Berlin 2012 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 32: Functional Materials IV
MM 32.1: Talk
Wednesday, March 28, 2012, 11:30–11:45, H 0106
Studying the lithium deintercalation in thin LiCoO2 films by electro-chromatic measurements — •Tobias Stockhoff, Tobias Gallasch, Frank Berkemeier, and Guido Schmitz — Westfälische Wilhelms-Universität Münster, Institut für Materialphysik, Münster (Westf.), Germany
LiCoO2 powder is one of the important components of today‘s lithium ion battery technology. In this work, we investigate thin LiCoO2 films with respect to the intercalation/deintercalation of lithium ions, for potential application in all solid-state thin film batteries. For this purpose, LiCoO2 films between 5 and 400 nm in thickness, were deposited onto ITO-coated glass substrates by rf-ion beam sputtering. The structure and stoichiometry of the films was checked by means of transmission electron microscopy (TEM), while basic electrochemical properties of the layers were studied by chrono-amperometry, cyclic voltammetry (CV), and galvanostatic intermittent titration technique (GITT).
Additionally, the reversible intercalation and deintercalation of lithium is demonstrated by measuring the optical transmission through the thin film system, since the colour of the LiCoO2 films strongly depends on their lithium concentration. Using this electro-chromatic effect, the diffusion coefficient of lithium inside the films is determined, and the local lateral distribution of lithium is studied in-situ, using optical microscopy.