Hydrogen storage in Li and Ti decorated borazine: A first-principles study

The capacity of hydrogen storage in alkali metal (Li, Na, or K), alkaline-earth metal (Be, Mg, or Ca), or Ti decorated borazine has been investigated by using the first-principles calculations based on density functional theory. Our results indicated that alkali metals could bind strongly to the inorganic molecule borazine and, especially, Li decorated borazine exhibits the highest hydrogen storage capacity up to 10.4 wt % theoretically. The adsorption energies of hydrogen molecules are in the range of −0.10∼−0.15 eV/H2 (−0.23∼−0.28 eV/H2 for local density approximation calculation) which are acceptable for reversible H2 adsorption/desorption near ambient temperature. We also found that the hydrogen storage capacity of Ti decorated borazine is about 7.2 wt %, less than that of the Li decorated system, but the adsorption energies are in the range of −0.16∼−0.24 eV/H2 due to the Kubas interaction, which is larger than that of the Li decorated borazine and the system is also suitable for reversible H2 adsorption/desorption near ambient temperature.