Pathways for Li+ migration in Li1+xV3O8: Geometrical-topological analysis

In the present work, the crystal structure of the Li_1+xV₃O₈ (x = 0.1, 0.2, and 0.3) compounds was studied using both X-ray and neutron powder diffraction. This study provided a clear understanding of the lithium positions. We found that increase of the lithium content from 0.1 up to 0.3 in Li_1+xV₃O₈ gives rise to a statistical distribution of excessive lithium over a number of vacant interstitials between the [V₃O₈]⁻ layers. One dimensional migration map composed from the chain elementary channels along the [010] direction have been revealed by geometrical-topological analysis. These channels consist of vacant octahedral and tetrahedral positions which can accommodate Li⁺ ions diffusion via direct hopping mechanism. Bond valence site energy calculations confirmed one-dimensional diffusion with lithium migration barriers of 0.55 eV.