DFT study for hydrogen storage on γ-Boron-Graphyne decorated with Li atoms

• Boron substitution on a pristine γ-Graphyne results in forming a 2D structure. • Gravimetric capacity for H 2 storage on 18Li—γ-B-Graphyne structure is 6.94 wt%. • Adsorption energies are in the range of 0.321–0.353 eV. • Adsorption energies suggest that H 2 adsorption at ambient temperatures is possible. • Equilibrium pressure is in the range of 18–22 MPa for the 18Li—γ-B-Graphyne. This work reports theoretical calculations for hydrogen storage on γ-B-Graphyne structure using DFT. The pristine γ-Graphyne is a 2D structure, with 2 kinds of hexagonal rings. The boron substitution on a pristine γ-Graphyne is characterized by the formation of a 2D structure, the molecular structure of the boron substitution on a pristine γ-Graphyne is very close to γ-Graphyne structure. Boron substitution on γ-Graphyne is developed to create an active site for metallic decorations. For hydrogen storage, the calculated gravimetric capacity is 6.94 wt%, this result reaches DOE gravimetric targets (6.5 wt%). To measure the hydrogen bonding on the 18Li—γ-B-Graphyne structure, the average binding energies, and adsorption energies for each H 2 molecule are calculated, these values are between 0.321 and 0.353 eV, these values suggest that H 2 adsorption at ambient temperatures is possible. The calculations reveal that Li decoration improves the hydrogen storage conditions. Finally, employing adsorption isotherms calculations, the equilibrium pressure is determined for the 18Li—γ-B-Graphyne.