High performance La2NiO4+δ impregnated La0.6Sr0.4Co0.2Fe0.8O3-δ cathodes for solid oxide fuel cells

La2NiO4+δ (LNO) impregnated La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathodes were prepared and the effects of the impregnation on the electrical conductivity and oxygen surface exchange property were studied to reveal the enhancement mechanism of oxygen reduction reaction (ORR) catalytic activities. Results of electrochemical impedance spectroscopy (EIS) with distribution of relaxation times (DRT) deconvoluting and electrical conductivity relaxation (ECR) indicate that LNO impregnation into LSCF cathodes enhances the oxygen diffusion process and oxygen surface exchange property. The optimal ORR catalytic activity is achieved after LNO impregnation for two times on the LSCF scaffold (LNO2-LSCF). LNO2-LSCF cathodes also have outstanding performance for their compromise thermal expansion coefficients (TEC) and conductivities. •Proper LNO impregnation enhances the electrochemical performance of LSCF composite cathodes.•LNO impregnation into LSCF cathodes enhances the oxygen surface exchange property.•High performance of LNO impregnated LSCF cathodes is attributed to the advantages of LNO and LSCF.