Preparation And Characterization Of Composite Electrolyte Ce_0.8Gd_0.2O_1.9-Borate For Solid Oxide Fule Cell

Solid oxide fuel cell(SOFC)has been more and more concerned by researchers,as a highly efficient conversion and green energy devices.The stability of single battery components fell and the cost of materials are higher under high temperature.As the core component of SOFC,the performance of electrolyte directly affects the output power of the cell.It is necessary to developing the electrolyte with high conductivity in the intermediate temperature.In this study,a novel composite electrolyte of Gd0.20Ce0.80O1.90(GDC)-Na234O7(NBO)was investigated in order to increase the total conductivity in medium operating temperature.GDC-NBO composite powders(molar ratio 8:2)were synthesized via citric acide-nitrate gel combustion method and mechanically-mixing method.XRD,SEM,TEM and conductivity of composite electrolyte GDC-NBO under different sintering temperature were studied.The research results of the composite electrolyte of GDC with molten salts Na2B4O7/Li2CO3(LCO)were discussed.It is obtained a composite electrolyte material with excellent performance at lower temperature.The research results of composite electrolytes GDC-NBO show that weight of GDC-NBO has not loss in the temperature range of 400? to 1200?.The new phase GdBO3 appeared on the surface of the composite electrolyte GDC-NBO sample after sintering at 800? for 3h.And the NBO phase exists in the composite electrolyte as an amorphous amorphous phase.It is a core—shell structure which GDC particles are surrounded by a uniform NBO thin layer in composite electrolyte GDC-NBO.The conductivity of composite electrolyte GDC-NBO at 800? is higher than that of the pure GDC by 36%.The research results of composite electrolyte GDC-NBO prepared with different sintering temperature(700?-1100?)show that the content of GdBO3 phase has increased on the surface of the composite electrolyte GDC-NBO sample,and the content of GDC phase decreases with the increase of sintering temperature.The ionic conductivity also increases with sintering temperature increasing.When the sintering temperature is 1000?,GDC-NBO forms the uniform core-shell structure and the largest conductivity is 0.022 Scm-1.The research results of the composite electrolyte of GDC with molten salts show that the temperature of melting point of the NBO with LCO is greatly reduced.It is about 600?.The phase of molten salts as an amorphous phase in the composite electrolyte GDC-NBO-LCO after sintered at 1000 ?.The conductivity of the composite electrolyte is enhanced with molten salts in low temperature.The conductivity of composite electrolyte GDC-NBO-LCO is 0.014Scm-1 at 600 C,which is higher than that of GDC-NBO by 519%.The composite electrolyte GDC-LCO-NBO has excellent performance at lower operating temperatures(600?).