To verify this idea, we generate a series of ligand functionalized PDMS with both Li + and Cu 2+ , and study the rheological behavior as well as the ionic conductivity of the material by varying the ratio between LiOTf and Cu(OTf) 2 (Li0.8Cu0.2 to Li0.2Cu0.8, the numbers after each metal indicates the mole ratio of PDMS:LiOTf:Cu(OTf) 2 = 1 : m : n). From the rheology plots, we see that the viscoelasticity of the mixed ion coordinated PDMS is similar to the Cu 2+ coordinated PDMS at the same salt concentration, because the much stronger coordination of Cu 2+ compared to Li + dominates the relaxation of the dynamic network (Figure ). A synergistic effect appears as expected when using Cu(OTf) 2 to replace a small amount of LiOTf in the coordinated PDMS; Li0.8Cu0.2 shows higher ionic conductivity as well storage and loss moduli than LiOTf (Figure ).