Enhanced hydrogen storage properties of light metals dispersed boron hydride monolayer

Abstract

<p>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.<p>