Computational Simulation of Lithium Ion Transport through Polymer Nanocomposite Membranes

Presented here are the macroscopic transport mechanisms of lithium ion in clay-polymer nanocomposites membranes with potential use in lithium rechargeable batteries. Computational simulations of the lithium ion transport across the interface of an anode and a cathode provide information to tailor single ion conductors and, thus to enhance ionic conductivity of the membrane. These transport simulations demonstrate that the lithium concentration profile in the nanocomposite membranes decreases linearly as a function of time and position. This finding is surprising because the membranes are single ion conductor with transferences numbers approaching one. Thus, a deeper understanding is needed of the transport properties in a real system, in order to be able to tailor materials with high conductivity and high transference numbers. It is shown that a battery cell with a thinner clay-polymer membrane can deliver a much higher capacity than that of a thicker membrane while the cell voltage remain almost unchanged and under 4 volts.