High-capacity hydrogen storage using Li-decorated Li2P sheet

Using density functional theory, we investigate the hydrogen storage capacity of Li-adsorbed lithium porphyrin sheet (Li2P·2Li). We show that the central Li atom (Lic) and the decorated one (Lid) can bind four or three H2 molecules, respectively. Due to the polarization of hydrogen molecules under the electric field generated by the positively charged Lic (Lid), the binding energy of the H2 molecules is between 0.12 eV and 0.22 eV, which is beneficial for the storage and release of the H2 molecules. The moderate binding energy and large hydrogen storage capacity (7.95 wt%) indicate that Li2P·2Li is a promising hydrogen storage material.