Berlin 2018 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 63: Polymer and Molecular Dynamics II
CPP 63.2: Talk
Thursday, March 15, 2018, 09:45–10:00, C 264
Enhancing the Lithium Ion Transport in Polymer Electrolytes – Plasticization and Shuttling — •Diddo Diddens1 and Andreas Heuer1,2 — 1Helmholtz-Institut Münster, Ionics in Energy Storage (IEK-12), Forschungszentrum Jülich GmbH, Corrensstraße 46, 48149 Münster, Germany — 2Institut für physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 28/30, 48149 Münster, Germany
Solid polymer electrolytes consist of a salt dissolved in an amorphous polymer matrix, resulting in mechanically stable and flexible ion conductors. However, at ambient temperatures, their conductivity is still too low for an efficient use in modern energy storages. To overcome this deficiency, the addition of a low-molecular additive such as an ionic liquid (IL) has been proposed. We demonstrate by molecular dynamics simulations that the way in which the IL enhances the lithium mobility can in principle be twofold: First, the IL can act as a plasticizer, enhancing the dynamics of the polymer segments and thus also the motion of the attached lithium ions [1,2], and second, for IL molecules that directly coordinate to the lithium ions, the IL may serve as a shuttle detaching the lithium ions from the slow polymer chains [3], resulting in a much larger enhancement. In this contribution, we screen a large range of electrolyte compositions to identify molar ratios facilitating fast ion transport to serve as a guideline for electrolyte optimization.
[1] D. Diddens, A. Heuer, ACS Macro Lett., 2013, 2(4), 322-326
[2] D. Diddens, A. Heuer, J. Phys. Chem. B, 2014, 118(4), 1113-1125
[3] D. Diddens et al., J. Electrochem. Soc., 2017, 164(11), E3225