Fabrication and optimization of La_0.4Sr_0.6Co_0.2Fe_0.7Nb_0.1O_3-δ electrode for symmetric solid oxide fuel cell with zirconia based electrolyte

Na Xu¹，Tenglong Zhu¹，Zhibin Yang¹，Minfang Han^1,2

1. Union Research Center of Fuel Cell, School of Chemical and Environmental Engineering, China University of Mining and Technology2. State Key Laboratory of Power Systems, Department of Thermal Engineering, Tsinghua University

摘 要：La_0.4Sr_0.6Co_0.2Fe_0.7Nb_0.1O_3-δ（LSCFN）was applied as both anode and cathode for symmetrical solid oxide fuel cells（SSOFCs）with zirconia based electrolyte.The cell with LSCFN electrode was fabricated by tape-casting and screen printing.Fabrication process was optimized firstly by comparing co-sintering and separate-sintering of electrode and electrolyte.To further improve the LSCFN electrode properties,oxygen ionic conductor of Gd_0.1Ce_0.9O_2-δ（GDC）was added into the LSCFN electrode.The preferred composition of LSCFN-GDC composite electrode was found to be 1:1 in weight ratio with polarization resistance of 0.16Ωcm²at 800^℃.The maximum power densities of LSCFN-GDC||GDC/YSZ/GDC||LSCFN-GDC tested in H₂and CH₄with 3%H₂O were 395 m W cm^-2and 124 m W cm^-2at 850^?C,respectively,which were much higher than that of LSCFN||GDC/YSZ/GDC||LSCFN cells at same condition,possibly due to the extension of the triple phase boundary induced by the addition of GDC.The cell showed reasonable stability using H₂and CH₄with 3%H₂O as fuels and no significant power output degradation was observed after total 200 h operation.

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