Diffusion pathway 2, which commences at an initially 4-fold coordination site, coordinated by three oxygen atoms in the upper layer and only one oxygen atom in the bottom layer (Fig. ), demonstrates an invariant activation barrier (0.14-0.15 eV) due to a change in diffusion mechanism when the interlayer spacing increased (Fig. ). For an interlayer spacing of 0.87 nm, the initial site is 0.15 eV higher in energy than the final site and the diffusion pathway involves two intermediate sites. The first intermediate site is equivalent to the final 5-fold coordination, however, predominantly bound to the bottom layer and thus corresponds to traversing the empty space in between. The second intermediate is analogous to that observed in the first pathway, which exhibits planar 4-fold coordination. However, as the interlayer spacing increases, the diffusion mechanism undergoes a transformation (Fig. ). This is due to the inability of oxygen atoms from the opposing side of the layer to serve as effective coordinators and the corresponding large barrier for Li + to jump to the opposing side, thus minimizing the site preference of the initial and final states. These findings demonstrate that Li + diffusion along a single site of the V2O5 bilayer is facilitated by a change in its operational mode as the interlayer spacing increases.