过渡层对掺有Al2O3的YSZ电解质支撑SOFC的性能影响

采用甘氨酸－硝酸盐燃烧法合成阳极材料NiO以及阴极材料La0.8Sr0.2MnO3（LSM）.将电解质8mol%钇稳定氧化锆（YSZ）和掺有4wt% Al2O3的YSZ压片后在1450℃烧结4h.在掺有氧化铝电解质的阳极侧涂刷过渡层后于1200℃烧结1h.以加湿氢气（含3％体积比H2O）为燃料,环境空气为氧化剂,测试了三种电池的输出性能和交流阻抗谱.结果表明:850℃时,含Al2O3的电解质输出性能最差,输出功率约为83mW/cm2.含Al2O3并具有过渡层的电池输出性能最好,输出功率约为120mW/cm2.通过交流阻抗谱分析,后者电池的欧姆电阻与界面电阻均比前者明显减小.表明YSZ中添加的Al2O3在高温烧结过程中,与阳极材料NiO发生反应生成不导电的镍铝尖晶石.过渡层的使用,不仅保留了Al2O3对电解质的贡献,也抑制了不导电的镍铝尖晶石的生成.

The Influence of Buffer Layer upon the Performance of SOFC Supported by YSZ Electrolyte with Al2O3

NiO and La0.8Sr0.2MnO3 were synthesized by processing glycine-nitrate combustion. The 8mol% yttrium stabilized zirconia (YSZ) and the YSZ with 4wt% Al2O3 dopant electrolyte were pressed into wafer and sintered at 1450℃ for 4h. The anode side of the latter was coated with the buffer layer, which was sintered at 1200℃ for 1h. The output performance and AC impedance spectroscopy of the three kinds of fuel cells with humiliated hydrogen (3vol%H2O) as fuel and the ambient air as oxidant were tested. The results indicated that the electrolyte with Al2O3 performed the worst at 850℃ with the output power density being 83mW/cm2; the cell doped with Al2O3 as well as coated the buffer layer performed the best at the same temperature with the output power density being 120mW/cm2. AC impedance spectroscopy analysis indicated that the interface resistance and ohmic resistance of the latter were markedly less than that of the former. This indicated that insulative nickel aluminum spinel was generated by Al2O3 and NiO being sintered at a high temperature. Therefore, the application of the buffer layer not only kept the contribution of Al2O3 to the electrolyte but also reduced the generation of the insulative nickel aluminum spinel.