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 applied low or high 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.