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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 39: Charged Soft Matter, Polyelectrolytes and Ionic Liquids

CPP 39.3: Vortrag

Dienstag, 17. März 2020, 10:00–10:15, ZEU 114

Transport properties of two water-in-salt electrolytes: LiTFSI and LiOTF — •Maedeh Zahedifar and Axel Groß — Institut für Theoretische Chemie, Universität Ulm, 89069 Ulm, Germany

Over the past two decades, “solvent-in-salt” electrolytes have gained attention as a promising electrolyte concept for safer energy storage applications. Water is in principle an ideal solvent, but it has only a small range of electrochemical stability, which does not allow it to be used in high-voltage batteries. However, this limitation can be overcome by using highly concentrated aqueous electrolytes together with LiTFSI and LiOTF [1], so-called water-in-salt electrolytes. In order to better understand the properties of solvent-in-salt electrolyte, we have performed molecular dynamics simulations [2] of mixtures of water molecules with either LiTFSI or LiOTF salts. SPC/E and Lennard-Jones parameters are used for the desription of water molecules and anions, respectively [3]. Values of the viscosity for both LiTFSI and LiOTF salts in water have been derived from the time integral of the stress tensor auto-correlation function. Besides the viscosity, we will discuss further properties of the electrolytes such as radial distribution functions and mean-square displacements, and we will also present results of first-principles electronic structure calculations addressing these electrolytes.

[1] L. Suo et al., Angew. Chem. Int. Ed. 55, 7136-7141 (2016).
[2] S. Plimpton, J. Comp. Phys. 117, 1 (1995).
[3] J. Chandrasekhar et al., J. Am. Chem. Soc. 106, 903 (1984).