Influence of Micrometric-Scale Electrode Heterogeneity on Electrochemical Impedance Spectroscopy
Résumé
Numerical simulationsforadiskelectrodeshowthatthefrequencyatwhichtime–constantdispersion
appears dependsonthecharacteristicdimensionofthefeaturecausingthedispersion.Thecharacter-
istic dimensionforadiskistheradius;forroughness,itisafunctionofrugosityandtheperiodof
the roughness;andforacapacitancedistribution,itistheperiodofthedistribution.Distributionsof
charge–transfer resistancedonotcausetime–constantdispersionbecausetheyinfluenceneitherthe
ohmic resistancenorthecapacitance.Asonlythehigh–frequencyimpedanceisaffectedbyroughness
and capacitydistributionsandcharge–transferresistancedistributionsdonotcausefrequencydisper-
sion, surfaceheterogeneityintheformofroughness,capacitance,orcharge–transferresistancecannot
provide anexplanationforCPEbehaviorassociatedwithsurfacedistributions.