Vacancy Associates Evoked Hematite Mesocubes with Enhanced Efficiency in Li Storage Behaviors

Vacancies can significantly determine the physical and chemical properties of inorganic materials, which play crucial roles in many areas of applications, such as electronics, catalysis, and energy storage devices. However, little is known about the relationships between vacancy feature and lithium (Li) storage behaviors of inorganic materials. Here, we discovered that the types and abundance of atom vacancies on anode materials strongly affect their Li storage performance. By comparing the Li storage performance between two hematite (α-Fe₂O₃) cubes with similar morphology but different predominant vacancies and applying the density functional theory computations on the Li-ion diffusion rate and substitution energy of Fe ions by Li ions, we show that the vacancies, in particular the large size vacancies on the surface of anode materials, could effectively reduce the barriers of Li-ion diffusion and decrease the substitution energy of Fe ions. This new finding may advance the design and development of novel anode materials with excellent performance for Li-ion batteries.