Theoretical Predictions on Li-Decorated Borophenes as Promising Hydrogen Storage Materials

Abstract

The experimental realization of two-dimensional borophene provides attractive alternates for hydrogen storage. In this work, we theoretically investigated the metal binding and hydrogen storage performance of the experimentally observed β12 and χ3 borophene by density functional theory (DFT) calculations. The calculation results on adsorption and diffusion of metal adatoms on β12 and χ3 borophene demonstrate that Li possesses the best adsorption performance on the borophenes, and simultaneous binding of two Li on both sides of borophene leads to stronger binding of Li. For the Li decorated borophenes, up to 5 H2 molecules can be adsorbed around one Li atom, with a moderate average adsorption energy range around 0.40 eV/H2. The maximum gravimetric density of H2 can reach 8.76 wt% for Li decorated β12 borophene and 10.79 wt% for Li decorated χ3 borophene. Our researches predicted the great potential of Li decorated β12 and χ3 brophenes as hydrogen storage materials.