Enhanced Charge Transport and Storage of Two-Dimensional Vanadium Pentoxide

Atomically thin two-dimensional (2D) materials have a number of key features for electrochemical charge storage including significant available surface area, quantum confinement in two dimensions, and distinct local structures (e.g. surface states, edge sites).   Vanadium pentoxide (V₂O₅) is a useful charge storage material based on its multiple available oxidation states which allows the material to store multiple ions and electrons within its structure during electrochemical cycling.  V₂O₅ has a high theoretical specific capacity of 294 mAh/g based on the two-electron charge storage process, and this capacity is significantly higher than the capacity of current commercial cathode materials (~160 mAh/g). However, typical forms of V₂O₅ exhibit severe capacity fading upon cycling. We have explored 2D forms of V₂O₅ to provide cathode materials with high capacities and improved cycling stability.  Two-dimensional V₂O₅ nanosheets were prepared from drying suspensions of ion-exchanged sodium metavanadate solutions. The synthesis, structural characterization, and electrochemical testing of 2D V₂O₅ will be presented to show the effect of various parameters (e.g. composition, particle size, aggregation, orientation) on the electrical and electrochemical properties.  The ability to control the structure and properties of 2D materials allows the development of improved charge transport and storage materials for batteries, supercapacitors, and other electrochemical applications.