Revealing solid electrolyte interphase formation through interface-sensitive Operando X-ray absorption spectroscopy.

The solid electrolyte interphase (SEI) that forms on Li-ion battery anodes is critical to their long-term performance, however observing SEI formation processes at the buried electrode-electrolyte interface is a significant challenge. Here we show that operando soft X-ray absorption spectroscopy in total electron yield mode can resolve the chemical evolution of the SEI during electrochemical formation in a Li-ion cell, with nm-scale interface sensitivity. O, F, and Si K-edge spectra, acquired as a function of potential, reveal when key reactions occur on high-capacity amorphous Si anodes cycled with and without fluoroethylene carbonate (FEC).

Hybrid Organic-Inorganic Rotaxanes, Including a Hetero-Hybrid [3]Rotaxane Featuring Two Distinct Heterometallic Rings and a Molecular Shuttle.

[2] and [3] hybrid rotaxanes are reported based on {Ti M} rings (M is a trivalent metal such as Fe or Ga ). NMR studies show that [2]rotaxanes can act as molecular shuttles, while EPR studies of [3]rotaxanes show weak interactions between the paramagnetic components of the supramolecular assemblies.