Direct characterization of the Li intercalation mechanism into α-V_2O_5 nanowires using in-situ transmission electron microscopy

摘要

The Li-V_2O_5 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-V_2O_5 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 a-V_2O_5 nanowire cathodes upon in-situ lithiation. Our results suggest that the pristine α-V_2O_5 nanowire forms a Li oxide shell which then acts as a solid state electrolyte to conduct Li~+ ions, and the bulk of the V_2O_5 nanowire undergoes transformation to the γ — Li_2V_2O_5 phase.