Convection can enhance the capacitive charging of porous electrodes

Fuente: arXiv
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Main Authors: Ratschow, Aaron D., Wagner, Alexander J., Janssen, Mathijs, Hardt, Steffen
Format: Preprint
Published: 2024
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author Ratschow, Aaron D.
Wagner, Alexander J.
Janssen, Mathijs
Hardt, Steffen
author_facet Ratschow, Aaron D.
Wagner, Alexander J.
Janssen, Mathijs
Hardt, Steffen
contents Charge transport in porous electrodes is foundational for modern energy storage technologies like supercapacitors, fuel cells, and batteries. Supercapacitors in particular rely solely on storing energy in charged pores. Here, we simulate the charging of a single electrolyte-filled pore using the modified Poisson-Nernst-Planck and Navier-Stokes equations. We find that electroconvection can substantially speed up the charging dynamics. We uncover the fundamental mechanism of electroconvection during pore charging through an analytical model that predicts the induced flow field and the electric current arising due to convection. Our findings suggest that convection is especially important in the limit of slender pores with thin electric double layers, and becomes significant beyond a certain threshold voltage that is an inherent electrolyte property.
format Preprint
id arxiv_https___arxiv_org_abs_2410_12653
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Convection can enhance the capacitive charging of porous electrodes
Ratschow, Aaron D.
Wagner, Alexander J.
Janssen, Mathijs
Hardt, Steffen
Soft Condensed Matter
Fluid Dynamics
Charge transport in porous electrodes is foundational for modern energy storage technologies like supercapacitors, fuel cells, and batteries. Supercapacitors in particular rely solely on storing energy in charged pores. Here, we simulate the charging of a single electrolyte-filled pore using the modified Poisson-Nernst-Planck and Navier-Stokes equations. We find that electroconvection can substantially speed up the charging dynamics. We uncover the fundamental mechanism of electroconvection during pore charging through an analytical model that predicts the induced flow field and the electric current arising due to convection. Our findings suggest that convection is especially important in the limit of slender pores with thin electric double layers, and becomes significant beyond a certain threshold voltage that is an inherent electrolyte property.
title Convection can enhance the capacitive charging of porous electrodes
topic Soft Condensed Matter
Fluid Dynamics
url https://arxiv.org/abs/2410.12653