Fig. 5: Free volume region that divalent Mg can occupy.
From: Amorphous oxide cathode enabling room-temperature rechargeable magnesium batteries
a Atomic structure of amorphous Mg0.33Ti0.11Mo0.22O obtained via molecular dynamics and ab initio calculations. Mo–O and Ti–O coordination polyhedra are shown in purple and light blue, respectively. Orange spheres represent Mg atoms. Green regions indicate free volume regions within the structure where bond valence sum (BVS) values are between 1.6 and 2.4, suggesting favorable sites for Mg occupancy. b Same structure as in a with coordination polyhedra removed to highlight the spatial distribution of Mg atoms and BVS-based free volume.
