Enhanced hydrogen storage properties of light metals dispersed boron hydride monolayer

Abstract

Using first-principles calculations, we explore the potentials of boron hydride (BH) for hydrogen (H2) storage. Lithium (Li) and potassium (K) dopants enhance the H2 storage capabilities of BH. The binding energies of Li, and K are found as −2.65 and −1.69 eV, respectively, indicating a strong binding. Ab initio molecular dynamic (AIMD) simulations at 400 K provide insights into the thermal stability of Li-, and K-doped BH. Notably, H2 molecule adsorptions on metal-decorated BH result in substantial binding energies of −0.45 and −0.29 eV/H2 for Li, and K, respectively. Under layered adsorption, the BH–4Li (BH–4K) accommodates up to 38H2 (34H2) molecules, boasting an impressive gravimetric density of 26.46 (16.57) wt.%. Even a single layer of H2 over BH–4Li, and BH–4K corresponds to 11.70 wt% and 7.56 wt%, respectively. Adsorption mechanism of H2 could be tuned under the influence of stress and strain. Additionally, thermodynamic analysis based on Langmuir model is employed to elucidate the H2 storage capabilities under practical conditions of temperature and pressure.