SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 25: Poster: Metal Substrates
O 25.3: Poster
Montag, 27. März 2023, 18:00–20:00, P2/EG
Formation of solid electrolyte interface from polycaprolactone — •Kazem Zhour1, Andreas Heuer1, and Diddo Diddens2 — 1WWU Münster, Münster, Germany — 2Institute Münster (IEK-12) Forschungszentrum Jülich GmbH, Münster, Germany
As for liquid electrolytes, studying the formation of the solid-electrolyte interface and its implications is one of the most important topics in solid-state batteries. In this study, DFT and AIMD calculations were performed to study the decompositions of polycaprolactone, one main constituent of the electrolytes, and its ending groups at the interface. Additionally, the computational lithium electrode method was applied to study the formation of the SEI under external voltage. The AIMD results suggest that the fragments are highly reactive on the Lithium slab where the fragmentation can be observed in less than 1 ps. The decomposition was triggered by the electrons transferred from the slab to the fragments. The electrochemical mechanism shows only slightly weaker energetics with respect to the non-electrochemical one, showing that Li anode readily reacts with the polymer. After the formation of passivation layers (Li2O, LiF or Li2CO3) on top of the anode, the calculations show that only one monolayer protects the molecules from being decomposed at the interface at short interval of time, where the LiF layer seems to have the most robust protection as compared to the other layers. The electrochemical window and the decomposition of the polymer fragments in the presence of a Li cation, TFSI anion, or LiTFSI ion pair without explicit interface have also been also investigated.