Performance Of LnBaFe₂O_5+?-based?Ln=Pr,Nd? Double Perovskites As Anode Materials For Solid Oxide Fuel Cells

The fuel cell is the fourth power generation technology after hydroelectric power generation,thermal power generation and atomic power generation.It is an energy conversion device that directly converts chemical energy in fuel into electrical energy.The solid oxide fuel cell?SOFC?has attracted much attention because of its solid electrolytes and the flexibility of fuels.The main challenge of SOFCs is the potential for carbon deposition and sulfur poisoning on the anode when using hydrocarbons as fuels.Therefore,it has become a top priority to develop new anti-carbon and sulfur-resistant poisoning anode materials.Based on this,A-site ordered double perovskite LnBaFe₂O_5+??LnBFO??Ln=Pr,Nd?series materials were studied,and their feasibility as SOFC anode materials was discussed in this work.The tetragonal LnBFO?Ln=Pr,Nd?anode materials were obtained by sol-gel method.The materials had good chemical compatibility with the commonly used electrolytes LSGM and SDC.NdBaFe₂O_5+??NBFO?demonstrated the best electrical properties,and achieved the conductivity of 31.2 S cm^-11 at 850?.The maximum power density of the cell with NBFO|SDC|LSGM|NBCFC component can reach up to1242 mW cm^-22 in hydrogen,which is much higher than the performance of most anode materials.And the single cell exhibited a very stable performance at 750? in methane for 100 hours without obvious degradation,indicating that the NBFO anode has excellent redox stability and is a very promising SOFC anode material.A-site defective double perovskite oxide NdBa_1-xFe₂O_5+??x=0.02,0.04,0.06?were prepared to further improve the electrochemical performance of NBFO anode.It showed that the electrochemical impedance was reduced by 44%at 850? at x=0.02compared to the NBFO anode.The maximum power densities of the cells were increased by 11%,9%,and 12%when using hydrogen,syngas,and methane as fuels,respectively.It demonstrated that the introduction of A-site deficiency into NBFO can effectively improve the electrochemical impedance and cell performance.