Figure 7.

Single-crystalline V₂O₅·xH₂O nanorings and microloops, and yolk-shell V₂O₅ microspheres. (a-h) SEM images of single-crystalline V₂O₅·xH₂O nanorings and microloops [43]. (i-l) SEM images of yolk-shell V₂O₅ microspheres. The insets of (j) and (k) show the schematic structure of yolk-shell V₂O₅ microspheres. Adapted from [44] and reproduced with the permission of the Royal Society of Chemistry.