Dresden 2017 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 22: Poster session I

MM 22.32: Poster

Montag, 20. März 2017, 19:00–20:00, P4

Optical characterization of thin-film electrode materials during electrochemical measurements — •Tim Theil, Nelly Sanchez, Yug Joshi, Susann Nowak, and Guido Schmitz — Institut für Materiawissenschaft, Universität Stuttgart

Thin-film battery electrodes are mainly characterized using electrochemical methods like cyclic voltammetry and chronopotentiometry. Using optical measurements additional insights into processes happening in the electrode materials or at the interfaces during cycling can be gained. Monitoring in-situ during lithiation and delithiation can give insight into chemical reactions or thickness changes. The approach is proven using lithium cobalt oxide (LCO) as an example for a cathode and lithium titanate (LTO) as an example for an anode. Both materials were prepared by ion beam sputter deposition on platinum coated silicon wafer with oxygen as reactive gas. LCO was crystallized by post annealing at 600°C whereas LTO was in situ annealed at 600°C. For the measurement a liquid cell with a three electrode setup was used where the used electrolyte was 1 molar LiClO4 in EC:DMC, the counter and the reference electrode was pure lithium metal. During cycling the sample was illuminated in a 45° angle by a tungsten source and each second a reflectance spectrum was acquired at 90° to the incoming beam. The reversible dependence of the optical properties on the charge state of the materials can be clearly shown.