A numerical study of the equilibrium and nonequilibrium diffuse double layer in electrochemical cells

摘要: A numerical solution of the Nernst-Planck and Poisson equations is presented. The are discretized in a finite difference scheme using method lies on variable spatial temporal grids. Gear’s stiffly stable predictmector integration procedure which automatically adjusts order predictor corrector (and step size) to ensure accuracy results incorporated. Some advantages our approach over more classical ones discussed. applied study equilibrium nonequilibrium diffuse electrical double layer (EDL) at metal electrode/electrolyte interface. prescription this similar that used Gouy-Chapman theory. Electrode kinetics described by Butler-Volmer equation. Concentration, faradaic displacement electric current densities, potential profdea as functions time a- cell thickness, partiahly EDL regions electrode/solution interfaces, obtained. Two physical problems studied: (i) formation EDL, (ii) transient response system an perturbation. Thew examplea illustrate applications method. Numerical techniques for transport electrochemistry have contributed significantly analysis many complex processes difficult deal with conventional approaches. Though other like boundary element experiencing increasing popularity,’ fmite differences2J has been one most widely since pioneering work Feldberg!.s need solutions appears multitude practical interest, e.g., phenomena diffusional type or second-order parabolic PDEs (partial differential equations) subjected conditions,*J diffusion-migration situations involving coupled, nonlinear Nemst-Planck equations,b10 convective diffusion electrochemical cell~,~J etc. Modern cells including effects seem be lacking.’ We present, here, these consisting three ions