Regensburg 2025 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 32: Transport in Materials: Diffusion, Charge or Heat Conduction
MM 32.4: Vortrag
Donnerstag, 20. März 2025, 15:45–16:00, H22
Lithium transport in Lithium Manganese Oxide as a function of temperature, concentration and grain size measured by operando optical microscopy — •Monica Mead1, Yug Joshi2, and Guido Schmitz1 — 1Institut für Materialwissenschaft, Universität Stuttgart, Heisenbergstr.3, 70569 Stuttgart — 2Max-Planck-Institut für Nachhaltige Materialien, Max-Planck-Straße 1, 40237 Düsseldorf
Common methods for the determination of diffusion coefficients in electrode materials require critical interpretation, as their formal derivations rely on restrictive assumptions (e.g. galvanostatic/potentiostatic intermittent titration technique (G/PITT), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV)). Alternatively, an optical method for studying ion transport in battery electrodes through operando microscopy can be applied. Here, the measurement of diffusion coefficients is done on thin films in lateral diffusion geometry and is based on an optical response upon ion intercalation. This allows measuring the diffusion coefficient as a function of temperature, concentration and grain size. In this work, diffusion of Li ions in Lithium Manganese Oxide (LMO) is studied by operando microscopy. The temperature dependence of the diffusion coefficient, providing the activation energy via the Arrhenius relation, and the diffusion coefficients for the bulk/grain boundaries of LMO can be determined. Additionally, it is possible to find the concentration dependence by an inverse Boltzmann-Matano method on concentration profiles derived from the intensity profiles along the diffusion direction.
Keywords: Chemical Diffusion; LMO; Li-ion Battery