High-Capacityand Reversible Hydrogen Storage in an Intrinsic Li₃B₂N₂ Monolayer

Hydrogen is widely considered a promising clean energy carrier because of its high energy density and environmental benignity, yet the development of safe and reversible hydrogen storage materials remains a major challenge. Two-dimensional materials are particularly attractive for this purpose owing to their large specific surface area, fully exposed active sites, and highly tunable electronic structures. Here, using crystal structure prediction combined with first-principles calculations, we predict a stable metallic Li₃B₂N₂ monolayer as a potential hydrogen storage material. This monolayer can adsorb up to six H₂ molecules per unit cell with an average adsorption energy of ∼0.23 eV/H₂, yielding a high hydrogen storage capacity of ∼7.8 wt.%. Further analysis reveals that hydrogen adsorption is governed by the synergistic effects of electrostatic polarization and orbital hybridization. Moreover, calculations on the temperature- and pressure-dependent hydrogen storage behavior show that all hydrogen-adsorbed structures remain stable at room temperature under a pressure of 3.7 MPa. The van't Hoff analysis indicates that the maximum desorption temperature at atmospheric pressure is 316 K, suggesting favorable reversibility under near-ambient conditions. These results establish Li₃B₂N₂ as a promising intrinsic two-dimensional material for high-density and reversible hydrogen storage.