Design of metal-decorated beryllium carbide (Be2C) as a high-capacity hydrogen storage material with strong adsorption characteristics

Advanced research to design new two-dimensional materials with high capacity and efficient reversibility is one of the essential strategies for developing hydrogen storage applications. By employing density functional theory (DFT) and ab-initio molecular dynamic (AIMD) calculations comprising van der Waals interactions, we systematically studied the structural stability, electronic properties and the hydrogen storage properties of the pure beryllium carbide (Be2C) monolayer. Our results demonstrate that binding energies of H-2 molecules in this system are exactly located in the desirable energy range. Furthermore, the stabilization of hydrogen by metal decoration of Be2C on both sides was improved in comparison to that of pristine Be2C. 2Li@Be2C and 2K@Be2C were able to host up to 16 molecules of hydrogen reaching a gravimetric capacity of 10.21 and 8.48 wt %, respectively. The desorption temperature (T-D) was found much higher than the critical point of hydrogen. In addition, the T-D estimates were validated by AIMD simulations of hydrogenated Li@Be2C and K@Be2C. Thus, the Li/K@Be2C system can be a promising candidate for the experimental setup for hydrogen storage.