Lithium-Decorated Borospherene B: A Promising Hydrogen Storage Medium.

The recent discovery of borospherene B marks the onset of a new kind of boron-based nanostructures akin to the C buckyball, offering opportunities to explore materials applications of nanoboron. Here we report on the feasibility of Li-decorated B for hydrogen storage using the DFT calculations. The B cluster has an overall shape of cube-like cage with six hexagonal and heptagonal holes and eight close-packing B triangles. Our computational data show that Li&B(1-3) complexes bound up to three H molecules per Li site with an adsorption energy (AE) of 0.11-0.25 eV/H, ideal for reversible hydrogen storage and release. The bonding features charge transfer from Li to B. The first 18 H in Li&B(3) possess an AE of 0.11-0.18 eV, corresponding to a gravimetric density of 7.1 wt%. The eight triangular B corners are shown as well to be good sites for Li-decoration and H adsorption. In a desirable case of Li&B-42 H(8), a total of 42 H molecules are adsorbed with an AE of 0.32 eV/H for the first 14 H and 0.12 eV/H for the third 14 H. A maximum gravimetric density of 13.8 wt% is achieved in 8. The Li-B-nH system differs markedly from the previous Li-C-nH and Ti-B-nH complexes.