Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 30: Inorganic/Organic Interfaces: Towards Application

O 30.6: Vortrag

Dienstag, 17. März 2015, 15:15–15:30, MA 043

Stability of thin layers of the ionic liquid [BMP][TFSA] on a rutile TiO₂(110) surface and co-deposition of Li — •Benedikt Uhl^{1, 2}, Maral Hekmatfar^{1, 2}, Florian Buchner^{1, 2}, Dorothea Alwast^{1, 2}, and R. Jürgen Behm^{1, 2} — ¹Ulm University, Institute of Surface Chemistry and Catalysis, D-89069 Ulm, Germany — ²Helmholtz-Institute Ulm (HIU) Electrochemical Energy Storage, D-89069 Ulm, Germany

Ionic liquids (IL) have attracted high interest because of their special chemical and physical properties; among others, the application in electrolytes of Li-ion batteries is a promising concept. To gain a better understanding of the fundamental molecular processes at the electrode|electrolyte interface, the interaction of n-butyl-n-methylpyrrolidinium-bis(trifluoromethylsulfonyl)imide [BMP][TFSA] with rutile TiO₂(110) was investigated by X-ray photoelectron spectroscopy (XPS) in grazing emission and scanning tunneling microscopy (STM) under UHV conditions at temperatures between 80 K - 630 K. [BMP][TFSA] on TiO₂(110) is stable and does not show decomposition up to around 470 K. Addition of Li, either before or after [BMP][TFSA] deposition, leads to a reaction of Li with the TiO₂ substrate and formation of a new Ti³⁺ species in the near surface region together with a new oxygen species. Thereby the [BMP][TFSA] stays intact, however, all its signals shift by roughly 1 eV to higher binding energies, which is most likely due to interactions with the new Ti³⁺ species in the substrate. Most important, the thermal stability of the [BMP][TFSA] is not affected by the Li-incorporation.