Dynamics of electrochemical processes
The dynamic regime of electrochemical processes is on one side dictated by the nature of renewable electricity and on other side it can help in diagnosis of electrochemical systems (like fuel cells and electrolysers) or can influence the productivity of electrochemical reactors (influence catalyst aging, selectivity etc.). Additionally, dynamic methods are invaluable in kinetic mechanism discriminations. EEC group considers methods based on periodic changes of electrical as well as non-electrical inputs. Our current applications are oxygen and CO2 reduction reactions, fuel cells and water electrolysis.
Nonlinear frequency response analysis (NFRA) can be considered as a generalization of the traditional electrochemical impedance spectroscopy (EIS) where instead of small input amplitudes large input amplitudes are used. This drives the system out of a linear range. Therefore, the nonlinear system response contains a linear contribution which corresponds to the electrochemical admittance, as well as nonlinear contributions.
Establishing the hydrogen economy in society is considered by most of the world’s governmental institutions to be one of the main solutions for limiting CO2 emissions. In this scenario, polymer electrolyte membrane fuel cells (PEMFC) represent the principal energy conversion technology used for both mobile and stationary applications.
Successful commercialization of electrochemical systems requires an improvement of their performance, reliability, and durability. In order to
achieve these goals, many studies have been devoted to the development of diagnostic methodologies for the early detection of material degradation symptoms, identification of the causes of degradation mechanisms, and development of mitigation strategies to extend the lifetime of these devices.
Proton exchange membrane water electrolysis (PEMWE) is a key technology for storing excess electrical energy produced by renewable sources in form of hydrogen (Figure 1). To achieve the high productivity of hydrogen, operation at high current density is necessary. However, for this operating
condition, high performance losses appear.