基于应力分析Ni-Fe合金支撑固体氧化物燃料电池的结构稳定性研究

Structural Stability of Ni-Fe Supported Solid Oxide Fuel Cells Based on Stress Analysis

本文以NiO和Fe2O3为原料,应用流延、丝网印刷、高温共烧结和原位还原的工艺制备多孔金属支撑固体氧化物燃料电池(MS-SOFC)。系统研究了支撑体中Fe含量对MS-SOFC的残余应力、抗弯断裂强度和电化学稳定性的影响。结果表明,在NiO中加入10at%Fe2O3,使得支撑体致密化开始温度提高到937℃,残余应力和变形翘曲度分别低至70MPa和0.15mm;电池还原之后,Ni0.9Fe0.1支撑SOFC骨架表面孔隙率为40.22%,抗弯断裂强度达到最大值62.34MPa;电化学测试过程中,Ni0.9Fe0.1支撑SOFC在650℃下,以H2为燃料,在400mA·cm^–2电流密度下可以稳定运行60h,主要因为电池具有较高的抗弯断裂强度,能够抵抗运行过程中的热应力。该研究工作为MS-SOFC结构设计和性能稳定性优化提供重要的理论依据。

Metal supported solid oxide fuel cells (MS-SOFCs) were fabricated with NiO and Fe2O3 by tape casting, screen printing, sintering and in-situ reducing process with NiO and Fe2O3. The fraction effects of Fe on residual stress, bending strength and electrochemical stability of MS-SOFC were systematically investigated. The addition of 10at% Fe2O3 in characteristic support elevated densification starting temperature up to 937 ℃, and reduced residual stress and buckling deformation to 70 MPa and 0.15 mm, respectively. After reduction, Ni0.9Fe0.1supported SOFC presented the maximum bending strength of 62.34 MPa due to the lowest porosity of 40.22% in metal scaffold. MS-SOFC steadily operated for 60 h in durability test with H2 as the fuel at a constant current density of 400 mA·cm^–2 and 650 ℃. This superior performance was attributed to the higher fracture strength of Ni0.9Fe0.1 alloy support SOFC, which effectively resisted the thermal stress in operation. This research provides a promising theoretical basis for structure design and optimization of MS-SOFC.