Preparation And Performance Of Layered Perovskite Cathode Materials PBCMx(m=Cu,Fe) For Intermediate-tempearture Solid Oxide Fuel Cells

With the rapid devolopement of science technology,the global energy crisis andthe extrusive environmental pollution make the point of researching novelenvironment-protecting and energy-saving materials.So far,among the ways ofenergy-transforming that invented,SOFC has the highest transformationefficency,which is a environment-friendly energy-storing device,a kind of H₂, CO andhydrocarbons such as fuel.The cathode plays a vital role in the whole cell outputperformance,so it’s very important to research and devolop high performance SOFCscathode materials.The double pervoskites cathode with the ordered structures types in the Asites,due to its rapid oxyen ion diffusion,surface exchange kinetic and highconductivty,has been applied in SOFCs,becoming one of the promising cathodematerials.In usual conditions,the large TEC of Cobalt-materials directly influence theheat circulation progress between the cathode and electrolyte,thereby decreasing theoutput performance of cell.In order to increasing the compability of the cathode andelectrolyte,usually in use of doping Fe,Cu etl. Transition metal elements decreasingthe TEC.In this paper,two kinds of MIEC cathode double pervoskites PBCC,PBCF areresearched about the structure,the compability with the electrolye,the electrochemicalperformance etl.The influence of Cu-doping content to the electrochemical performance isinvestigated in the Chaper3. The PrBaCo_2-xCu_xO_5+δcathode materials wassynthesis via citric acid method,10hours after900℃burning,thenformed orthogonal states of calcium mineral structure. When the Cu content thesame, as the temperature rises, the conductivity decreased, in the sametemperature under certain conditions, with the content of Cu increased, theconductivity first increased,then decreased.The TEC of PBCCx decreased with thethe content of Cu increasing. With the content of Cu increased in the cathode polarization resistance interface （RP） first decreases and then increases, whenthe content of Cu x is1.0, the minimum value of RP, in the600℃,650℃,700℃,750℃and800℃is0.768，0.23393，0.10827，0.0638å'Œ0.04447cm2. Battery powerdensity increases with Cu content, decreases at first and then increases, when theCu content x is0.5, the single cell shows the best electrochemical performance,with Ni0.9Cu0.1-SDC as the anode, SDC as the electrolyte, the maximum outputpower density of the electrolyte-support single cell at600℃,650℃,700℃,750℃,and800℃is139.88,246.86,363.23,465.24å'Œ532.91mW/cm2.The influence of Fe-doping content to the electrochemical performance isinvestigated in the Chaper4. The PrBaCo_2-xFe_xO_5+δcathode materials wassynthesis via citric acid method,10hours after950℃burning,materials havebeen formed orthogonal states of calcium mineral structure. As the Fe content of thesame, as the temperature rises, the conductivity decreased, in the sametemperature under certain conditions, with the Fe content increased, the conductivitydecreased. The TEC of PBCFx decreased with the the content of Fe increasing.When the content of Fe is2.0,the TEC is13.39×10^-6K^-1that is close to SDC which is12.02×10^-6K^-1. With the increase of Fe content in the cathode materials,thepolarization resistance interface （RP） decreased.When the content of Fe is1.0,RPvalue of the minimum, in the600℃,650℃,700℃,750℃and800℃when theinterface The value of the corresponding RPis0.95957，0.33645，0.14889，0.08121，0.04222cm2. Battery power density increases with Fe content.The beginning point in this paper is to decrease the TEC of the materials toimprove the performance,after a systematic study, the experimental results goes well.