MgScH15: A highly stable cluster for hydrogen storage

Abstract

Mg-Sc-H systems exhibit superior stability and high hydrogen storage capacity among the large class of magnesium-based hydrogen storage materials, but the underlying mechanisms for their outstanding hydrogen storage properties remain largely unexplored and require further investigation. Here, we have performed a comprehensive investigation on the structural evolution of MgScHn (n = 10–20) clusters by unbiased Crystal structure AnaLYsis by Particle Swarm Optimization (CALYPSO) method combined with density functional theory (DFT) optimizations at the B3PW91/6-311 + G(d) level. Our results show that the MgScH15 cluster with Cs symmetry is found to be the most stable cluster with good hydrogen storage capacity of 17.8 wt% due to the strong interaction among the 1s orbitals of the H atoms, the 2p orbitals of the Mg atom and the 3d orbitals of the Sc atom. The present findings are promising for further exploring novel hydrogen storage nanomaterials.