对流-扩散法制备多孔衬底支撑梯度结构电解质薄膜

以多孔氧化铝(porous alumina,p-Al2O3)为模型多孔电极衬底材料,利用对流-扩散效应成功制备得到了具有梯度结构的8%(以摩尔计)钇稳定氧化锆(yttria-stabilized zirconia,YSZ)电解质薄膜.该方法新颖、经济简单、适合于制备大尺寸平板型固体氧化物燃料电池中多孔电极支撑的电解质薄膜.利用扫描电镜和X射线角散分析技术对所制备电解质薄膜/p-Al2O3样品进行了微结构测试和表征.结果表明:由该方法在多孔衬底上实现的YSZ电解质薄膜由生长于衬底表面上的均匀致密层(≈10μm)和衬底表面下孔道中均匀填充层(≈50μm)与弥散填充层(≈250μm)构成,且各层厚度可通过改变对流-扩散沉积条件得到调节.

FABRICATION OF POROUS SUBSTRATE-SUPPORTED ELECTROLYTE THIN FILMS WITH GRADIENT MICROSTRUCTURE VIA CONVECTION-DIFFUSION METHOD

8% (in mole) yttria-stabilized zirconia (8-YSZ) electrolyte thin films with gradient microstructures were successfully fabricated on porous alumina (p-Al2O3) substrates as a model porous electrode for solid oxide fuel cells (SOFCs) via a constituent species convection-diffusion route. This novel technique is simple, economical and potentially suitable for the fabrication of electrode-supported electrolytes for planar SOFCs with large dimensions. With the help of scanning electron microscopy and X-ray angular dispersion analysis, it is found that the 8-YSZ films supported by p-Al2O3 are structurally composed of a dense surface layer (～10 μm in thickness) on top of the substrate, a uniform in-filling layer (～50 μm) just under the surface of the substrate and an immediate diffuse layer reaching as deep as ～250μm. The particular thickness of each part in this gradient profile may be changed with the convection-diffusion conditions.