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

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2020-06, Vol.8 (23), p.118-1181
• Main Authors: Walker, Mitchell J, Jarry, Angelique, Pronin, Nick, Ballard, Jake, Rubloff, Gary W, Brillson, Leonard J
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d0ta03204b

Vanadium pentoxide (V 2 O 5 ) 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 V 2 O 5 from the free surface to the thin film bulk several hundred nm below as a function of lithiation. DRCLS measurements of V 2 O 5 interband transitions are in excellent agreement with density functional theory (DFT) calculations. The direct measure of V 2 O 5 '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 V 2 O 5 irreversibly, as well as methods to mitigate them in solid-state batteries. V 2 O 5 electronic band structure from cathodoluminescence reveals how lithiation creates octahedral distortion and not oxygen vacancies or conversion reactions.