▎ 摘　　要

Based on first-principles density functional theory, we show that Li-doped B2C graphene can serve as a high-capacity hydrogen storage medium with the gravimetric density of 7.54 wt %. The present results indicate that the strong binding of Li onto the substrate comes from the hybridizations of B 2p and C 2p orbitals with the partial occupancy of Li 2p orbitals. Both the polarization mechanism and the orbital hybridizations contribute to the adsorption of H-2 molecules and the resulting adsorption energy is in the range of 0.12-0.22 eV/H-2. The system reported here is favorable for the reversible hydrogen adsorption/desorption at the room temperature. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3583465]