At times longer than 5 ns, the ion motion becomes diffusive and the diffusion coefficient can be obtained from the MSD by applying the Einstein relation (Equation ( )). The OTf -diffusion coefficient (D OT f -= 1.12 Å2 /ns) is larger than the Li + diffusion coefficient (D Li + = 0.84 Å2 /ns). The results show that both cations and anions are mobile in the polymer matrix, with anions having higher mobility than cations. We infer that the motion of cations is mainly through the ligand exchange process, and is slowed down by this transient coordinating interaction; in contrast, anions are less confined and the motion is facilitated by chain segmental motion. The PDMS chains also diffuse over time, but at a much slower rate than the ions. For Mix, the MSD curves of cations and anions (Figure ) almost coincide, with similar diffusion coefficients of D Li + = 2.75 Å2 /ns and D OT f -= 2.78 Å2 /ns). This is due to the poor solvation ability of pristine PDMS, which promotes the formation of ionic clusters and results in the cations and anions diffusing together. Interestingly, the diffusion coefficients of both the ions and the chains in Mix are about three times larger than their values in LiOTf, resulting from the fact that ion motion in Mix encounters less confinement from the PDMS chains due to minimal coordination. At first glance, this seems contrary to our experimental results since ionic conductivity is typically thought to be directly related to the diffusion coefficient. However, the presence of ionic clusters instead of single ions significantly decreases the amount of charge carriers in the system, and therefore yields low ionic conductivity of the material.