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O: Fachverband Oberflächenphysik

O 15: Organic Molecules on Inorganic Substrates II: Electronic, Optical and other Properties

O 15.12: Vortrag

Montag, 18. März 2024, 17:45–18:00, MA 043

Simulating Smart Surfaces for Lithium Ion Batteries — •Fabian Dietrich — Departamento de Ciencias Físicas, Universidad de La Frontera, Temuco, Chile

Self-assembled monolayers (SAM) are a common tool for the functionalization of surfaces. Such surfaces can be used form controlable solid electrolyte interfaces (SEI) on cathode materials for lithium ion batteries. Using photo-switchable organic molecules for the formation of the SAM yields a controlabilty of the surface properties - a so-called smart surface. These smart surfaces are supposed to be used to avoid undesired charge (and with that energy) loss in a fully charged lithium ion battery.

For being used as smart surface, the organic molecules have to fulfill the following requirements: 1.) A photo-switchable moiety with both photoisomers separated by at least 5000 cm⁻¹; 2.) Having polar functional groups for the interaction with the metal oxide surface; 3.) Both photo-isomers can build a stable SAM and 4.) The structural rearrangement upon photo-switching is large enough to influence the Li ion insertion and small enough to keep the SAM stable. For this challenge, we applied density functional theory (DFT) to evaluate different molecules with respect to their aggregation behavior on the previously studied vanadium pentoxide surface and subsequently different diffusion pathways through a SAM of the selected molecules.

Keywords: DFT simulations; Lithium Ion Batteries; Photo-switchable Molecules; Self-assembled Monolayers; Diffusion