DFT study of Mg decorated on the planar B2N as a novel hydrogen storage media

Abstract

Developing a compelling storage medium is essential for wide application of clear energy hydrogen to alleviate the environment and energy crisis, and design novel materials is the key solution for this challenge. In this paper, we designed a new complex by decorating alkaline earth metal Mg ions on new planar B2N monolayer. The Density functional theory calculation were performed to examine the geometries, electronic structures, thermodynamic property and hydrogen storage performance of the complex. We found charge transfer and polarization effect is critical for the improvement. Partial charges from Mg were transferred to the pristine B2N monolayer, making it more electropositive, which is favorable for hydrogen storage due to enhanced electrostatic interactions between the complex and H2. The configurations of the Mg-decorated B2N with multiple adsorbed H2 molecules were clarified in this study, and the highest loading of per unit is 70 H2, with adsorption energies ranging from −0.391 eV to −0.106 eV. Its highest gravimetric capacity can reach 8.16 wt%, outstripping the target value of 5.5 wt% set by the U.S. department of energy (DOE). The computational result of our study indicates a promising prospect for alkali metal functionalized superlight planar B2N materials in reversible clean energy storage.