Ultrahigh-capacity reversible hydrogen storage in BN-biphenylene under environmental conditions

Although the use of two-dimensional materials for hydrogen storage has been intensively studied, finding reversible hydrogen storage material with high hydrogen gravimetric density under environmental conditions remains challenging. In this study, a new two-dimensional BN-biphenylene with Li decoration is systematically investigated through density functional theory (DFT) and grand canonical Monte Carlo (GCMC) simulations. The DFT results reveal that the average binding energy between Li and BN-biphenylene monolayers can be significantly improved from \ensuremath{-}0.9 eV to \ensuremath{-}3.34 eV by doping two C atoms at N sites. In this sense, each Li atom can adsorb three ${\mathrm{H}}_{2}$ molecules, yielding a high ${\mathrm{H}}_{2}$ weight density of 12.54 wt%. Meanwhile, considering the corresponding ${\mathrm{H}}_{2}$ desorption temperature at the ideal environmental condition of 323.89 K, Li-modified C-doped BN-biphenylene monolayer can be treated as a promising reversible candidate for high-density hydrogen storage. In addition, GCMC simulation results also prove that the ${\mathrm{H}}_{2}$ storage capacity of Li-modified C-doped BN-biphenylene can reach an ultrahigh 13.28 wt% under 298 K and 1 bar. The present study provides a positive and valuable reference for exploring ultrahigh-capacity reversible hydrogen storage materials under environmental conditions.