Using first principles study, we have investigated the hydrogen storage capacity of Ca-coated B-40. Our result shows that Ca prefers to adsorb on the top hollow center of heptagonal ring of B-40 due to the large binding energy of 2.820 eV. Bader charges calculation indicates that charges transfer from Ca to B-40 result in an induced electric field so that H-2 molecules are polarized and adsorbed onto the surface of B-40 without dissociation. The Ca6B40 complex can adsorb up to 30 H-2 molecules with average adsorption energy of 0.177 eV/H-2 and the hydrogen storage gravimetric density reaches up to 8.11 wt.%, higher than the goal from DOE by the year 2020. These findings will suggest a new and potential structure for hydrogen storage in the future. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.