Si2BN monolayers as promising candidates for hydrogen storage.

Hydrogen storage properties of the pure Si2BN monolayer were studied using density functional theory calculations. The interaction of H2 molecules with the Si2BN monolayer is weak and of electrostatic nature. The average hydrogen adsorption energies are within the ideal range of practical applications (0.187-0.214 eV), and the consecutive adsorption energies indicate that the spontaneous adsorption of H2 molecules on the Si2BN monolayer can occur. The hydrogen gravimetric density of the periodic Si2BN monolayer reaches 8.5 wt%, which exceeds the standard of 6.0 wt% set by the US Department of Energy (DOE) by the year 2020. The estimated desorption temperatures show the desirable properties for the long term recycling of the Si2BN storage medium. Thus, our results show that the Si2BN monolayer is a promising candidate for molecular hydrogen storage.