Regensburg 2019 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 20: Poster session II
MM 20.34: Poster
Dienstag, 2. April 2019, 18:30–20:00, Poster C
Optimization and characterization of rf sputtered LiCoO2 cathodes — •Marcel Couturier, Fabian Michel, Martin Becker, and Angelika Polity — Institute for Exp. Physics I and Center for Materials Research (LaMa), Justus Liebig University Giessen, Germany
LiCoO2 (LCO) thin films have been grown by rf-magnetron sputter-deposition on platinum-coated Al2O3 (c-sapphire) substrates. Deposition parameters such as substrate temperature and the partial pressure ratio between O2 and Ar were varied in order to find suitable parameters for a cathode offering reversible intercalation and deintercalation of lithium ions. Structural characterization was carried out using X-ray diffraction and Raman spectroscopy, revealing that the orientation as well as the crystallinity of the deposited LiCoO2 films can be influenced by varying the O2/Ar-ratio and simultaneously applying a sufficient substrate temperature during deposition. Furthermore, both the atomic composition and the atomic distribution were determined using X-ray photoelectron spectroscopy and secondary ion mass spectrometry. Results showed that the films are nearly stoichiometric and have a homogeneous atomic distribution throughout the entire depth profile. For electrochemical characterization, LiCoO2 thin films where charged and discharged against lithium metal while using a liquid electrolyte consisting of LiPF6 dissolved in a mixture of EC/DMC with a molar fraction of 1:1. Reversible discharge capacities in the order of up to 70 mAh/g could be achieved for optimized LiCoO2 thin films.