48.6 %) in a Mg nanoparticle, followed by Mg(1010)A (23.9 % vs. 27.9 %) and Mg(0001) (19.2 % vs. 23.7 %). Therefore, the accurate description of these occurring surface terminations is most important when studying the Mg anode in MIBs. 37 are significantly overestimated by ≈ 0.2 eV. Moreover, according to DFT, adsorption at the fcc site is considered to be 0.02 eV more stable than at the hcp site. However, it is impossible to distinguish between the two adsorption sites in ReaxFF without using angular terms or increasing the bond order cutoff, as already explained in the case of the cohesive energy of the hcp and fcc crystals. Besides, the relative stability sequence of the adsorption sites on Mg(0001) is well reproduced. For example, the fcc and meta-stable ontop positions differ by To obtain a smooth potential energy surface (PES), which is key to performing meaningful MD simulations, we added activation energy values of selected self-diffusion processes to the training set. Our goal was to introduce a diverse spectrum of different magnesium conformations but also of transition states into the training set. For the latter, we included terrace self-diffusion barriers on Mg(0001), Mg(1010)A, and Mg(1011) (Figure , Table ), but also additional diffusion processes of the terrace-step-kink (TSK) model (dimer, trimer, step-edge, kink, inner-corner, outer-corner, step-down on Mg(0001); dimer, trimer on Mg(1011)).