Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 20: Solid-Liquid Interfaces: Reactions and Electrochemistry - Experiment I

O 20.5: Vortrag

Montag, 20. März 2017, 17:30–17:45, WIL B321

Li-Ion Battery Anodes: Electrochemical Model Studies at the Electrode|Electrolyte Interphase — •Isabella Weber¹, Johannes Schnaidt², Carina Bodirsky¹, Thomas Diemant¹, and R. Jürgen Behm^1,2 — ¹Ulm University, Institute of Surface Chemistry and Catalysis, D-89069 Ulm, Germany — ²Helmholtz-Institute Ulm (HIU) Electrochemical Energy Storage, D-89081 Ulm, Germany

State-of-the-art Lithium-ion batteries (LIBs) consist of Li-intercalating electrode structures and blends of organic solvents mixed with Li-salts. During the charge/discharge process, a protective film forms at the electrode|electrolyte interface which is referred to as the solid-electrolyte interphase (SEI). Due to the complex composition of the electrodes (active material, binder, etc.) and the electrolyte, however, the processes leading to SEI formation are still a matter of discussion. For a more detailed understanding, we systematically studied model systems by varying the anode material (different graphite powders with or without binder) and electrolyte solvents (ethylene carbonate with LiPF₆). Cyclic voltammetry was applied to characterize the electrolyte decomposition. Post-mortem XPS allowed the elemental analysis of the reduction products, as well as a depth-profiling of the SEI formed at different scan rates. In-situ infrared spectroscopy, finally, provided additional information on the adsorbed intermediates accumulated during SEI formation. The influence of the different LIB components on the formation, composition and product distribution of the SEI and the implications of our model studies on the understanding of the SEI formation in LIBs will be discussed.