Modeling the impedance spectra of mixed conducting thin films with exposed and embedded current collectors

) is relatively insensitive to the density of triple phase boundaries. As a second step, we studied the configuration where the metal current collector is directly deposited on the ionic conductor and is, therefore, "embedded" into the MIEC. We were again able to reproduce the experimental EIS response. We also discovered that at sufficiently high frequencies, the EIS deviates from a traditional RC-type response, leading to features attributable to the coupling ionic and electronic transport. This coupling ultimately adds to the area specific resistance. The latter, however, can be minimized if the film is sufficiently thick or if the current collector configuration is chosen judiciously.