Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 27: Organic/bio Molecules on Metal Surfaces III
O 27.8: Vortrag
Dienstag, 1. April 2014, 12:15–12:30, TRE Phy
Temperature-induced Structural and Chemical Changes of Ultrathin Ethylene Carbonate Films on Cu(111) — •Florian Buchner1, Maral Bozorgchenani1,2, Hanieh Farkhondeh1,2, Benedikt Uhl1,2, and R. Jürgen Behm1,2 — 1Helmholtz Institute Ulm (HIU), Ulm, Germany — 2Ulm University, Institute of Surface Chemistry and Catalysis, Ulm, Germany
Ethylene Carbonate (EC) is a key component in Li-ion battery electrolyte. A molecular scale understanding of the solid-electrolyte interphase (SEI) is crucial to improve the Li-ion battery performance. The adsorption and reaction of EC on Cu(111), as a model system, was investigated with scanning tunnelling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) under ultrahigh vacuum (UHV) conditions. Highly ordered 2D EC islands were obtained on Cu(111) at submonolayer and monolayer coverage by STM for adsorption at around 100 K. The adsorption behaviour is discussed in terms of intermolecular interactions and mobility on the surface. The XP C1s and O1s core level spectra prove the adsorption of intact EC molecules. Between 80 K and 420 K, significant structural and chemical changes were detected. Upon heating to room temperature, a highly mobile molecular adlayer is detected by STM. Upon post annealing and cool down to around 100 K a transformation from 2D EC islands into islands with arbitrary shapes is observed. Variable temperature XPS resolves chemical changes of the adlayer upon heating, including desorption of molecular species and decomposition of EC into new surface species.