Performance degradation of solid oxide fuel cells analyzed by evolution of electrode processes under polarization

Solid oxide cell electrolytes deposited by atmospheric suspension plasma spraying at high velocity and high temperature

“…While some degradation of the fuel electrode process at 2000–4000 Hz occurred, degradation of cell performance was predominantly attributed to the air electrode process at 20–40 Hz for both cells. Numerous studies have observed degradation in the 20–100 Hz frequency change [49, 50, 57, 58], but to a much lesser extent than the observations here. Endler et al.…”

Study of solid oxide electrolysis cells operated in potentiostatic mode: Effect of operating temperature on durability

“…The long-term durability of SOECs and stacks has been extensively investigated in the past couple of decades. Most of the previously conducted long-term tests were carried out in galvanostatic mode [13][14][15][16][17][18] , i.e. current is kept constant while voltage is changing due to degradation or activation.…”

Evolution of Electrochemical Characteristics of Solid Oxide Fuel Cells During Initial-Stage Operation

“…目前已经建立的 EIS 解析方法包括等效电路拟合法 (ECM)、 阻抗差异分析法(ADIS)、 弛豫时间分布法(DRT) 等. 在本课题组之前的工作中, 已经通过 DRT/ECM 方 法实现了对纽扣电池 [8] 、工业大尺寸电池 [9] 中各项电极 过程的分辨, 并在此基础上基于带载 EIS 解析初步研究 了电池性能演变机制 [10] . 广泛的实验测试结果表明, SOFC 在运行初期(约前 100 h)的性能演变最为显著和复 杂: 部分电池的性能在这一阶段迅速降低 [10][11] , 也有部 分电池的性能在这一阶段先有所上升、之后逐渐降 低 [12][13] .…”

“…SOFC 在运行初期依次经历还原、活化和老化阶段, 需要注意的是, 每一阶段的持续时间、性能变化幅度可 能会受到电池制备工艺的影响. 例如, 对于阳极本身孔 隙率较大的电池(如造孔剂含量较高、烧结温度较低等), 由于阳极还原更为容易, NiO 很快就被彻底还原, Ni 的 初期烧结团聚也很快发生, 因此随后的活化阶段可能历 时很短, 甚至会 "跳过" 活化阶段直接进入老化阶段, 如 图 7 中"Fast activation"途径所示, 这种现象在之前的 研究中也已被观察到 [10][11] .…”

“…此外, 在我们之前的研究中已经证实, SOFC 在更 长时间的运行中(数百小时)性能衰减的主导因素与上述 老化阶段相同, 仍然是阳极界面反应阻抗的持续增 加 [10] . 但是电池的性能衰减速率会随着运行时间的增 加而逐渐减小, 主要是由于运行数百小时后阳极 Ni 颗 粒的形貌逐渐达到稳态, 烧结团聚速率逐渐降低.…”