2D Inorganic Biphenylene: Exploring Reversible Hydrogen Storage Capacity and Environmental Dependence

Traditional hydrogen storage methods rely on high-pressure or cryogenic conditions, which limit their practical applicability. The emergence of 2D materials has opened new avenues for physical adsorption-based hydrogen storage. Herein, we systematically investigate the hydrogen storage performance and environmental adaptability of 2D inorganic biphenylene (I-BPN) using first-principles and semiempirical calculations. Key results demonstrate that the pristine I-BPN monolayer exhibits excellent mechanical and thermodynamic stability, with hydrogen adsorption energies falling within the range characteristic of physisorption. It achieves a gravimetric hydrogen storage density of 10.78 wt % and a volumetric density of 132.37 g/L, competitive with state-of-the-art 2D hydrogen storage materials. Moreover, the application of an external electric field enhances H₂ adsorption, indicating a tunable storage capacity. The semiempirical method is employed to investigate the binding and release capabilities of H₂ molecules within the operational temperature and pressure parameters. It is found that the unmodified I-BPN monolayer possesses a remarkable reversible hydrogen storage capacity of 10.02 wt %, outperforming many other 2D materials with the same elemental compositions or similar structures. These findings highlight that the pristine I-BPN monolayer is a promising candidate for low-cost, high-efficiency hydrogen storage, offering the potential for advancing practical hydrogen energy applications.