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

In the present work, we have studied superhalogen (Al 13 )–superalkali (M 3 O, 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 M 3 O to the superhalogen Al 13 . Our density functional theory (DFT) calculations reveal that the band gap energy of Al 13 is decreased by attaching of the M 3 O superalkalis. Also, we found that the M 3 O species lowered the band gap energy of Al 13 by more than 32% and converted it to an n-type semiconductor. Hydrogen adsorption on Al 13 –M 3 O (M = Li, Na, and K) is explored by DFT calculations and the results are compared with the hydrogen adsorption on the Al 13 –M (Li, Na, and K) systems. We found that the Al 13 –M 3 O systems show higher hydrogen storage performance as compared to the Al 13 –M systems. In fact, the Al 13 –M 3 O with three alkali metals show high-capacity hydrogen storage than the Al 13 –M systems. Among the six Al 13 –M and Al 13 –M 3 O systems, the maximum adsorption energy and the higher capacity hydrogen storage is related to the hydrogen adsorption on the Al 13 –Li 3 O. Our study exhibits that the Al 13 –Li 3 O is a promising material for hydrogen storage.