“…[5,12] To improve the Cr tolerance of the cathode for an O-SOFC, a surface modification of electrodes with a rationally designed catalyst coating has been extensively adopted. [1,12,32,33] For example, Sr-free K 2 NiF 4 -type rare-earth nickelate catalyst coating, La 2 NiO 4+δ, [34] Nd 2 NiO 4+δ, and Pr 2 NiO 4+δ, [33] have been considered to be more Cr resistant. In addition, Chen et al reported the better ORR activity and Cr tolerance of LSCF by applying a conformal catalyst coating on the cathode such as BaO, La 0.8 Ca 0.2 FeO 3 , La 0.8 Ca 0.2 Ni 0.4 Fe 0.6 O 3 , Pr 0.75 Ca 0.2 MnO 3 , Pr 0.8 Ca 0.2 FeO 3 , and a hybrid catalyst of PrNi 0.5 Mn 0.5 O 3 and PrO x .…”