Impedance of nanocapacitors from molecular simulations to understand the dynamics of confined electrolytes

• DOI: 10.1073/pnas.2318157121
• Publication Date: 2024-04-25T16:39:02Z
• Authors: Giovanni Pireddu; Connie J. Fairchild; Samuel P. Niblett; Stephen J. Cox; Benjamin Rotenberg
• Keywords: Dynamics

Nanoelectrochemical devices have become a promising candidate technology across various applications, including sensing and energy storage, provide new platforms for studying fundamental properties of electrode/electrolyte interfaces. In this work, we employ constant-potential molecular dynamics simulations to investigate the impedance gold-aqueous electrolyte nanocapacitors, exploiting recently introduced fluctuation-dissipation relation. particular, relate frequency-dependent these nanocapacitors complex conductivity bulk in different regimes, use connection design simple but accurate equivalent circuit models. We show that interfacial contribution is essentially capacitive response bulk-like even when interelectrode distance only few nanometers, provided latter sufficiently large compared Debye screening length. extensively compare our simulation results with spectroscopy experiments predictions from analytical theories. contrast experiments, direct access ionic solvent contributions polarization allows us highlight their significant persistent anticorrelation microscopic origin timescales observed spectrum. This work opens avenues interpretation measurements, offers valuable future developments coarse-grained representations confined electrolytes.