Theoretical limit of reversible hydrogen storage capacity for pristine and oxygen-doped boron nitride

Abstract

To achieve higher hydrogen storage capacity than that of compressed gas vessels, new advanced materials must be developed. Among the most promising are two-dimensional layered nanomaterials, such as graphene and boron nitride, storing hydrogen via physisorption which is potentially reversible at relatively low pressures. Unlike graphene, boron nitride is a polar material that makes it potentially more attractive for hydrogen physisorption. To quickly evaluate storage capacity of novel materials an efficient theoretical tool is proposed. A customized model combining quantum simulation with thermodynamic calculation is developed and applied for pristine and oxygen-doped boron nitride materials. It is shown that pristine boron nitride has a maximum reversible hydrogen storage capacity of 1.5 wt.% under 5 MPa at room temperature. Oxygen doping increases the capacity to 1.9 wt.% under the same conditions by deepening and widening the adsorption potential. Both gravimetric and volumetric storage properties are found to be strong functions of the interlayer separation distance of the material, with an optimum distance near 7 Å. The present results indicate that pristine and oxygen doped boron nitride materials have a suitable base configuration for potentially high reversible hydrogen storage.