The polarization response of a coplanar electrochemical capacitor covered with an ionic liquid as the electrolyte has been examined using a combination of two powerful analytic techniques, X-ray photoelectron spectroscopy (XPS) and scanning electron microcopy (SEM). Spatiotemporal distribution of the ionic liquid surface potential, upon DC or AC (square wave) biasing, has been monitored via chemical element binding energy shifts using XPS and secondary electron intensity variations using SEM. SEM’s high spatial resolution and speedy imaging together with application of a data mining algorithm made mapping of the surface potential distribution across the capacitor possible. Interestingly, despite the differences in the detection principles, both techniques yield similar polarization relaxation time constants. The results demonstrate the power of a synergistic combination of the two techniques with complementary capabilities and pave the way to a deeper understanding of liquid/solid interfaces and for performance evaluation and diagnostics of electrochemical devices.

中文翻译：

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共面电化学装置中离子液体极化的比较 Operando XPS 和 SEM 时空电位映射

使用两种强大的分析技术 X 射线光电子能谱 (XPS) 和扫描电子显微镜 (SEM) 的组合检查了覆盖有离子液体作为电解质的共面电化学电容器的极化响应。在直流或交流（方波）偏置下，离子液体表面电位的时空分布已通过以下方式进行监测使用 XPS 的化学元素结合能变化和使用 SEM 的二次电子强度变化。SEM 的高空间分辨率和快速成像以及数据挖掘算法的应用使得电容器表面电位分布的映射成为可能。有趣的是，尽管检测原理不同，但两种技术产生相似的极化弛豫时间常数。结果证明了具有互补能力的两种技术协同组合的力量，并为更深入地了解液体/固体界面以及电化学设备的性能评估和诊断铺平了道路。