A novel approach for substantially improving the sinterability of BaZr04Ce0.4Y0.2O3-δ electrolyte for fuel cells by impregnating the green membrane with zinc nitrate as a sintering aid

BaZr0.4Ce0.4Y0.2O3-delta, (BZCY4) has been widely considered to be a promising electrolyte material for H+-SOFC, but it is restricted to commercial applications due to its poor densification behavior. A dense BZCY4 pellet was obtained by sintering at 1250 degrees C after impregnating the material with a zinc nitrate solution. The dilatometer curves and scanning electron microscopy (SEM) images indicated that the sinterability of the BZCY4 material is effectively improved by impregnating the green membrane with 4 wt% Zn. Moreover, EDX mapping indicated that the Ba, Zr and Ce elements were homogeneously distributed in the BZCY4 + 4 wt% Zn sample sintered at 1250 degrees C. In addition, an integrated SOFC employing a BZCY4 + 4 wt% Zn electrolyte was successfully fabricated without any cracks and delamination by impregnating the BZCY4 electrolyte membrane with zinc nitrate as a sintering aid. This single cell with a 25 mm thick BZCY4 + 4 wt% Zn electrolyte membrane exhibited power densities as high as 360 and 276 mW cm(-2) at 700 and 600 degrees C, respectively. Electrical conductivity measurements demonstrated that the total conductivities of BZCY4 + 4 wt% Zn were 0.46 x 10(-2) S cm(-1), 0.56 x 10(-2) S cm(-1), 0.20 x 10(-2) S cm(-1) and 0.40 x 10(-2) S cm(-1) at 600 degrees C in air, wet air, 10% H-2-Ar and wet 10% H-2-Ar, respectively. (c) 2013 Elsevier B.V. All rights reserved.