Regensburg 2022 – scientific programme
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O: Fachverband Oberflächenphysik
O 28: Organic Molecules at Surfaces 3: Theory
O 28.5: Talk
Tuesday, September 6, 2022, 11:30–11:45, S051
The sensitivity of NMR chemical shifts to organic/inorganic interfaces — •Viviana Piccinni1, Emmanouil Veroutis2, Karsten Reuter1, Josef Granwehr2, and Christoph Scheurer1 — 1Fritz Haber Institute of the Max Planck Society, Berlin — 2Forschungzentrum Jülich, IEK-9, Jülich
Composite polymer/ceramic solid electrolytes are promising materials for Li-ion batteries due to their high stability and safety. Yet, their organic/inorganic interface is believed to hinder the ionic conduction. NMR experiments on a poly(ethylene oxide)/Li1.5Al0.5Ti1.5(PO4)3 electrolyte have shown that Li ions cross the interface on a timescale of seconds. To remedy the problem, mechanistic insights are required, but even the polymer/ceramic interface structure is unknown.
We therefore investigate representative potential binding situations between the two materials by computing the NMR shielding tensors, in order to verify whether there is a significant change in the chemical shifts depending on the interface structure. Due to the high computational cost, a simplified model exhibiting the same local chemical interactions is constructed, composed by an AlPO4 slab and ethane-1,2-diol. NMR measurements on an AlPO4/methanol system have also been carried out.
While the computed NMR properties are sensitive to changes in the interface structure, experiments reveal no chemical shifts variations in the 1H NMR methanol/AlPO4 spectra relative to neat methanol. This can be ascribed to the presence of surface water in AlPO4, which would leave no available binding sites for methanol/AlPO4 interactions.