论文标题
使用频率分辨的X射线吸收（FR-XAS），在固体氧化物燃料电池电极中揭示了依赖时间尺度的氧空位分布
Revealing timescale-dependent oxygen vacancy distributions in solid oxide fuel cell electrodes using frequency-resolved X-ray absorption (FR-XAS)
论文作者
论文摘要
开发电化学能量转化的材料需要深入了解在亚微米长度尺度上控制化学和物理速率的因素。许多工人试图开发针对这些长度尺度的原位或操作成像技术。但是，当前方法集中在稳态或逐步响应上。为了在空间和时间上探测电极过程，我们开发了X射线吸收成像（FR-XAS）的频率分辨实现，该实现可以测量全球正弦阻抗测量过程中Operando中局部电化学响应的实现。薄膜sofc阴极材料（$ la_ {1-x} SR_XCOO_ {3-δ} $）中氧空位分布的频率分辨的1-D图像显示，在实验上首次在实验上表明，与Warburg和Gerischer障碍相关的缺陷浓度。对这些图像的分析允许直接提取扩散和动力学速率参数，而与全局阻抗无关。
Development of materials for electrochemical energy conversion requires a deep understanding of the factors governing chemical and physical rates at submicron length scales. Many workers have sought to develop chemically sensitive in situ or operando imaging techniques targeting these length scales. However, current methods focus on steady-state or stepwise response. To probe electrode processes both spatially and temporally, we have developed a frequency-resolved implementation of X-ray absorption imaging (FR-XAS) that can measure local electrochemical response in operando during a global sinusoidal impedance measurement. Frequency-resolved 1-D images of the oxygen vacancy distribution in a thin film SOFC cathode material ($La_{1-x}Sr_xCoO_{3- δ}$) reveal, for the first time experimentally, the defect concentrations associated with a Warburg and Gerischer impedance. Analysis of these images allows direct extraction of diffusion and kinetic rate parameters, independent of the global impedance.
