On the Transference Numbers and Inverse Haven Ratios of Ionic Liquids and Polymeric Ionic Liquids

In this study, we used atomistic computer simulations within a non-equilibrium molecular dynamics framework to probe the transference number and inverse Haven ratio of ionic liquids and polymerized ionic liquids. In contrast to the conventional expectations, we find that the transference number in in these systems is a constant at approximately 0.5 and independent of the degree of polymerization (DP). The inverse Haven ratio increases first with increasing DP and then decreases at larger DP. We demonstrate that such results arise as a consequence of the strong cation-cation correlated motions. Together, such findings challenge the premise underlying the pursuit of single ion conductors as a means towards enhanced transference numbers.