Hysteresis in the MD Simulations of Differential Capacitance at the Ionic Liquid-Au Interface

Iuliia V Voroshylova; Heigo Ers; Borja Docampo-Álvarez; Piret Pikma; Vladislav B Ivaništšev; M Natália D S Cordeiro

doi:10.1021/acs.jpclett.0c03212

Hysteresis in the MD Simulations of Differential Capacitance at the Ionic Liquid-Au Interface

J Phys Chem Lett. 2020 Dec 17;11(24):10408-10413. doi: 10.1021/acs.jpclett.0c03212. Epub 2020 Nov 30.

Authors

Iuliia V Voroshylova¹, Heigo Ers², Borja Docampo-Álvarez², Piret Pikma², Vladislav B Ivaništšev², M Natália D S Cordeiro¹

Affiliations

¹ LAQV@REQUIMTE, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal.
² Institute of Chemistry, University of Tartu, Ravila 14a, Tartu 50411, Estonia.

PMID: 33253582
DOI: 10.1021/acs.jpclett.0c03212

Abstract

In this Letter, we report the first observation of the capacitance-potential hysteresis at the ionic liquid | electrode interface in atomistic molecular dynamics simulations. While modeling the differential capacitance dependence on the potential scan direction, we detected two long-living types of interfacial structure for the BMImPF₆ ionic liquid at specific charge densities of the gold Au(111) surface. These structures differ in how counterions overscreen the surface charge. The high barrier for the transition from one structure to another slows down the interfacial restructuring process and leads to the marked capacitance-potential hysteresis.