Abstract:

Electrochemical impedance spectroscopy (EIS) is a widely used electrcochemical technique for investigation of batteries, fuel cells but also solar cells and similar electrochemical devices. The common denominator of these devices is that the active material in question is used in a nanostructured form. This inevitably leads to the construction and usage of so-called porous electrodes. The latter, however, may present a challenge for interpretation of experimentally obtained impedance spectra. Namely, it is well known – since the original Newman’s porous electrode model published more than 50 years ago – that the physics of the transport and reaction in porous electrodes may be rather complex. However, we show that for some cases of interest there exist simplified approaches that lead to quite accurate physics-based analysis of the corresponding impedance response. In the case of batteries, we will show experimental-theoretical examples of the use of the so-called transmission lines on state-of-the-art cathode and anode materials. By contrast, in the case of electrocatalysts we will focus on the burning question of how to determine the real active surface area of a non-metallic catalyst when used in a porous electrode configuration. In this context, the recent suggestions from the literature will be critically revisited and an upgraded approach presented and discussed.

Short Biography of the Speaker:

Dr. Miran Gaberšček, Professor of Materials Science is Head of Department for Materials Chemistry at the National Institute of Chemistry, Ljubljana, Slovenia. He is also affiliated to the University of Ljubljana. His primary research field has been electrochemical systems for energy storage and conversion (batteries, fuel cells). His main focus has been the explanation of complex charge transport and reaction mechanisms using impedance spectroscopy. Prof. Gaberšček has published about 250 papers, some of them in prestigious journals such as Nature Materials, Advanced Materials, Angewandte Chemie. JACS and similar.