In my opinion, although the authors have made a significant effort., there is still more room for further improvements to make the paper much more attractive for the JMCA journal and their readers.
Both referees were asking for addition measurements on SOFC, SOEC, DC conductivity and also experiments as a function of pO2. However, one just out of four experiments was completed (SOFC characterization) and in my opinion the paper would be significantly improved with more data, especially seeing that the SOFC characterization is positive. Maybe the experiments as a function of pO2 could be out of scope, but at least SOEC (currently being carried out) and DC conductivity measurements should be included before acceptance.