In Situ Raman Observation of Zinc-Induced Structural Dynamics and Charge Transfer of a Layered V₂O₅

Abstract

In situ techniques to disclose electrochemical and interfacial behavior between electrode and electrolyte in a quantitative manner are in high demand in numerous fields including electrochromism, energy storage as well as basic science research. This work demonstrates a self-made in situ Raman spectra technique coordinating with an electrochemical workstation and its utility for zinc-induced structural dynamics and charge transfer of a layered V2O5. The increase or decrease of Raman activity modes of V-O3, O1-V-O2, and O1-V-O3 at low or high applied voltages is probably due to the presence of ‘free pathway’ within layers. An interpretation is proposed where the two stages of bidirectional reversibility of Zn2+ intercalation and deintercalation from ‘free pathway’ and V2O5 matrix occur via an electrochemical process, followed by Zn2+ continuous aggregation, fusion and possible transformation to ZnxV2O5. A distinct difference between Li+-based and Zn2+-based electrolytes is that the Raman active modes between V atom and apical oxygen are almost not enhanced or weakened for V2O5 in Zn2+-based electrolyte, most likely due to the greater Coulomb force of Zn2+ on V2O5 matrix than that of Li+. These observations have implications for understanding the performance and stability of electrochromic devices.