Hydrogen storage in alkali-metal-decorated organic molecules

We investigate the feasibility of alkali-metal (AM)-decorated organic molecules for hydrogen storage using first-principles density functional calculations. The present studies indicate that AMs bind strongly to some organic molecules, and Li-doped organic molecules exhibit a higher storage capacity (>10 wt %) than Na or K. The adsorption energies of dihydrogen on Li-decorated organic molecules are in the range of 10-30 kJ/mol, acceptable for reversible H(2) adsorption/desorption near room temperature. Regarding the H(2) adsorption mechanism, it is demonstrated that the dipole originating from the charge transfer within the AM-organic molecule complex induces a dipole in the H(2) molecule. (C) 2008 American Institute of Physics.