Naslov
Chemical speciation of sulfur in lithium polysulfides via Core-to-Core and Valence-to-Core XES

Autori
Kavčič, Matjaž ; Petric, Marko ; Vizintin, Alen

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of abstracts / European Conference on X-Ray Spectrometry / Kavčič, Matjaž ; Žitnik, Matjaž ; Hrast, Mateja ; Bučar, Klemen - Ljubljana : Narodna in univerzitetna knjižnica u Ljubljani, 2018, 175-175

ISBN
978-961-264-126-9

Skup
European Conference on X-Ray Spectrometry — EXRS-2018

Mjesto i datum
Ljubljana, Slovenija, 24.06.2018. - 29.06.2018

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
DFT calculation, Valence to Core XES, LiS battery

Sažetak
The x-ray inner shell spectroscopic methods are commonly used for study chemical environment of the central atom. The x-ray absorption spectroscopy (XAS), commonly used at the synchrotron probes the unoccupied states above the Fermi level. In contrast to XAS, in the x-ray emission spectroscopy (XES) the occupied state are studied by recording x-ray emission following inner shell ionization. The XES technique can be performed also with laboratory excitation sources, e.g. x-ray tube or proton beam. The necessary condition for performing XES is the high-energy resolution in the detection channel. The XES technique can be applied to characterize the electronic structure of the elements in different system in different field of science. One interesting system are Li-S batteries, which are considered as one of the most promising candidates for future batteries in high energy density applications [1]. In general, the reaction in the Li-S batteries is known, the elemental sulfur (α-S8) is reduced to lithium sulfide (Li2S). In reality, the process goes through a series of stepwise redox reaction forming various long-chain lithium polysulfides. In this work, the high energy resolution x-ray emission spectroscopy is used to examine the local electronic structure of the sulfur atom in the three phases which appear in the Li-S battery ; elemental sulfur (α-S8), lithium polysulfides Li2Sx (x = 2, . . . , 8) and lithium sulfide (Li2S). The high-resolution Kα and Kβ emission spectra of the sulfur were recorded by in-vaccum crystal spectrometer[2] combined with the particle induced x-ray emission (PIXE) in our laboratory, at the Jozef Stefan Institute. In order to interpret measured spectra, the quantum chemical calculations based on the density functional theory (DFT) were performed. The energy shifts of the Kα line which originate from the Core-to-Core (CtC) electron transition were correlated with calculated effective charge of sulfur atom. The measured Kβ spectra, which correspond to the Valence-to-Core (VtC) transition were compared to the ab-initio calculations based on density functional theory (DFT).

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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