Nanoscale depth and lithiation dependence of V2O5 band structure by cathodoluminescence spectroscopy

Abstract

Vanadium pentoxide (V₂O₅) is a very well-known cathode material that has attracted considerable interest for its potential use in solid-state lithium-ion batteries. We pioneer the use of depth-resolved cathodoluminescence spectroscopy (DRCLS) to monitor the changes in the electronic structure of lithiated V₂O₅ from the free surface to the thin film bulk several hundred nm below as a function of lithiation. DRCLS measurements of V₂O₅ interband transitions are in excellent agreement with density functional theory (DFT) calculations. The direct measure of V₂O₅'s electronic band structure as a function of lithiation level provided by DRCLS can help inform solid-state battery designs to further withstand degradation and increase efficiency. In particular, these unique electrode measurements may reveal physical mechanisms of lithiation that change V₂O₅ irreversibly, as well as methods to mitigate them in solid-state batteries.