(430d) Visualising Reactivity at Electrified Interfaces with the Surface Forces Apparatus: From Corrosion to SEI Formation on Li-Anodes

Electrochemical solid|liquid interfaces are critically important for materials for energy storage, harvesting, and conversion, and for material stability in general. Yet, a real-time visualization of dynamic processes at electrified solid|liquid interfaces with close to atomic resolution is extremely challenging. Processes such as an electrochemical surface modification, or localized surface reactions in confinement are inherently difficult to visualize in real time with micro-to-nano scale resolution.

In this presentation I will highlight recent advances in characterizing electrochemical interfaces with the electrochemical surface forces apparatus (EC-SFA), ranging from the real-time measurement of corrosion rates in confined localized areas to the electrochemical growth of solid electrolyte interfaces on Li-battery anodes.

First, I will show that the real-time capability of the electrochemical SFA allows us to visualize oxide reduction/oxidation processes of noble metal catalysts in real-time with sub-nanometer resolution, and it provides detailed insight into the structure of the electric double layer under varying charging conditions, including the charging dynamics in confined areas.

I will further demonstrate how multiple-beam-interferometry (MBI) in reflection mode can be utilized as a real-time monitoring tool for corrosion of nanometer confined bulk metallic surfaces and metallic thin films. I will demonstrate capabilities of reflection mode MBI, comparing the initial crevice corrosion mechanism on confined nickel and a Ni₇₅Cr₁₆Fe₉ alloy in real time.

Finally, I will demonstrate that employing an electrochemical surface forces apparatus also provides unique insight into the growth and the emerging mechanical properties of interfacial decomposition products forming the so-called solid-electrolyte interphase (SEI) of a Li ion battery.