Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 111: Oxides and Insulators: Adsorption II
O 111.2: Vortrag
Freitag, 16. März 2018, 10:45–11:00, MA 041
Electronic and Surface Chemical Properties of the Interface Diethyl Carbonate/Zirconia — •Markus Frericks, Natalia Schulz, Thomas Späth, Wolfram Jaegermann, and René Hausbrand — Oberflächenforschung, FB 11, TU Darmstadt, Deutschland
Interface phenomena and related reaction layers play a crucial role in the performance and stability of lithium ion batteries (LIB). Besides the study of naturally formed solid electrolyte interface (SEI) layers, artificial protection layers are investigated on their potential to improve the stability of interfaces in LIBs. Among several candidates, zirconia (ZrO2) was found to improve the cycle stability when used as thin film coating for cathode materials such as lithium cobalt oxide (LiCoO2). While previous studies focused on the discussion of the high fracture toughness of ZrO2 and thus mainly mechanical properties, we investigated the electronic and surface chemical properties of zirconia coated model electrodes by solvent adsorption.
The experiment was performed at the beam line UE56_PGM-1 at the photon source BESSY II in Berlin. Diethyl Carbonate (DEC), a commonly used solvent in the electrolyte of LIBs, was adsorbed in consecutive steps on a cooled sample of a thin ZrO2 layer on a Ti substrate. The steps were monitored by X-ray photoelectron spectroscopy, yielding the electronic and chemical structure at the interface. Compared to the adsorption on pristine LiCoO2, less reactions are observed. The results will also be discussed with respect to electron transfer through the layer system LiCoO2/ZrO2/DEC, evaluating the possibility for improved passivation by zirconia.