Berlin 2008 – scientific programme

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DS: Fachverband Dünne Schichten

DS 16: Functional Oxides

DS 16.3: Talk

Tuesday, February 26, 2008, 17:45–18:00, H 2032

Sputter deposited LiCoO₂ films as cathode material in thin-film batteries — •Tobias Stockhoff, Frank Berkemeier, and Guido Schmitz — Institut für Materialphysik, Westfälische Wilhelms-Universität Münster, 48149 Münster (Westf.), Germany

LiCoO₂ films of a thickness between 50 and 200 nm are deposited onto a Si-substrate by ion beam sputtering using Ar as sputter gas. The films are prepared under different deposition conditions by varying substrate temperature and the partial pressure of the oxygen, respectively. The chemical, structural, and electrical properties of the films are studied by means of TEM, XRD, and electrical measurements. Analytical TEM shows an oxygen deficiency in films sputtered under pure argon atmosphere and demonstrates the increase of the oxygen content if films are sputtered under an argon-oxygen ratio of 1:2. Due to the increased oxygen content, a significant increase of the specific dc-conductivity of the layers of about two orders of magnitude is observed in the electrical measurements. While at lower substrate temperatures XRD measurements show a film structure similar to the LT-phase of LiCoO₂, at a substrate temperature of 600^∘C and an oxygen-argon ratio of 3:2 the HT-phase of LiCoO₂ is found, preferential orientated in <00l> direction. An electrochemical analysis of the films proves their potential for application in electrochemical cells.