Application of the distribution of relaxation time method in electrochemical analysis of the air electrodes in the SOFC/SOEC devices: A review

Understanding electrochemical sub-processes occurring at solid oxide cells (SOCs) components, mainly air electrodes, is of high importance since they play a key role in improving the performance of SOC devices and their durability. Among various performance analysis methods, electrochemical impedance spectroscopy (EIS) is the most used one in studies. However, analyzing and interpreting EIS data have always been considered as a challenge given the fact that the information provided by the common approach of complex non-linear least square (CNLS) method is limited. Viewed in this sight, the distribution of relaxation time (DRT) approach has gained considerable attention in recent years as a potential approach to analyze EIS measurement results. This study aims at reviewing recent publications that used the DRT method to deconvolute the EIS data and at pathing the way to use DRT methodology and incorporate its results. Studies are focused on six categories of commonly used air electrodes, namely LSCF-based, LSM-based, lanthanide nickelates-based, BSCF-based, and double perovskite-based electrodes, and less-common-used ones.