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Cobalt-Bansed Ca3Co2O6-δ Cathode And Composite Cathode Materials Preparation And Performance Evaluation

Posted on:2016-05-07Degree:MasterType:Thesis
Country:ChinaCandidate:Y J WangFull Text:PDF
GTID:2191330461482246Subject:Physical Electronics
Abstract/Summary:PDF Full Text Request
In order to solve the problem of environment pollution and energy crisis, it is necessary for social development to seek efficient, clean pollution-free renewable energy. Solid Oxide Fuel Cells (SOFCs) received extensive attention all over the world due to their high energy conversion efficiency and environmental friendliness.Cathode is one of the key components to realize intermediate temperature solid oxide fuel cells (IT-SOFCs).Therefore,this paper focuses on IT-SOFC as a starting point. We study the phase constitution,microstructure and electrochemical performance of Ca3Co2O6-δ cathode.On this basis,we add the right amount of electrolyte in cathode to improve its performance.The related research is whether the composite cathode can be used as cathode material.Ca3Co2O6-δ cathode materials is synthesized by the method of sol-gel in this paper. XRD results show that Ca3Co2O6-δ cathode powder formed the close packing of perovskite structure which is sintered in 850℃.The conductivity of Ca3Co2O6-δ is 9.55S cm-1 in 800℃. The polarization resistance of Ca3Co2O6-δ cathode is 0.427 Ω.cm2 in 800℃.The power density of electrolyte-supported single cell with Ca3Co2O6-δ as cathode is 394.1 mWcm’2, and the power density of anode-supported single cell is 307.26 mWcm-2in 800℃.In order to expand the cathode, electrolyte and air three-phase interface and improve the catalytic activity of oxygen,We put Ca3Co2O6-δ cathode and SNDC electrolyte composite together by using the mechanical synthesis in this paper and we get composite cathode Ca3Co2O6-δ-xSNDC (x= 0 to 50 wt%).XRD results show that Ca3Co2O6-δ and SNDC did not occur chemical reaction after Ca3Co2O6-δ-50SNDC composite cathode being sintered in 900℃.We can know that it has a good chemical compatibility between Ca3Co2O6-δ and SNDC.SEM results showed that the voidage of composite cathode is uniform after being sintered and it has formed a good three-dimensional network structure.The polarization resistance of Ca3Co2O6-δ-30SNDC composite cathod is 0.28 Ω.cm2 in 800℃.Compared with Ca3Co2O6-δ cathode(0.427 Ω. cm2), the polarization resistance reduced 0.147 Ω.cm2in 800℃.The power density of anode-supported single cell with Ca3Co2O6-δ-30SNDC composite materials as cathode is 406.28 mWcm-2.Compared with Ca3Co2O6-δ cathode, power density increased 99.02 mWcm-2.In conclusion,if the process is optimized,Ca3Co2O6-δ material and composite material may be become potential cathode materials of IT-SOFC.
Keywords/Search Tags:SOFC, Ca3Co2O6-δ, composite cathode, electrochemical performance
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