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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 19: Energy Storage and Batteries II
CPP 19.6: Talk
Tuesday, March 19, 2024, 10:45–11:00, H 0111
Investigation of Li depth profiles in Si/graphite anodes from Li-ion battery cells via NDP and GD-OES — •Ivana Pivarníková1,2, Marius Flügel3, Neelima Paul1, Antonino Cannavo4, Giovanni Ceccio4, Jiří Vacík4, Peter Müller-Buschbaum1,2, Margret Wohlfahrt-Mehrens3,5, Thomas Waldmann3,5, and Ralph Gilles1 — 1TUM, MLZ, Garching, Germany — 2TUM School of Natural Sciences, Chair for Functional Materials, Garching, Germany — 3ZSW, Ulm, Germany — 4NPI, CAS, Rez, Czech Republic — 5HIU, Ulm, Germany
The loss of Li inventory is a common aging mechanism in Li-ion batteries. To better understand the underlying reversible and irreversible degradation processes in Si/graphite electrodes, depth-resolved methods need to be used to obtain information on the decomposition products of the Li-containing electrolyte across the electrode thickness. In this work we present two Post-Mortem analytical methods, which can be used to obtain quantified Li depth profiles to depths bigger than 10 µm from the electrode surface, the neutron depth profiling (NDP) and glow discharge optical emission spectroscopy (GD-OES). The validation of GD-OES using NDP by examining the Si/graphite anodes from cylindrical 21700 cells is presented. These two methods are complementary to each other. It has been demonstrated that the preferential sputtering can occur on the anode surface during the GD-OES measurements. This phenomenon is caused by the higher sputter rate of Li, as it is mainly present in the Li plated layer or in the solid electrolyte interface (SEI).
Keywords: Lithium-ion batteries; Li plating; neutron depth profiling; silicon graphite anodes