Experimental verification of pore impedance theory: Drilled graphite electrodes with gradually more complex pore size distribution

Abstract

In this work, electrochemical impedance spectroscopy (EIS) measurements were carried out on increasingly complex distribution of cylindrical pores with well-defined geometries. The complexity of the system was increased by stepping up from a single pore to multiple pores with uniform pore depth and radii followed by generating pore size distributions. The impedance response was interpreted using ZView fitting and a graphical approach and was found to be well-described by existing theory. We characterised the impedance response of the resulting porous electrodes with varying geometrical and electrochemical parameters - pore depth, pore radii, pore density, and electrolyte conductivity. The obtained results suggest a possibility to use measurements on drilled cylindrical pores to interpret more complex pore size distributions (PSDs) as measurements of PSDs were successfully modelled by adding the impedance response of single pores.