Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 98: Organic-Inorganic Systems V: Adsorption on Metals
O 98.5: Talk
Friday, March 11, 2016, 11:30–11:45, H24
On the Temperature-dependent Behavior of Ultrathin Ethylene Carbonate Films on Graphite(0001) — •Maral Bozorgchenani1, Florian Buchner2, and R. Jürgen Behm1,2 — 1Ulm University, Institute of Surface Chemistry and Catalysis, D-89069 Ulm, Germany — 2Helmholtz Institute Ulm (HIU) Electrochemical Energy Storage, D-89081 Ulm, Germany
The interaction of ethylene carbonate (EC) with graphite(0001) as a model for the anode|electrolyte interface in Li-ion batteries was investigated under ultrahigh vacuum conditions. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIRS) were employed. After vapor deposition of a monolayer on graphite at 80 K the XP C1s and O1s spectra reveal the adsorption of intact adsorbed molecular adsorbates. Upon slow annealing the intensity of the XP signals related to EC drastically decreases in the temperature range between 190 and 210 K, mainly due to desorption. Subsequently, peaks with low intensity are still visible, which is related to decomposition products on the surface. FTIRS measurements at 80 K demonstrate modes of molecularly adsorbed EC. Difference spectra (background of the EC covered surface) recorded upon annealing reveal the evolution of bands with positive amplitudes (120 - 210 K) which are related either to molecular rearrangement effects or the formation of new species, and with negative amplitudes due to the loss of EC. At 210 K no EC is detected any more. The nature of the EC decomposition products is discussed and a comparison with our previous results on Cu(111) is given.