Berlin 2015 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 6: Functional Materials I: Battery Materials
MM 6.5: Vortrag
Montag, 16. März 2015, 11:15–11:30, TC 010
Charging-induced defects in Li1−xCoO2 battery electrodes — •Gregor Klinser1, Stefan Topolovec1, Peter Parz1,4, Heinz Krenn2, Harald Kren3, Stefan Koller3, and Roland Würschum1 — 1Institute of Materials Physics, Graz University of Technology, Austria — 2Institute of Physics, University of Graz, Austria — 3VARTA Micro Innovation GmbH, Graz, Austria — 4now at: Magna Steyr Battery Systems GmbH & Co OG, Zettling, Austria
Research in the field of modern battery materials demands characterization techniques which allow an inspection of atomistic processes during battery charging and discharging. In the present work, SQUID magnetometry is combined with positron annihilation spectroscopy to study the battery cathode material Li1−xCoO2 in dependence of the degree of charging.
Positron annihilation measurements reveal vacancy-type defects on the Li-sublattice the size of which increases with Li-extraction [1]. The concomitant increase of the magnetic moment with Li-extraction by SQUID magnetometry cannot exclusively be attributed to Co3+→ Co4+ oxidation, however, may also involve oxygen states.
In the vicinity of the reversibility limit of charging, a sharp drop of the localized magnetic moment is observed, which may be linked to the Li vacancy reordering recorded by positron annihilation spectroscopy [1].
[1] P. Parz, B. Fuchsbichler, S. Koller, B. Bitschnau, F. Mautner, W. Puff and R. Würschum, Appl. Phys. Lett. 102, 151901 (2013).