Surface modification of La0.6Sr0.4Co0.2Fe0.8O3 cathode by infiltrating A-site deficient non-strontium La0.94Ni0.6Fe0.4O3 perovskite for solid oxide fuel cells

La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) is a promising cathode for intermediate temperature range, however strontium tends to segregate on the surface of the cathode and reacts with CO2 from atmosphere and Cr from interconnect, which deteriorates its oxygen reduction reaction (ORR) activity. Here, we propose infiltrating stable and active A-site deficient Fe-doped lanthanum nickelate perovskite La1-xNiyFe1-yO3 without Sr element over the LSCF by delicately tailoring the infiltrating amount. It is found that 150 mu L La0.94Ni0.6Fe0.4O3(LNF94) infiltrated LSCF (LNF94@LSCF) composite cathode with improved ORR catalytic activity, its polarization resistance is 0.041 O center dot cm2 and peak power densities of 1.08 W cm-2 is obtained from the single cell with LNF94@LSCF composite cathode at 800 degrees C. The heterogeneous interface significantly improved the electron conduction and enhanced the dissociation of oxygen molecules which has been verified by the energy band alignment of LSCF and LNF94. Moreover, the core-shell LNF94@LSCF composite cathode showed excellent long-term tolerance to CO2 and Cr atmosphere.