simulations can be found in the SI.