Computational Amperometry of Nanoscale Capacitors in Molecular Simulations

Abstract

In recent years, constant applied potential molecular dynamics has allowed to study the structure and dynamics of the electrochemical double-layer of a large variety of nanoscale capacitors. Nevertheless it remained impossible to simulate polarized electrodes at fixed total charge. Here we show that combining a constant potential electrode with a finite electric displacement fills this gap by allowing to simulate open circuit conditions. The method can be extended by applying an electric displacement ramp to perform computational amperometry experiments at different current intensities. As in experiments, the full capacitance of the system is obtained at low intensity, but this quantity decreases when the applied ramp becomes too fast with respect to the microscopic dynamics of the liquid.

arXiv comment17 pages, 7 figures

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Cited by in corpus (5)

• ELECTRODE: An electrochemistry package for atomistic simulations
• Constant Potential and Constrained Charge Ensembles for Simulations of Conductive Electrodes
• Frequency-dependent impedance of nanocapacitors from electrode charge fluctuations as a probe of electrolyte dynamics
• A theory for the stabilization of polar crystal surfaces by a liquid environment
• Fully Periodic, Computationally Efficient Constant Potential Molecular Dynamics Simulations of Ionic Liquid Supercapacitors