Metal (Li, Al, Ca and Ti) absorbed graphene with defects for hydrogen storage: first-principles calculations.

The characteristics of Li, Al, Ca and Ti metal adsorption on graphene with boron substitution and various vacancy defects are investigated using density functional theory calculation. Hydrogen adsorption characteristics and electronic structure of H2/metal adsorbed graphene were also calculated. It was found that Li, Al, Ca and Ti metal atoms are well dispersed on the graphene and can form a (2 x 2) pattern because clustering of metal atoms is hindered by the repulsive Coulomb interaction between the metal adatoms and the strong bonding force between the dispersed metal atom and graphene.

Theoretical investigation of Ti-adsorbed graphene for hydrogen storage using the ab-initio method.

Based on first-principles plane wave calculations, it was shown that boron substituted graphene with Ti metal atom adsorption can be used as a high capacity hydrogen storage material. Boron substitution in graphene enhances the Ti metal adsorption energy, which is much larger than that in the case of pure graphene, and than the Ti cohesive energy. The Ti metal atom can be well dispersed on boron-substituted graphene and can form a 2 x 2 pattern because the clustering of the Ti atoms is hindered by the repulsive Coulomb interaction between them.