DFT study of efficient hydrogen storage on B12@Ca14 cage

Abstract

Hydrogen, as a zero-carbon energy carrier, has attracted considerable attention of scientific community. Therefore, the development of hydrogen storage materials has always been a hot topic. Currently, there have been numerous researches on hydrogen storage performance of boron nanostructures decorated by alkaline-Earth atoms. Here based on first-principles calculations, a core–shell B12@Ca14 structure with D 2h symmetry has been proposed. Surprisingly, 14 Ca atoms in the metal shell of the B12@Ca14 structure can form a good package for B12 core without aggregation, thus forming a novel hydrogen storage material with all-metal atomic shell, which also provides a new idea for the research of hydrogen storage materials. Molecular dynamics simulation and vibration frequency analysis have been revealed the thermodynamic and kinetic stability of the B12@Ca14 structure. The analysis of binary system illustrates that the structure can be used as a building block for nano-assembly. For the hydrogen storage performance of the structure, the research results show that the B12@Ca14 structure can adsorb about 75 H2 molecules, with a high hydrogen storage mass density of 18.0 wt%. What’s more, non-covalent interaction analysis verifies that H2 molecules are adsorbed by weak interactions.