Regensburg 2022 – scientific programme

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O: Fachverband Oberflächenphysik

O 57: Poster Wednesday: Electronic Structure

O 57.2: Poster

Wednesday, September 7, 2022, 18:00–20:00, P4

Bulk Ion Conductivity and Near Surface Composition of Ionic Liquid and Zwitterionic Salt Based Electrolytes for Lithium Battery Applications — •Fabian Ullmann, Joel Tayo, Anna Dimitrova, and Stefan Krischok — Institut für Mikro und Nanotechnologien, Institut für Physik, TU Ilmenau

In this contribution we focus on the bulk conductivity and the near surface composition of several tertiary electrolytes which consist of Ionic Liquid (IL), Zwitterionic salt (ZwS) and lithium salt. Two ILs and ZwSs are chosen: IL: 1-ethyl-3-methyl-imidazolium bis-(trifluoromethylsulfonyl)imide - [EMIm][Tf2N] and 1-butyl-1-methylpyrrolidinium bis-(trifluoromethylsulfonyl)imide - [BMP][Tf2N]; ZwS: 3-(3-methylimidazolium-1-yl)Propane-1- sulfonate and 3-(3-vinylimidazolium-1-yl)Propane-1-sulfonate. As lithium precursor - bis(trifluoromethylsulfonyl)imide - Li[Tf2N] was used. Different Li[Tf2N]/ZwS ratios are considered and studied. Electrochemical Impedance Spectroscopy (EIS) enables us to determine the ion conductivity of the electrolytes. The results reveal that the presence of ZwSs enhances the ion conductivity, although they itself are not ion conductive. Further, by using X-Ray Photoelectron Spectroscopy (XPS) we analyze the near surface chemical composition at UHV-conditions. The XPS analysis displays a cation/anion/ZwS distribution as depended on the concentration of Li[Tf2N] and the type of IL and ZwS used. The spectroscopic results revealed solute-solvent interactions which modify the ion mobility.