Investigation of the reaction mechanism of lithium sulfur batteries in different electrolyte systems by in situ Raman spectroscopy and in situ X-ray diffraction

Abstract

In liithium–sulfur battery the lithium metal surface was analyzed by in situ Raman spectroscopy.

Application of Operando X-ray Diffraction and Raman Spectroscopies in Elucidating the Behavior of Cathode in Lithium-Ion Batteries

“…The cell components can be arranged in different configurations, depending on the components to be examined. Various cell components are amenable to analysis, for example, the changes in the electrodes, the species in the electrolyte on both sides of the separator or changes to the separator surface (Zhu et al, 2017). Figures 1b1,b2 show the schematic diagrams of the in-situ Raman cells for analyzing the electrode surface (Figure 1b1) and electrolyte on the lithium metal side or separator surface (Figure 1b2); (Figure 1b3) after filtering the elastic scattered radiation out, the inelastic Raman scattering signal is collected (Figure 1b3) and expressed in (Figure 1b4) from where the local structure, such as chemical bonds and symmetry, oxidation state of the ions can be obtained (Figure 1b5).…”

“…PS1 and PS2 are attributed to the PSs-SiO 2 interactions (vertical black dashed lines). Li 2 S is symbolized by a dashed-dotted black vertical line; * is from cell package (Conder et al, 2017); with permission from Springer Nature; (b) XRD patterns of a cell during 1st cycle with corresponding (Continued) FIGURE 5 | electrochemical plot; arrow, Li 2 S; *, cell package; bold lines indicate initial appearance of solid phase and subsequent disappearance (Walus et al, 2013); with permission from RSC; (c) Raman spectra from 1 M LiTFSI-DOL-DME electrolyte on the lithium side during first cycle; * separator (Zhu et al, 2017). (dA-C) Raman spectra of sulfur cathode during discharge; (dD) Cyclic voltammetry of as-prepared sulfur-carbon cathode and potential dependence of the peak intensities (Wu et al, 2015); with permission from ACS.…”

“…On the other hand, Raman spectroscopy can clearly detect different species formed in the cathode and dissolved in the electrolyte (Yeon et al, 2012;Hannauer et al, 2015;Paolella et al, 2018). Figure 5c (Zhu et al, 2017) displays the development of Raman spectra of the electrolyte (1M LiTFSI-DME-DOL) near the lithium anode during the 2nd cycle. It is interesting to note that elemental sulfur is observed at the end of charge near lithium anode; this sulfur is β-S 8 according to operando XRD, which cannot be distinguished from α-S 8 by Raman spectra in the measured region.…”

Quantitative Galvanostatic Intermittent Titration Technique for the Analysis of a Model System with Applications in Lithium−Sulfur Batteries

“…Impedance spectroscopy has also been used to evaluate the individual contributions from electrolyte resistance, charge transfer, ion diffusion and electrode surface layers, which in turn has been used to refine mechanistic models of Li−S cells,, as well as to investigate capacity fading . Other experimental techniques used to elucidate redox and diffusion properties in Li−S cells include XAS, in‐operando optical imaging of the temporal and spatial distribution of polysulfides, UV‐Vis spectroscopy, NMR, EPR/ESR,, XRD, Raman, HPLC, and gas evolution, among other electrochemical studies . The mechanism and kinetics of Li 2 S precipitation has been studied using chronoamperometry .…”

In Situ Techniques for Developing Robust Li–S Batteries

“…It has been widely applied to determine the phase composition and crystallinity of crystalline materials in the battery‐research field . In situ laboratory XRD characterization of LSBs has focused on understanding the intermediate LPS phases that form during battery discharging and charging, for example, Li 2 S and Li 2 S 2 formation, sulfur reduction (during discharging), oxidation (during charging), and S recrystallization …”