Enhanced hydrogen storage on Li-doped defective graphene with B substitution: A DFT study

The characteristics of hydrogen adsorption on Li-doped defective graphene systems were investigated using density functional theory (DFT) calculations. Four types of defective structures were selected. Li atoms were well dispersed on the defective graphene without clustering, evidenced by the binding energy value between Li and defective graphene than that of Li-Li-x. Additionally, as the amount of adsorbed H-2 molecules increase, the H-2 molecules show tilting configuration toward the Li adatom. This is beneficial for more hydrogen adsorption under the electrostatic interaction. On these four stable structures, there were up to three polarized H-2 molecules adsorbed on per Li adatom, with the average hydrogen adsorption energy in the range of approximately 0.2-0.4 eV. These results provide new focus on the nature of Li-doped defective graphene with sometimes B substitution medium, which could be considered as a promising candidate for hydrogen storage. (C) 2017 Elsevier B.V. All rights reserved.