Alkali Ion Incorporation into V2O5: a Noncovalent Interactions Analysis

Understanding the interaction of alkali metals with layered materials like vanadia is important for a range of technological applications such as energy storage and heterogeneous catalysis. Here we used the NCI (noncovalent interactions) index to analyze the nature of the chemical bonding between inserted alkali atoms (Li, Na, and K) and vanadia. We found that alkali atoms ionize in bulk vanadia making directional ionic bonds with neighboring oxygen atoms, whereas the dispersive interactions between vanadia layers remain unmodified by the presence of alkali ions. Interestingly, we show how the NCI analysis discriminates among the different vanadium oxygen types of bond, capturing even finer interactions involving reduced vanadium sites or ring stabilization. In addition, we explored dynamic effects, concluding that the directionality of all interactions is preserved at 500 K.