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O: Fachverband Oberflächenphysik
O 63: Poster Session V: Electron-driven processes at surfaces and interfaces
O 63.2: Poster
Wednesday, March 3, 2021, 10:30–12:30, P
Superoxide formation near DMSO/Cu(111) interfaces — •Angelika Demling1,2, Sarah B King3, and Julia Stähler1,2 — 1Institut für Chemie, Humboldt-Universität zu Berlin, Berlin — 2Fritz-Haber-Institut der MPG, Berlin — 3Department of Chemistry, University of Chicago, Chicago
DMSO is a common non-aqueous solvent with the potential to be used in lithium-oxygen batteries due to its ability to catalyze the superoxide formation [1]. In this study we investigate the electron dynamics in DMSO films on Cu(111) using time- and angle-resolved two-photon photoemission and disentangle the individual steps of charge transfer
leading to superoxide formation: Electrons are injected from the metal to the DMSO, where they form small polarons on sub-picosecond time scales. The subsequent trapping extends the electronic lifetimes to several seconds [2]. Under co-adsorption of O2 another intermediate state arises, whose binding energy is in good agreement with electrochemical data of superoxide [3]. A phenomenological model reproduces the time-dependent data and shows that trapped electrons act as precursors for the superoxide. Further, our data suggests that more superoxide is formed on the surface than in the bulk of DMSO after diffusion.
These results may contribute to a basic understanding of charge transfer processes in novel battery systems.
[1] K. M. Abraham, J. Electrochem. 162, A3021 (2015)
[2] S. B. King et al., J. Chem. Phys., 150, 041702 (2019)
[3] Donald T. Sawyer et al., J. Electroanal. Chem. 12, 90-101 (1966)