Direct characterization of the Li intercalation mechanism into α-V2O5 nanowires using in-situ transmission electron microscopy

Abstract

The Li-V2O5 system has been well studied electrochemically, but there is a lack of systematic in-situ studies involving direct investigations of the structural changes that accompany the lithiation process. The open-cell battery setup inside a transmission electron microscope is ideal for studying the reaction pathway of intercalation of Li+ into nanowire cathodes. In this work, we utilize in-situ transmission electron microscopy to study the Li-V2O5 system. More specifically, we employ electron beam diffraction and electron energy-loss spectroscopy (EELS) in an open-cell battery setup to examine the phase changes within α-V2O5 nanowire cathodes upon in-situ lithiation. Our results suggest that the pristine α-V2O5 nanowire forms a Li oxide shell which then acts as a solid state electrolyte to conduct Li+ ions, and the bulk of the V2O5 nanowire undergoes transformation to the γ−Li2V2O5 phase.