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MO: Fachverband Molekülphysik

MO 6: Metal Complexes

MO 6.4: Vortrag

Montag, 11. März 2019, 15:00–15:15, S HS 001 Biologie

Singlet Oxygen Reactivity with Carbonate Solvents Used for Li-ion Battery Electrolytes — •Matthias K. Roos¹, Anna T. S. Freiberg², Johannes Wandt², Hubert A. Gasteiger², and Regina de Vivie-Riedle¹ — ¹Department Chemie, Ludwig-Maximilians-Universität München, München — ²Lehrstuhl für Technische Elektrochemie, Technische Universität München, Garching

Increasing the energy density of modern Li-ion batteries is essential for their future widespread use in the automotive sector. To achieve this goal, new cathode active materials are required, for which mixed transition metal layered oxides are promising candidates. However, for high state of charge, the release of singlet oxygen was observed from these cathode materials, resulting in drastically reduced battery lifetimes. In this joint experimental and theoretical work, we investigate the reactivity of the commonly used battery electrolytes ethylene carbonate (EC) and dimethyl carbonate (DMC) towards singlet oxygen [1]. Employing Rose Bengal to photochemically generate singlet oxygen in the bare electrolyte solutions, gaseous products are detected and quantified by on-line mass spectrometry. With quantum chemical and on-the-fly dynamical calculations a two-step reaction cascade is proposed, leading to the same products as found in the experiment. The uncommon reaction of an alkane with singlet oxygen in the first step constitutes the key element, activating the molecules for their further decay. The reaction mechanism is verified by colorimetric product detection in solution.

[1] J. Phys. Chem. A 122 (2018), 8828–8839.