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MM: Fachverband Metall- und Materialphysik

MM 32: Functional Materials IV

MM 32.1: Vortrag

Mittwoch, 28. März 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.