Hydrogen Storage in Pillared Li-Dispersed Boron Carbide Nanotubes

Ab initio density-functional theory study suggests that pillared Li-dispersed boron carbide nanotubes are capable of storing hydrogen with a mass density higher than 6.0 wt% and a volumetric density higher than 45 g/L. The boron substitution in carbon nanotube greatly enhances the binding energy of Li atom to the nanotube, and this binding energy (∼2.7 eV) is greater than the cohesive energy of lithium metal (∼1.7 eV), preventing lithium from clustering at high lithium doping concentration. The adsorption energy of hydrogen on the Li-dispersed boron carbide nanotube is in the range of 10−24 kJ/mol, suitable for reversible H₂ adsorption/desorption at room temperature. The aim of this theoretical study is to stimulate future experimental tests on the hydrogen-storage capability in porous boron−carbon systems (e.g., microporous boron carbides) with sufficiently large interior surfaces coated with submonolayer lithium.