The Preparation And Properties Research Of Cathode Materials With Spinel Or Perovskite Structure

With the irreversible depletion of fossil fuels,the energy crisis and environmental pollution that humans facing are becoming more and more serious.Solid oxide fuel cells?SOFC?have attracted widespread attention due to their high efficiency and cleanliness.The research of SOFC cathode materials with suitable thermal expansion coefficient?TEC?and excellent electrochemical performance is an important way to promote its development.The spinel structure oxide has a suitable TEC and the perovskite structure oxide has excellent electrochemical performance.In this paper,the series of samples with spinel structure Mn_x Co_3-x-x O₄?x=1,1.25,1.5?,MnCo_2-xCu_xO₄?x=0.2,0.5,1?,Mn_1-xCu_xCo₂O₄?x=0,0.2,0.5?were prepared by the glycine-nitrate process,the perovskite structure ABO_3-??A=Sm?Ba,B=Fe?Co?were prepared by the solid phase reaction method,and explored its feasibility as acathode material for intemidiate temperature solid oxide fuel cell?IT-SOFC?by testing the properties such as its phase structure,TEC,conductivity,electrochemical performance.Mn_xCo_3-xO₄?x=1,1.25,1.5?all formed spinel structure.With the increase of Co,TEC increase,and the interfacial polarization resistance decrease,good single cell output performance.MnCo_2-x-x Cu_xO₄?x=0.2,0.5,1?and Mn_1-xCu_xCo₂O₄?x=0,0.2,0.5?all formed cubic spinel structure.With the appropriate doping of Cu,the average TEC and the conductivity of the samples all increases,the electrochemical catalytic activity becomes better.The maximum output power density of MnCo_1.5Cu_0.5O₄ and Mn_0.5Cu_0.5Co₂O₄ at 800°C is 391,477 m W cm^-2,respectively.The samples of ABO_3-??A=Sm?Ba,B=Fe?Co?all formed pure perovskite structure and were chemically compatible with the La_0.9Sr_0.1Ga_0.8Mg_0.2O_3-??LSGM?electrolyte.Co doping causes the average TEC and the conductivity increases,the catalytic activity increases.The single cell output power density reaches 466 m W cm^-22 at 800°C.The results of the study indicate that the four series of samples can be used as IT-SOFC cathode materials,the higher impedance of spinel cathode material can be improved by doping the ion phase and preparing the composite cathode.