First-principles calculations of Li-decorated Dirac semimetal NP monolayer as a potential reversible hydrogen storage medium

Abstract

To explore the potential applications of the recently proposed two-dimensional (2D) Dirac material, the NP monolayer, the hydrogen storage properties of a Li-decorated NP monolayer were calculated using first-principles methods. DFT calculation results revealed that a Li atom can stably bind to the surface of the NP monolayer and, in turn, is able adsorb two H2 molecules that exhibit a suitable adsorption energy (-0.20 eV/H2). As such, a hydrogen storage gravimetric density of 5.5 wt% may be achieved in the fully Li-decorated NP system (18H2-Li12N12P12). Further, MD simulations demonstrated that the H2 adsorbed on the Li12N12P12 surface were released at 300 K, and the reusability of this material was promoted by its excellent structural stability. These findings give a theoretical basis for the potential hydrogen storage application of the Li-decorated NP monolayer.