Performance Improvement Of Double-perovskite Anode Sr₂CrMoO_6-? For Solid Oxide Fuel Cells

Solid oxide fuel cell?SOFC?is a device which converts the chemical energy of fuel directly into electrical energy without the information of heat energy.SOFC is one of reliable choices in the future sustainable energy systems because of high energy-efficient and less pollution.The anode materials play a very significant role in SOFC system.This paper we study the performance of the double perovskite Sr₂CrMoO_6-??SCM?as an anode material in SOFC.Subsequently,in order to optimize the performance of SCM,the method of Pd impregnation and Sr²⁺vacancy were used to optimize the properties.SCM was prepared by the sol–gel method.The results of XRD analysis show that SCM exhibit a cubic structure and has good chemical compatibility with LSGM electrolyte after calcined at 1000 ^oC for 10 h.XPS analysis indicates that both Cr and Mo exist with two valence states in SCM sample,including Cr²⁺/Cr³⁺and Mo⁵⁺/Mo⁶⁺ions respecttively.SCM has good thermal stability with LSGM and SDC electrolytes,and the thermal expansion coefficient is 11.7×10^-66 K^-11 at 30–1000?.SCM exhibits semiconducting behavior during the operating temperature.The study of electrochemical properties shows that the polarization assistance can be reduced by Pd-impregnation and forming SCM-Pd composite anodes.With the increase of Pd-impregnation frequency,the polarization impedance decreases first and then increases.The performance of Pd-impregnation is the best when it is impregnated for2 times,and the polarization resistance decrease to 0.5681?cm² at 850?.The maximum power density of single cell reaches 507mW cm^-2.Sr²⁺deficiency double perovskite oxide S_2-xCM?x=0.025,0.050?were prepared by the sol-gel process.S_2-xCM?x=0.025,0.050?show double perovskite structure.The average thermal expansion coefficients of S_2-x-x CM?x=0.025,0.050?are11.2×10^-66 K^-11 and 11.0×10^-66 K^-11 respecctively.S_2-xCM?x=0.025,0.050?have good thermal and chemical compatibilities with LSGM electrolyte as anode material.At 850?,the maximum conductivities of S_2-x-x CM?x=0.025,0.050?are 24.3 S cm^-1?x=0.025?and 34.8 S cm^-1?x=0.050?respecctively.Through introduce Sr²⁺deficiency,the activation energy wasobviously reduced and stability of the material was improved.The study of electrochemical properties shows that the polarization resistancevalues of S_2-xCM?x=0.025,0.050?anodes are 1.4840?cm² and 0.7722?cm²,respectivelythe maximum power density of single cells reaches 385 mW cm^-2and 468 m W cm^-22 at 850?.Sr²⁺deficiency method obviously improves the catalytic activity and the electrochemical performance of the material.