Hydrogen Storage on Metal-Coated B80 Buckyballs with Density Functional Theory

We investigate the feasibility of bare and metal-coated boron buckyball B-80 with M = Li, Na, K, Be, Mg, Ca, Sc, Ti, and V for hydrogen storage using density functional theory approach. We find that M = Ca or Sc are best candidates for hydrogen storage with moderate adsorption energy of H-2 and with clustering of Sc or Ca on B-80 surface avoided. We further address that an isolated cluster Ca12B80 (SC12B80) can bind up to 66 (60) H-2 molecules with an average binding energy of 0.096 (0.346) eV/H-2, leading to a hydrogen storage capacity of 9.0 wt % (7.9 wt %). Two adsorption mechanisms, charge-induced dipole interaction and the Dewar-Kubas interaction, are demonstrated, and they are responsible for high hydrogen storage capacity of Ca12B80 and SC12B80. Most interestingly, the hydrogen loaded B80Sc12-48H(2) complex can further adsorb 12 H-2 through charge-induced dipole interaction. In other words, these two mechanisms dominate the adsorption of different parts of H-2 in the same cluster of SC12B80-60H(2).