Electrochemical characterisation of macroporous electrodes: Recent advances and hidden pitfalls

Investigating the intrinsic kinetics of macroporous electrodes by means of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) is an exceptionally challenging task with a multitude of hidden pitfalls. The classical analysis (e.g. the Randles–Ševčík or the Nicholson methods) cannot be used for macroporous electrodes as these can only be applied to electrodes which exhibit mass transport controlled by planar semi-infinite diffusion and that have spatially uniform redox activity. Unfortunately, a number of recent articles incorrectly interprete data by applying classical analysis to macroporous electrodes. To address this, the CV and EIS analysis methods, which can be used for macroporous electrodes are reviewed and discussed.