Steady-state, transient and small-amplitude AC responses of an electrochemical cell with immobile background charge: A network approach

The network simulation method has been used to analyse the electrical properties of an electrochemical cell containing two mobile ionic species and immobile background charge in contact with blocking electrodes. The steady-state electrical properties, the transient response of the system to a step-function applied potential difference, and the small-amplitude AC response of the cell have been obtained by simulation in a program for electric circuit analysis of the network modelling the Nernst-Planck and Poisson equations. The electric charge density and the electric potential profiles across the cell were obtained, in the steady state, as a function of the ratio of the initial value of the co-ion concentration to the concentration of immobile background charge. The electrochemical impedance of the system, and the time evolution of the surface charge density stored in the diffuse double layers at the electrode-material interfaces and of the total electric current density through the cell, were also obtained. (C) 2000 Elsevier Science B.V. All rights reserved.