Superalkali–Superhalogen Complexes as Versatile Materials for Hydrogen Storage: A Theoretical Study

Abstract

In the present work, we have studied superhalogen (Al13)–superalkali (M3O, M = Li, Na, and K) assemblages as versatile materials for hydrogen storage. In the present study, we suggest an interesting material to form a sets of typical donor–acceptor frameworks with high hydrogen storage performance via linking the superalkalis M3O to the superhalogen Al13. Our density functional theory (DFT) calculations reveal that the band gap energy of Al13 is decreased by attaching of the M3O superalkalis. Also, we found that the M3O species lowered the band gap energy of Al13 by more than 32% and converted it to an n-type semiconductor. Hydrogen adsorption on Al13–M3O (M = Li, Na, and K) is explored by DFT calculations and the results are compared with the hydrogen adsorption on the Al13–M (Li, Na, and K) systems. We found that the Al13–M3O systems show higher hydrogen storage performance as compared to the Al13–M systems. In fact, the Al13–M3O with three alkali metals show high-capacity hydrogen storage than the Al13–M systems. Among the six Al13–M and Al13–M3O systems, the maximum adsorption energy and the higher capacity hydrogen storage is related to the hydrogen adsorption on the Al13–Li3O. Our study exhibits that the Al13–Li3O is a promising material for hydrogen storage.