Dresden 2026 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 46: Poster II

CPP 46.57: Poster

Thursday, March 12, 2026, 09:30–11:30, P5

Molecular insights into the anion-dependence of the double-layer capacitance — •Richard Schömig¹, Xuqiang Xu², Jana Zaumseil², and Alexander Schlaich¹ — ¹Institute for Physics of Functional Materials, Hamburg Technical University, Hamburg — ²Institute for Physical Chemistry, Heidelberg Universiy, Heidelberg

Mixed ionic-electronic conductors are promising candidates for organic electrochemical transistors (OECTs). Single-walled carbon nanotubes (SWCNTs), a key example, show transconductance and capacitance responses that are strongly influenced by the properties of the surrounding electrolyte [1]. To uncover the mechanisms governing this behavior, we perform molecular dynamics simulations of aqueous electrolytes containing ions of different sizes and concentrations under varying applied potentials. As a simplified model for the more complex SWCNT electronic structure, we here use graphene as the electrode material. Employing atomistic constant-potential simulations, we investigate how these electrolyte characteristics shape the interfacial structure and differential capacitance. Analysis of the hydrogen-bond network and associated free-energy changes highlights the central role of ion size in determining interfacial behavior.
[1] Xu, X.; Fresta, E.; Lindenthal, S.; Michel, E.; Zaumseil, J. ACS Appl. Mater. Interfaces 2025, 17(25), 37002-37011.

Keywords: Mixed ionic-electronic conductors; Single-walled carbon nanotubes; Molecular dynamics; Constant potential; Aqueous interface