Hexagonal Boron Nitride (h-BN) Sheets Decorated with OLi, ONa, and Li 2 F Molecules for Enhanced Energy Storage.

First-principles electronic structure calculations were carried out on hexagonal boron nitride (h-BN) sheets functionalized with small molecules, such as OLi, ONa, and Li2 F, to study their hydrogen (H2 ) storage properties. We found that OLi and ONa strongly adsorb on h-BN sheets with reasonably large inter-adsorbent separations, which is desirable for H2 storage. Ab initio molecular dynamics (MD) simulations further confirmed the structural stability of OLi-BN and ONa-BN systems at 400 K. On the other hand, Li2 F molecules form clusters over the surface of h-BN at higher temperatures. We performed a Bader charge investigation to explore the nature of binding between the functionalized molecules and h-BN sheets. The density of states (DOS) revealed that functionalized h-BN sheets become metallic with two-sided coverage of each type of molecules. Hydrogenation of OLi-BN and ONa-BN revealed that the functionalized systems adsorb multiple H2 molecules around the Li and Na atoms, with H2 adsorption energies ranging from 0.20 to 0.28 eV, which is desirable for an efficient H2 storage material.