Dresden 2014 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 18: Poster Session
MM 18.2: Poster
Montag, 31. März 2014, 18:00–20:00, P4
Thin-film cathodes for application in lithium ion batteries — •Martin Fiedler1, Frank Berkemeier1, and Guido Schmitz2 — 1Institut für Materialphysik, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany — 2Institut für Materialwissenschaften, Universität Stuttgart, Heisenbergstr. 3, 70569 Stuttgart
Lithium Cobalt Oxide (LCO) and Lithium Iron Phosphate (LFP) powder material is commonly used in commercial lithium ion batteries. In this work, thin LCO and LFP films between 200 and 5500 nm in thickness are prepared by magnetron sputtering. After deposition, the layers are characterized by X-ray diffraction, transmission electron microscopy, and electrochemical techniques like cyclic voltammetry and chronopotentiometry. The influence of a negative substrate bias during sputter-deposition and of post annealing between 400 and 700∘C is investigated, and it is found that the electrochemical performance of the layers significantly depends on both parameters. The preparation of films under optimized conditions gives smooth thin-film cathodes, with a maximum thickness of 5500 nm and a lateral size of 45 cm2. In case of LCO, this results in a lithium storage capacity up to 17 mAh. Despite their large thickness, the cathodes are mechanically stable and allow the investigation of transport kinetics without being influenced by interface effects. Moreover, they open the possibility to be used in technical lithium ion batteries, as substitutes for conventional powder cathodes.