LIU Chulin ¹, MA Ben ¹, ZHOU Yingke ², WU Kaiming ¹
(1. Collaborative Innovation Center for Advanced Steels, Wuhan University of Science and Technology, Wuhan 430081,Hubei, China; 2. The State Key Laboratory of Refractories and Metallurgy, Wuhan University of
Science and Technology, Wuhan 430081, Hubei, China)

Abstract: A Ni doping strategy was used to improve the performance of spinel oxide CuFe₂O₄ cathode material for solid oxide fuel cells (SOFCs). CuFe_2−xNi_xO₄ (x=0, 0.01, 0.03, 0.05, 0.10) powders were prepared by using a sol-gel method. Phase composition, high temperature chemical compatibility with electrolyte, electrical conductivity, thermal expansion coefficient and electrochemical properties of the cathodes in half cell were thematically studied. CuFe_1.95Ni_0.05O₄ exhibited the maximum electrical conductivity and the minimum polarization impedance, with values to be 5.21 S·cm⁻¹ and 2.89 Ω·cm² at 800 ℃, respectively. Both the electrical conductivity and oxygen vacancy concentration could be optimized by controlling the doping concentration of Ni. In this case, the oxygen reduction activity of the material was boosted and the rate determining step in the oxygen reduction process was varied from charge transfer process to oxygen adsorption and dissociation process.
Key words: SOFCs; spinel oxides; cathodes; doping; oxygen reduction reaction