Theoretical Study of Li-Doped sp2–sp3 Hybrid Carbon Network for Hydrogen Storage

Nanoporous carbon structures are promising candidates for hydrogen physisorption storage due to their high specific area and light weight. Using first-principles calculations, we predict a type of sp 2 –sp 3 hybrid carbon network (HCN) with well-aligned and size-tunable nanopores that are suitable for hydrogen storage. The unique shape of the nanopores is beneficial for the selective Li atoms doping and induces an enhanced H 2 binding energy that can be attributed to the improved interaction between polarized H 2 and Li ion. A maximum weight percentage of hydrogen storage reaches 6.28 wt % with an average binding energy of −0.19 eV in Li-doped HCN. Together with the ultrahigh volumetric density of hydrogen (102 g/L), the HCN structure is a promising candidate for the hydrogen storage medium.