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

Li-rich and catalytically active gamma-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 A(g), B-g, A(u), and B-u, 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 a 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.

Automated summary

By studying Li-rich and catalytically active gamma-LixV2O5 as a cathode, a direct correlation between Raman shift and Faraday current was observed, which can be used for analysis of Butler-Volmer kinetics. The potential of Raman-aided electrochemical detection method is being discussed.