Notably, ab initio molecular dynamics simulations revealed differences in the ion mobilities of interfacial Mg and O ions between rod-like and disk-like inclusions. Fig. shows that interfacial ion mobility is significantly increased around an Ag 18 disk relative to around an Ag 12 rod, which shows an interfacial ion MSD more similar to that of the Ag 8 nanocomposite from Fig. . This non-linear effect can help to account for the large ionic polarization in the studied disk-containing nanocomposites. In turn, it may also account for some of the shortcomings of a continuum model with a single parameter for interfacial permittivity, notably its overestimation of rod-like polarization and underestimation of diskbased nanocomposite polarization.