Performance Of Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-?/Ce_0.85Sm_0.15O_2-?-CuO Composite Cathode For Intermediate Temperature Solid Oxide Fuel Cell

Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3-??BSCF?material has good catalytic activity of oxygen reduction and oxygen ion conduction ability in the range of medium temperature?600?-800??,so it is widely used as cathode material of medium temperature solid oxide fuel cell.In order to improve the performance of BSCF cathode,the experiment is usually to composite the appropriate Ce_0.85Sm_0.15O_2-??SDC?oxygen ion conductor material in the BSCF material to form the BSCF/SDC composite cathode.However,in BSCF/SDC composite cathode materials,the conductivity of SDC is low.If the conductivity of SDC ion can be increased,it will be beneficial to further improve the performance of BSCF/SDC composite cathode.In view of this scientific problem,the method used in this paper is to improve the ionic conductivity of the composite transition metal oxide CuO to SDC,so as to improve the performance of the BSCF/SDC composite cathode.In order to verify the feasibility of this method and explore the optimal sintering temperature of the new cathode,the BSCF/SDC-CuO cathode was sintered at 900?,950?and 1000?.The results of X-ray diffraction show that the crystallinity of BSCF/SDC-CuO powder sintered at three temperatures is good.Compared with BSCF/SDC samples sintered at the same temperature,the X-ray diffraction peak position is similar and no new peak is generated,which indicates that adding CuO will not generate additional impurity phase in BSCF/SDC-CuO samples.The SEM results show that the surface morphology of BSCF/SDC-CuO cathode sintered at three temperatures has porous structure and large surface area,which is conducive to the oxygen reduction reaction.The results of electrochemical performance study show that:in the solid oxide fuel cell with three cathodes of BSCF,BSCF/SDC and BSCF/SDC-CuO,which are based on the same sintering temperature,The polarization impedance of BSCF/SDC-CuO cathode is the lowest,and the highest output power density of its solid oxide fuel cell is the highest.This shows that the idea of adding CuO to improve the ionic conductivity of SDC in BSCF/SDC and then improve the performance of BSCF/SDC composite cathode is feasible.In addition,the polarization impedance of BSCF/SDC-CuO cathode with sintering temperature of 950?is the lowest,and the highest output power density of the solid oxide fuel cell is the highest.It shows that 950?is the best sintering temperature of the new cathode.