Operando Raman Shift Replaces Current in Electrochemical Analysis of Li-ion Batteries: A Comparative Study

Abstract

Li-rich and catalytically active γ-LixV2O5 (x = 1.48) was investigated as a cathode for its heterogeneous charge transfer kinetics. Using a specially designed two-electrode system lithium half cell, Butler–Volmer analysis was performed, and Raman spectra were acquired in 18 mV intervals. A direct correlation was observed between the Raman shift of the active modes Ag,Bg, Au, and Bu, and the development of the Faraday current at the working electrode. The Raman intensity and the Raman shift were implemented to replace the current in a Tafel plot used for the analysis of Butler–Volmer kinetics. Striking similarities in the charge transfer proportionality constants α were found for current and Raman-based analysis. The potential of this new method of Raman-aided electrochemical detection at the diffraction limit is discussed.

Coupling Long‐Range Raman with X‐Ray Photoelectron Spectroscopy for Complementary Bulk and Surface Characterization of Battery Materials

“…The reference sample V 2 O 5 was used to validate the novel XP‐Raman spectroscopy setup. The obtained XPS and Raman results (see Table 2 and the Supporting Information) are fully consistent with data from our own separate measurements as well as that from the literature [22,38,39] . In particular, the characteristic Raman signature of V 2 O 5 is detected, including the stretching vibration of vanadyl (V=O) at 995 cm −1 [40] .…”

“…The obtained XPS and Raman results (see Table 2 and the Supporting Information) are fully consistent with data from our own separate measurements as well as that from the literature. [22,38,39] In particular, the characteristic Raman signature of V 2 O 5 is detected, including the stretching vibration of vanadyl (V=O) at 995 cm À 1 . [40] In contrast, highly lithiated γ-Li x V 2 O 5 shows a red-shifted V=O stretch (A 1g mode) at 953 cm À 1 , [22] highlighting the sensitivity of this mode to structural changes.…”

Monitoring electrode/electrolyte interfaces of Li‐ion batteries under working conditions: A surface‐enhanced Raman spectroscopic study on LiCoO2 composite cathodes

“…In situ Raman experiments were performed in a 180° backscattering geometry using a commercial test cell (EL Cell) 33 equipped with a glass optical window (see Figure 1). The battery cell consists of two electrodes separated by a layer of glass fiber filter paper soaked with electrolyte to prevent a short circuit.…”

Operando spectroelectrochemistry of bulk-exfoliated 2D SnS2 for anodes within alkali metal ion batteries reveals unusual tin (III) states

“…Prior inclusion of the exfoliated few-layer SnS 2 into the battery, in order to improve the conductivity, the relatively broad-bandgap 2D SnS 2 material (2.3 eV) was mixed with graphite, but with exclusion of a binder in order to avoid overlapping of Raman spectra with the signals of poly (vinylidene difluoride) (Radtke and Hess, 2021) (Gajendiran and Rajendran, 2011). In previous studies, after mixing of 2H SnS 2 with L-cysteine and after subjecting the mixture to hydrothermal reaction, a series of additional Raman features in form of pentatomic and heptatomic rings were observed (Shown et al, 2018).…”