English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Porous electrodes are found in energy storage devices such as supercapacitorsand pseudocapacitors. However, the effect of electrode-pore-size distributionover their energy storage properties remains unclear. Here, we develop a modelfor the charging of electrical double layers inside a cylindrical pore forarbitrary pore size. We assume small applied potentials and perform a regularperturbation analysis to predict the evolution of electrical potential and ionconcentrations in both the radial and axial directions. We validate ourperturbation model with direct numerical simulations of thePoisson-Nernst-Planck equations, and obtain quantitative agreement between thetwo approaches for small and moderate potentials. Our analysis yields two maincharacteristic features of arbitrary pore size: i) a monotonic decrease of thecharging timescale with an increase in relative pore size (pore size relativeto Debye length); ii) large potential changes for overlapping double layers ina thin transition region, which we approximate mathematically by a jumpdiscontinuity. We quantify the contributions of electromigration and chargediffusion fluxes which provide mechanistic insights into the dependence ofcharging timescale and capacitance on pore size. We develop a modifiedtransmission circuit model that captures the effect of arbitrary pore size anddemonstrate that a time-dependent transition-region resistor needs to beincluded in the circuit. We also derive phenomenological expressions foraverage effective capacitance and charging timescale as a function of pore-sizedistribution. We show that the capacitance and charging timescale increase withsmaller average pore sizes and with smaller polydispersity, resulting in a gainof energy density at a constant power density. Overall, our results advance themechanistic understanding of electrical-double-layer charging.

Charging Dynamics of Electrical Double Layers Inside a Cylindrical Pore: Predicting the Effects of Arbitrary Pore Size