Comparing the diffusion coefficients in LiOTf and LiTFSi, we can see that the mobility of the hydrogens on the PDMS chains is similar in LiTFSi and LiOTf, whereas the mobilities of counter anions are quite different: TFSi -is higher than OTf -. MD simulations of LiTFSi compared to LiOTf show that the bulkier, less polar TFSi -anion tends to have more frequent intercluster hopping, leading to an overall higher diffusivity (D T F Si -= 1.66 Å2 /ns, D Li + = 1.26 Å2 /ns). The cluster analysis from MD observations is provided in Figure , which is consistent with previous work on PEO-LiTFSi systems: there are mostly neutral ion pairs, but also a non-negligible concentration of negatively charged clusters, resulting in an overall asymmetric distribution. The distribution of charged clusters in LiTFSi is less symmetric compared to that of LiOTf, with overall more negatively charged clusters present in the system, indicating that Li + from LiTFSi interacts more strongly with the polymer chains. Furthermore, the diffusion coefficients of positively charged clusters tend to be slightly smaller than those of negatively charged clusters with the same constituent number of ions, due to the stronger local interaction between positively charged clusters and electronegative ligands on the polymer.