Performance Of Double Perovskite Cathode Materials LaBaCo₂O_5+σ For Intermediate-temperature Solid Oxide Fuel Cells

Energy is the development of the whole world, the basic driving force ofeconomic growth in the country, is the basis for human survival anddevelopment.21st century is the era of rapid economic development, alongwith the increasing demand for energy and increasing depletion ofconventional fossil fuels, we are facing a severe test of energy. Therefore newclean, renewable energy is increasingly becoming the focus of attention. Fuelcell (SOFC) is a very promising type of efficient and clean energy conversiondevice, its high energy conversion efficiency, environmentally friendly and doesnot emit harmful gases, so the fuel cell battery in the new century to becomeone of the most promising.The cathode is another important part of the solid oxide fuel cell, also calledair cathode electrode, the cathode material is good or bad a direct impact onthe performance of a single cell. In recent years, A bit ordered perovskitestructure attracted attention, studies have shown that the A bit orderedperovskite structure is conducive to the transport of oxygen ions, which canpromote the proliferation of O2-, and can increase the surface activity of thereaction. Such ordered perovskite structure cathode materials are widely usedin the solid oxide fuel cell, has become one of the most promising cathodematerial. A bit is a simple perovskite arranged in random distribution, anddouble perovskite structure is highly ordered distributionLn3+and Ba2+orderly arrangement and form ordered alternating layersalong the c-axis. Double perovskite material LaBaCo2O5+δhas been shown tohave good electrochemical performance, but because of a cobalt-basedmaterial generally has a larger thermal expansion coefficient (TEC), which compared with the conventional electrolyte large gap, so that the cathodematerial good thermal matching properties of the electrolyte material, so thatthe power density of the battery are greatly reduced. In order to find a moresuitable temperature solid oxide fuel cell (IT-SOFC) cathode material, weLaBaCo2O5+δ-based materials, a doped alternative method Sr and Ba, tostudy it as IT-SOFC cathode material possibilities.In this paper, the doubleperovskite cathode material LaBa1-xSrxCoO5+δ(x=0.0,0.25,0.5,0.75,1.0)structure, morphology, electrical conductivity, the degree of mapping with theelectrolyte, and electrochemical properties. Results LaBa0.75Sr0.25CoO5+δcathode material exhibits excellent performance cathode, after further studyLaBa0.75Sr0.25CoO5+δ-Ce0.85Sm0.15O1.9performance composite cathode, thecomposite fine IT-SOFC system as the cathode, a feasibility study.LaBa1-xSrxCo2O5+δthis paper EDTA-citrate sol-gel method cathode materialLaBa1-xSrxCo2O5+δ(LB1-xSxCO, x=0.0,0.25,0.5,0.75,1.0), after1000℃sintered10hours after XRD results indicate that the formation of materialsingle phase layered perovskite structure. In the30-850o C temperaturerange, the average sample LaBa0.75Sr0.25CoO5+δfor TEC. In the600-800oCtemperature envelope, the conductivity of the sample LaBa0.75Sr0.25Co2O5+δ425-619Scm-1.800o C when LaBa0.75Sr0.25Co2O5+δcathode on SDCelectrolyte polarization resistance is0.04651Ω cm2.800o C whenLaBa0.75Sr0.25Co2O5+δas the cathode and the anode Ni0.9Cu0.1-SDC, SDCsingle cell electrolyte, the power density of480.27mW/cm2.omposite cathode one can expand the cathode, electrolyte and air-phaseinterface that allows the cathode oxygen reduction reaction zone spread to theentire surface of the cathode; hand also can improve the microstructure andelectrolyte interfacial thermal matching of its junction with the purchase, is acombination of both better, and reduce its cathodic polarization Congresistance, improved electrochemical performance. Based on the aboveconsiderations, we SDC cathode and electrolyte materials LBSC differentmass ratio were mixed to make a composite cathode is desirable in order to further improve the performance of the cathode material LBSC to meet therequirements of IT-SOFC cathode material.This paper studies the SDC electrolyte and cathode LB0.75S0.25C conductedby the ratio of the composite formed LBSC-xSDC (x=0-50) compositecathode materials. LBSC-50SDC composite cathode has the smallest TEC, inthe30-850oC temperature range, the average TEC is15.255×10-6K-1.LBSC-xSDC conductive composite cathode SDC amount increases graduallydecreased. Join SDC in the cathode electrolyte, the electrochemicalproperties of the composite cathode significantly improved. Wherein thecomposite cathode LBSC-30SDC cathode material exhibited the bestperformance,800oC, the polarization resistance of the composite cathode is0.02437cm2.800o C when LBSC-30SDC as the cathode and isNi0.9Cu0.1-SDC anode electrolyte SDC maximum power density of single cellswere reached545.75mW cm-2. Based on the above experimental resultsshow that the cathode may be regarded as a potential IT-SOFC cathodematerial.