Effects of cerium doping on the performance of LSCF cathodes for intermediate temperature solid oxide fuel cells

In this paper, effects of Ce substitution of La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) on the crystal structure have been investigated by XRD Rietveld refinement and results show that Ce doping at La-sites leads to lattice expansion without changing centrosymmetric cubic space group of LSCF. The electrochemical results suggest that the electrocatalytic activity of LSCF cathodes is enhanced by Ce doping. The values of oxygen surface exchange coefficient of LSCF, LCSCF03, LCSCF06, measured by electrical conductivity relaxation (ECR) method, are 5.6 × 10−4 cm s−1, 1.0 × 10−3 cm s−1, 3 × 10−3 cm s−1 at 750 °C respectively, implying that oxygen surface exchange coefficients are increased by Ce doping compared with that of LSCF. The enhancement of electrochemical performance of LSCF cathodes can be ascribed to the increase of the concentration of oxygen vacancies obtained from the thermogravimetric results, which results in faster kinetics of oxygen transport by Ce doping.