Research Of Cathode Materials La-Ni-M-O₃(M=Fe, Cu) For Intermediate Low Temperature Solid Oxide Fuel Cell

Solid oxide Fuel cell is a kind of electricity-generating device which can transform the chemical energy of fuel into electricity directly through the electrochemical reaction. For the traditional SOFC,the operation temperature is generally in a relative higher temperature range of 800-1000℃,which bring up a lot of problems,such as the materials selection,the manufacture cost,life time,etc..Therefore,the most urgent problem confronted presently with us was how to lower down the operating temperature of SOFC,especially the cathode of SOFC,and make the commercialization of intermediate low temperature SOFCs(ILTSOFCs)come true.The solid oxide with perovskite structure has been considered as the promising cathode materials for ILTSOFCs application.In order to develop the new cathode materials with perovskite structure suitable for ILTSOFCs,LaNi_l-xFe_xO₃(x=0.4-0.8) (LNF)and LaNi_0.2Fe_0.8-xCu_xO₃(x=0.0-0.2)(LNFC)powders are prepared using coprecipitation method on the basis of La-Ni-O3.The structure and morphology of the synthesized powders are characterized by the test of electrical conductivity and X-ray diffraction(XRD).Fuel cells are fabricated to evaluate the electrochemical properties of the LNF and LNFC materials as cathodes at different operating temperatures.The peak power density of the fuel cell with LaNi_0.2Fe_0.65Cu_0.15O₃ cathode reaches 635.2mW/cm² and 762.7mW/cm² at 580℃and 650℃respectively,which are much higher than that of LaNi_0.2Fe_0.8O₃ in the same condition.The results indicate those copper doped materials have higher electrochemical performance compared with undoped materials. LaNi_0.8Cu_0.2O₃(LNC-82)is synthesized using coprecipitation method.Its electrochemical performance also has been tested.The peak power density of the fuel cell with LNC-82 cathode reaches 620mW·cm^-2at 450℃,which is much higher than that of LaNi₍l-x_Cu_xO₃ (x=0.2-0.7)in the same condition and which is close to the value of LaNi_0.2Fe_0.65Cu_0.15O₃ cathode at 580℃.So LaNi_0.8Cu_0.2O₃ is a very promising cathode for ILTSOFCs.