DFT study of superlight ambient temperature reversible H2 storage media based on Li decorated on new planar BCN

Abstract

A novel 2D pm-BCN monolayer with unique porous geometry, superlight mass, and superior stability is a promising candidate for hydrogen storage. However, pure 2D materials suffer from the weak Van de Waals interaction between the H2, and modification becomes necessary to improve their performance. Here, we design a new complex by decorating active Li ions on the 2D pm-BCN substrate. The decoration of Li can transfer a partial electron to the substrate pm-BCN, which enhances the original π bonding among pm-BCN and induce more active sites on it. Both Li and BCN can act as the adsorption sites. The H2 can realize reversible adsorption under an ambient condition with average adsorption energy of −0.20 eV/H2 and a gravimetric capacity of 6.34 wt%, which surpasses the targe value set by U.S. Department of Energy (DOE). Rigorous analysis of its electronic properties, including a partial density of states, charge density, and crystal orbital overlap population, illustrates that the polarization mechanism contributes to the enhancement of the hydrogen storage capacity of Li@pm-BCN.