Distributed relaxation times technique for the determination of fuel cell losses with an equivalent circuit model to identify physicochemical processes

This paper shows the developments of an equivalent circuit model adopted to interpret the deconvoluted electrochemical impedance spectra of an Ni-YSZ/YSZ/GDC/LSCF solid oxide fuel cell obtained by varying the operating temperature and the oxygen partial pressure under a fixed load. This allowed to unfold the physicochemical processes occurring within the anode supported cell and to identify which elements are responsible for major polarization losses. Furthermore, this model has proved to be effective even in the high frequency region, which is often beset by the onset of troublesome artifacts, as underlined by the comparison with the galvanic current interruption technique.