Design of superhalogens using a core–shell structure model

Superhalogens, which have larger electron affinity than any halogen, play an important role in physical chemistry and materials design because of their applications in hydrogen storage and lithium-ion batteries. Inspired by the unique geometries and electronic properties of II-VI/III-V cage clusters, particularly the experimentally synthesized B₁₂N₁₂, we propose a core-shell structure model to design new superhalogens. The idea is assessed by conducting ab initio calculations on endohedral cage clusters X@B₁₂N₁₂ (X = F, Cl, Br) and other similar systems. With an exceptionally large electron affinity of 5.36 eV, the stable F@B₁₂N₁₂ cluster behaves as a novel superhalogen that can serve as a building block for Li salts and hyperhalogens. The findings highlight a new route for the discovery of superhalogens and provide useful building blocks for the bottom-up design of materials.