where F G) HI is the number density of mobile Ag + ions, F JGJKH is the total number density of Ag + ions, and L is the macroscopic activation barrier (Figure ). Consequently, even with an exceptionally low activation barrier of 0.05 eV, comparable to other superionic conductors like Cu2Se, only ~10% of the ions are thermally mobile (without an applied electric field) at any given time over the investigated temperature range. For higher activation barriers, this fraction stays well below 1%. This observation sheds light on the misconception of a "liquid-like" sublattice, given that temperatures of more than 1000 K would be necessary to even reach a 50% thermally mobile sublattice. While instantaneous mobile ion fractions on the order of several percent could be expected to significantly impact thermal transport within the phonon gas model, the nature of diffuson modes makes them less likely to be largely affected so long as the mode energies do not change drastically as more ions become mobile. This does not seem to be the case, nor does the magnitude of ionic conductivity suggest any significant thermal transport by ion mobility (see Supplemental Note 11).