Electrochemical impedance spectroscopy of porous electrodes: the effect ofpore size distribution

A new model for the impedance of porous materials was developed. The transm ission line model with pore size distribution (TLM-PSD) is based on the tra nsmission line equivalent circuit, considering the effect of pore size dist ribution (PSD). The PSD was represented by an analytical distribution funct ion, for example, the log normal distribution, With this model, impedance w as a sole function of the representative penetrability alpha(mu) when the s tandard deviation a is constant. Phase angle at low frequency or high penet rability changes from -90 degrees at sigma = 0 to -45 degrees at sigma = in finity. This indicates that a wider distribution leads to more porous chara cteristics of impedance. Experimental impedance data of a gold powder elect rode were successfully fitted with the TLM-PSD, (C) 1999 Elsevier Science L td. All rights reserved.