Abstract
The Distribution of Relaxation Times (DRT) was successfully demonstrated in the analysis of the impedance spectra of a parametric series of composite polyaniline (PANI) coated carbon nanotubes (CNT) electrodes. DRT was then applied to the measured spectra and polarization processes were separated based on their typical time constants. The main processes were identified, and their contribution quantified by analysing a set of electrodes with PANI deposited under various conditions, forming a parametric set. For the first time we have shown that DRT can be used to identify individual internal processes of complex composite electrodes without a priori knowledge of the system. This method offers a model-free approach for the study of EIS spectra and the characterization of resistive-capacitive systems. This was demonstrated by the optimisation of our PANI coated CNT electrodes which have exhibited a PANI specific capacitance of 772 F g − 1 and rate capability of 76% from 1 to 100 mV s − 1.