Preparion And Performance Reaserch For Metal-supported SOFC

Solid oxide fuel cell?SOFC?is a very competitive green power generation technology.However,the commercialization of SOFC is still hampered by the relatively high manufacturing costs of traditional SOFC materials and the unreliability of the cell packaging process.These significant problems can be solved by reducing the operating temperature of SOFC,when the operating temperature is as low as medium temperature?600-800 oC?or even lower?400-600 oC?,inexpensive stainless steel metal materials can be utilized as the support of SOFC and the connectors of stack.Alternative metal-supported SOFC designs have attracted renewed interest in recent years,driven by their low materials cost,ruggedness and abuse tolerance,and manufacturability benefits.Micro-tubular SOFC have been developed in recent years mainly due to their high specific surface area and fast thermal cycling.Metal-supported micro-tubular solid oxide fuel cell can combine the strengths of metal support and micro-tubular SOFC.A metal support with homogeneous fuel gas channel was prepared by co-casting process or dry pressure process.The mechanical strength of the metal support prepared by co-casting process is improved by adjusting the ratio of pore-forming agent and organic matter in the casting slurry,improving the sintering proc ess,optimizing the pore structure of the metal support.Besides,the sintering characteristics of metal support prepared through dry pressing process are improved by pre-sintering process.In this work,metal supported micro-tubular with double-channel structure is prepared by phase inversion method,which reaches the mechanical strength of 144.72 N,and the effect of spinning pressure and solid content on the morphology of metal micro-tubular is studied.The optimized process parameters are obtained.In contrast to the conventional anode-supported tubular,the mechanical strength of the metal-supported increases 40%.Perovskite Sr_2-xCa_x Fe1.5Mo_0.5O6-? cathodes are synthesized by sol-gel reaction method.The stability of SCFM in reducing atmosphere are excellent when the Ca content x is between 0.1^<sub>0.5.The maximum conductivity of 11.69 S·cm-1 is achieved at 500 oC when the Ca content x is _0.5.The cathode material has a good chemical compatibility with conventional electrolyte materials.The thermal expansion coefficient of the electrode material is reduced by A-site Ca2+ doping.Compared with Sr2Fe1.5Mo_0.5O6-??SFM?,Ca-doped material has better electrochemical performance,the polarization resistance of Sr 1.5Ca_0.5Fe1.5Mo_0.5O6-? decreases to 0.18 ?·cm2 at 750 oC.Also,the excellent thermal stability in oxidizing atmosphere and reducing atmosphere can be achieved by Ca-doped.The SCFM-GDC cathode composites are prepared by physical mixing as to promote the performance of SCFM cathode,and the Rp reaches the minimum of 0.17 ?·cm2 at 750 oC when the content of GDC is 40 wt%.