Interfaces in Electrochemical Energy Storage*

Electrochemical energy storage systems are inherently complex making detailed characterization of their operation challenging. We have taken a reductionist approach by using simple, but relevant, model systems than are amenable to detailed investigations. This talk will describe in situ X-ray scattering and spectroscopy experiments taking this approach and aimed at understanding the lithiation of Si single crystal anodes [1], the molecular ordering of organic solvent molecules at solid-electrolyte interfaces [2] and the plating and stripping of Li metal anodes. We used X-ray reflectivity to investigate, in real time, the electrochemical lithiation of single crystalline Si(100) electrodes, which allows us to gain nanoscale, mechanistic insight into the lithiation of Si and the formation of the solid electrolyte interphase (SEI) surface film on the Si anode. This approach was also used to determine the structure non-aqueous electrolytes at the solid-liquid sapphire (001) interface. We fianlly describe In situ X-ray diffraction and ex situ X-ray spectroscopy used to understand the nucleation and growth of Li on Cu current collectors.

[1] Cao et al., Nanolett , NanoLetts 16,7394 (2016).; Adv Mater Inter 4, 1700771 (2017).
[2] Steinruck et al., Ener Envron Sci., submitted.