Capacity enhancement of polylithiated functionalized boron nitride nanotubes: an efficient hydrogen storage medium

摘要

By using first principles density functional theory simulations, we report detailed geometries, electronic structures and hydrogen (H-2) storage properties of boron nitride nanotubes (BNNTs) doped with selective polylithiated molecules (CLi2). We find that unsaturated bonding of Li-1s states with BNNT significantly enhances the system stability and hinders the Li-Li clustering effect, which can be detrimental for reversible H(2)storage. The H(2)adsorption mechanism is explained on the basis of polarization caused by the cationic Li(+)of CLi(2)molecules bonded with BNNT. The incident H(2)molecules are adsorbed with BNNT-nCLi(2)through electrostatic and van der Waals interactions. We find that with a maximum of 5.0% of CLi(2)coverage on BNNT, an H(2)gravimetric density of up to 4.41 wt% can be achieved with adsorption energies in the range of -0.33 eV per H-2, which is suitable for ambient condition H(2)storage applications.