Hydrogen storage in pillared Li-dispersed boron carbide nanotubes

TL;DR

This study uses ab initio density-functional theory to demonstrate that pillared Li-dispersed boron carbide nanotubes can store hydrogen efficiently with high density and stability, suitable for practical applications.

Contribution

It introduces a novel boron substitution strategy that enhances lithium binding and hydrogen storage capacity in boron carbide nanotubes.

Findings

Hydrogen storage capacity exceeds 6.0 wt% and 45 g/L volumetric density.

Enhanced lithium binding energy (~2.7 eV) prevents lithium aggregation.

Hydrogen adsorption energies are suitable for reversible storage at room temperature.

Abstract

Ab initio density-functional theory study suggests that pillared Li-dispersed boron carbide nanotubes is capable of storing hydrogen with a mass density higher than 6.0 weight% 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 aggregation (or segregation) 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 and near ambient pressure.