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

Abstract

We investigate the feasibility of bare and metal-coated boron buckyball B80 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 H2 and with clustering of Sc or Ca on B80 surface avoided. We further address that an isolated cluster Ca12B80 (Sc12B80) can bind up to 66 (60) H2 molecules with an average binding energy of 0.096 (0.346) eV/H2, 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 B80Sc12−48H2 complex can further adsorb 12 H2 through charge-induced dipole interaction. In other words, these two mechanisms dominate the adsorption of different parts of H2 in the same cluster of Sc12B80−60H2.