Conductivity and Transference Numbers in Lithium Salt-doped Block Copolymeric Ionic Liquid Electrolytes

POSTER

Abstract

We present multiscale molecular dynamics simulation results comparing the conductivity and transference numbers in lithium salt-doped polymeric ionic liquids (PolyILs) and the lamellar phases of block copolymeric ionic liquids (coPolyILs). In both systems, the anion mobilities decreased with salt loading. Lithium ions exhibited negative mobilities in both systems, but the magnitudes decreased with increase in salt concentrations. More interestingly, the anion mobilities were lower in the lamellar systems compared to homopolymers in magnitude, but the lithium ion mobilities and the transference numbers were less negative in such systems. We examine the anion-cation and lithium-anion interactions in terms of radial distribution functions, coordination characteristics and ion pair relaxation timescales. Based on such analyses, we rationalize the salt concentration dependencies as a result of the interfacial interactions in lamellar systems, and the competition between anion-cation and lithium-anion interactions in both PolyILs and coPolyILs. Overall, the findings presented in this study demonstrates that the modified anion-cation and lithium-anion interactions in the microphase separated coPolyILs may provide a strategy for realizing higher lithium ion transference numbers relative to the homopolymeric counterparts.

* The authors work on the topic of ion transport in polymer electrolytes have been generously supported by grants from Robert A. Welch Foundation (Grant F1599), the National Science Foundation (DMR-2225167). The development of the non-equilibrium simulation methodology for ion conductivities was supported as part of the Center for Materials for Water and Energy Systems, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award #DE-SC0019272.

Presenters

  • Zidan Zhang

    The University of Texas at Austin, University of Texas at Austin

Authors

  • Zidan Zhang

    The University of Texas at Austin, University of Texas at Austin

  • Jakub Krajniak

    Independent researcher

  • Jacob Sass

    MIT

  • Harnoor S Sachar

    The University of Texas at Austin, University of Texas at Austin

  • Nico Marioni

    The University of Texas at Austin, University of Texas at Austin

  • Tyler J Duncan

    The University of Texas at Austin, University of Texas at Austin

  • Venkatraghavan Ganesan

    University of Texas at Austin, The University of Texas at Austin