Regensburg 2013 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 15: Poster Session
MM 15.71: Poster
Montag, 11. März 2013, 18:00–20:00, Poster E
Mechanical influences on lithium ion battery electrodes — •Tobias Kitzler1, Jürgen Markmann1,2, and Jörg Weißmüller1,2 — 1Helmholz-Zentrum Geesthacht, Institut für Werkstoffmechanik, Werkstoffforschung — 2TU Hamburg-Harburg, Institut für Werkstoffphysik und Werkstofftechnologie
Lithium ion batteries have drawn major attention during the last years. One very promising attempt to get batteries with better performance is to reduce the structure size of the electrodes which leads to very high surfaces and therefore improved kinetics. Besides this, downscaling seems to be a promising way to omit crack formation due to volume change which is the most important capacity loss mechanism in lithium alloy negative electrodes. On the other hand, downscaling leads to mayor stress evolution due to volume change, which according to the thermodynamic Maxwell relations, changes the electrochemical potentials. This influence has been observed in different experiments, but was not yet quantitatively measured. Here a setup is presented which allows to quantitatively measure the influence of uniaxial strain on the electrochemical properties of lithium ion electrodes. Therefore, dense and nanoporous Au films, synthesised by sputtering of pure Au and Au32Ag68, followed by an electrochemical dealloying process respectively, on a polyimide substrate were oscillatory strained and the corresponding change of the chemical potential recorded and analysed with respect to its impact on the kinetics of the loading and unloading processes as well as microstructural changes of the electrode itself.