(Bi0.15La0.27Sr0.53)(Co0.25Fe0.75)O3-δ perovskite: A novel cathode material for intermediate temperature solid oxide fuel cells

Perovskite oxides (Bi0.15La0.27Sr0.53)(x)(Co0.25Fe0.75)O3-delta (BiLSCFx, x = 0.8, 0.9, 1.0,11) have been synthesized by solid state reaction and evaluated as a novel cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The effects of A-site variations on lattice structure, calcination temperature, oxygen desorption and electrochemical properties of BiLSCFx are investigated. This kind of material has perfectly cubic structure based on the Pm-3m space group whose lattice size increases with x, which is thermally stable after calcination and shows desirable chemical compatibility with La0.8Sr0.2Ga0.8Mg0.2O3-delta electrolyte at 1150 degrees C for 8 h under air atmosphere. Among those A-site variations, it is found that BiLSCF0.9 demonstrates the best cathode performance. It has the minimum polarization resistance value of 0.039 Omega cm(2) at 700 degrees C and alpha-oxygen desorbed about 0.031 mmol g(-1), indicating a good reactivity and strong adsorbate of O-2. The single cell with BiLSCF0.9 cathode delivers a power density of 0.66 W cm(-2) at 700 degrees C with humidified H-2 (similar to 3% H2O) as the fuel and ambient air as the oxidant. In addition, the cell shows sufficient stability with similar to 9% degradation over 75 h at 600 degrees C. It indicates that BiLSCF0.9 is a promising candidate for application as cathode material in IT-SOFCs. (C) 2016 Elsevier B.V. All rights reserved.