In the previous section the emphasis was on the growth dynamics of the passivation layer and the underlying mechanisms. We now consider the structures generated from the reactive simulations and focus on how they compare to the baseline electrolyte. Previous work addressing this question relied on manual generation of amorphous or crystalline structures of known passivation film components, such as Li 2 BDC and Li 2 EDC, and attempted to infer conductivity or activation energies from these structures. Remarkably, the authors showed that the diffusivity and activation energy of Li + within Li 2 EDC compares well with experimental measurements of the conductivity of synthetic SEI compounds. Although this has allowed a precise interpretation of the conduction properties of passivation layers, a drawback of that procedure is the manual generation of the amorphous or crystalline structures of the passivation film components. An important aspect of our work is to allow deriving these structures based on the initial liquid electrolyte structure. In order to illustrate this in more detail, we show the potential of mean force (PMF) based on the RDFs of Li + with the decomposition products during the reactive simulation in Figure (a). A remarkable distinction with respect to the Li + /EC PMF is that the depth of the first minimum is considerably increased. We suggest that this increase in the barrier depth is caused by the stabilizing ionic forces between the Li + and the negatively charged degradation products. In order to explore the effect of this increased binding affinity on the dynamic properties, we show in Figure (b) the time-dependence of the Li + MSD labeled with the corresponding coordination environment. It can be seen that EDC 2-and BDC 2- coordinated Li + s show a slower diffusion compared to Li + /EC structures. Importantly, the labeled structures (Li + coordinated to CO 2- 3 , EDC 2-and BDC 2-) were observed to be stable within the time window used for calculating the MSD (Figure in Supplementary Information), thus implying a well-defined structure-dynamics correlation. Overall the observations qualitatively agree with the result that the SEI-activation energy is considerably larger than the activation of the carbonate liquid electrolyte (see Supplementary Table ).