Alkaline-earth-free quasi-ternary La(Co, Ni, Fe)O3−δ perovskite as potential cathode for solid oxide fuel cells

The purpose is to develop alternative alkaline-earth-free quasi-ternary LaCoO3−LaNiO3−LaFeO3 cathode materials for solid oxide fuel cells (SOFCs), which demonstrate high electrical conductivity, good electrochemical performance and excellent chemical stability against CrO2(OH)2 released from the metallic interconnects at operation temperatures. Three different perovskites of lanthanum in combination with iron, cobalt and nickel oxides, i.e. LaFe0.8Co0.1Ni0.1O3−δ (LFCN), LaNi0.8Co0.1Fe0.1O3−δ (LNCF) and LaCo0.8Fe0.1Ni0.1O3−δ (LCFN), were synthesized by the modified Pechini method, and then systematically investigated in the phase structure, thermal expansion, electrical conductivity and catalytic activity. LFCN have the best combination to the requirements of high-performance cathodes for SOFCs. Button cells with LFCN cathode were prepared on anode-supported YSZ electrolyte with gadolinium-doped cerium (GDC) buffer layer by screen printing. Excellent electrochemical performance with high maximum power density of 643 mW.cm−2 at 750 °C and corresponding low polarization resistance of 0.62 Ω cm2 further demonstrate that LFCN is a very competitive candidate as SOFC cathode.