Naslov
Electronic Structure of Sulfur Atoms in Li-S Systems Studied by Laboratory-Based X-ray Emission Spectroscopy

Autori
Petric, Marko ; Rajh, Ava ; Vizintin, Alen ; Drvarič Talian, Sara ; Dominko, Robert ; Kavčič, Matjaž

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

Izvornik
1st Virtual Conference on X-ray Spectrometry / Michael, Kolbe ; Diane, Eichert - , 2021, 24-24

Skup
1st virtual conferenceon X-ray Spectrometry

Mjesto i datum
Online, 21.06.2021. - 24.06.2021

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Li-S battery, laboratory-based XES, DFT calculations

Sažetak
The 2019 Nobel Prize in Chemistry was awarded to John Goodenough, M. Stanley Whittingham and Akira Yoshino for the development of lithium-ion batteries. They initiated rechargeable world, but the need for high gravimetric energy density required for the goals of transportation still makes the batteries very interesting research area. Lithium-sulfur (Li-S) batteries are one of the most promising candidates for next generation of batteries in applications where high energy density is required. In general, the electrochemical 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, which are soluble in the electrolyte and affect the overall battery performance. In order to understand complex electrochemical reactions during battery charge/discharge process, numerous analytical techniques have been used [1]. In the present work, the laboratory-based x-ray emission spectroscopy (XES) is used to perform chemical speciation of the sulfur atom in Li-S standards, pre-cycled battery cathodes, and also in the Li-S battery during cycling (operando conditions). The high-resolution Kα (Core-to-Core) and Kβ (Valence-to-Core) xray emission spectra of sulfur were recorded by in-vacuum crystal spectrometer [2] combined with the particle induced x-ray emission (PIXE). Energy shifts of the Kα line were correlated with the calculated effective charge of sulfur atoms and used to track the reduction of the elemental sulfur to lithium sulfide [3]. The measured Kβ spectra of lithium polysulfides Li2Sx (x = 2, …, 8), which appear in the Li-S systems, were interpreted using ab-initio quantum chemical calculations based on density functional theory (DFT), employing the StoBe-deMon and cp2k software packages [4]. The results presented here have the potential to bring the characterization of the sulfur based systems from synchrotrons down to smaller laboratories.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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