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

The energy level of La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 is matched with that of La 0.94 Ni 0.6 Fe 0.4 O 3 (LNF94), and the electron conductivity of LNF94 is higher, which can accelerate the electron transport capacity of the composite cathode and the dissociation and adsorption of oxygen molecules on the surface. • LNF94 infiltrated LSCF composite cathode with improved ORR catalytic activity. • The construction of heterogeneous interface of LNF94 and LSCF can significantly improve electron conduction. • The infiltration of LNF94 demonstrated that shell materials can suppress Sr segregation and higher CO 2 and Cr tolerance. La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF) is a promising cathode for intermediate temperature range, however strontium tends to segregate on the surface of the cathode and reacts with CO 2 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 La 1-x Ni y Fe 1-y O 3 without Sr element over the LSCF by delicately tailoring the infiltrating amount. It is found that 150 μL La 0.94 Ni 0.6 Fe 0.4 O 3 (LNF94) infiltrated LSCF (LNF94@LSCF) composite cathode with improved ORR catalytic activity, its polarization resistance is 0.041 Ω·cm 2 and peak power densities of 1.08 W cm - 2 is obtained from the single cell with LNF94@LSCF composite cathode at 800 °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 CO 2 and Cr atmosphere.