Charge relaxation dynamics of an electrolytic nanocapacitor
| Autor: | Vaibhav Thakore, James J. Hickman |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Materials science
Lattice Boltzmann methods FOS: Physical sciences 02 engineering and technology Thermal diffusivity 7. Clean energy 01 natural sciences Capacitance Article Ion Solution of Schrödinger equation for a step potential Electric field Physics - Chemical Physics 0103 physical sciences Physical and Theoretical Chemistry 010306 general physics Chemical Physics (physics.chem-ph) Relaxation (NMR) Fluid Dynamics (physics.flu-dyn) Physics - Fluid Dynamics Computational Physics (physics.comp-ph) 021001 nanoscience & nanotechnology Surfaces Coatings and Films Electronic Optical and Magnetic Materials General Energy Chemical physics 0210 nano-technology Current density Physics - Computational Physics |
| Zdroj: | The Journal of Physical Chemistry. C, Nanomaterials and Interfaces |
| Popis: | Understanding ion relaxation dynamics in overlapping electric double layers (EDLs) is critical for the development of efficient nanotechnology based electrochemical energy storage, electrochemomechanical energy conversion and bioelectrochemical sensing devices as well as controlled synthesis of nanostructured materials. Here, a Lattice Boltzmann (LB) method is employed to simulate an electrolytic nanocapacitor subjected to a step potential at t = 0 for various degrees of EDL overlap, solvent viscosities, ratios of cation to anion diffusivity and electrode separations. The use of a novel, continuously varying and Galilean invariant, molecular speed dependent relaxation time (MSDRT) with the LB equation recovers a correct microscopic description of the molecular collision phenomena and enhances the stability of the LB algorithm. Results for large EDL overlaps indicated oscillatory behavior for the ionic current density in contrast to monotonic relaxation to equilibrium for low EDL overlaps. Further, at low solvent viscosities and large EDL overlaps, anomalous plasma-like spatial oscillations of the electric field were observed that appeared to be purely an effect of nanoscale confinement. Employing MSDRT in our simulations enabled a modeling of the fundamental physics of the transient charge relaxation dynamics in electrochemical systems operating away from equilibrium wherein Nernst-Einstein relation is known to be violated. Accepted for publication in the Journal of Physical Chemistry C on October 30 2014. Supplementary info available free of charge via the Internet at http://pubs.acs.org. Revised version includes more details on the computation of the molecular speed dependent relaxation time (MSDRT) and emphasizes the Galilean invariance of the computed MSDRT |
| Databáze: | OpenAIRE |
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