A DFT-D3 investigation on Li, Na, and K decorated C6O6Li6 cluster as a new promising hydrogen storage system.

Because of the increasing demand for energy sources, searching for reversible and high-capacity hydrogen storage materials plays a vital role in the extensively utilizing of hydrogen as a clean energy source. In this study, dispersion-corrected density functional theory (DFT-D3) calculations are utilized to examine the possibility of storing H 2 molecules on Li, Na, and K alkali metals decorated C 6 O 6 Li 6 cluster. To evaluate H 2 adsorption capability, the adsorption energies, electron density difference iso-surfaces, and charge-transfers are calculated and discussed. The results indicate that a hydrogen molecule is physisorbed on the Li@C 6 O 6 Li 6 , Na@C 6 O 6 Li 6 , and K@C 6 O 6 Li 6 with average adsorption energies of −0.264, −0.150, and −0.109 eV, respectively. Double-sided alkali metal atoms decoration can lead to the maximum gravimetric density of 15.68, 14.49, and 13.79 wt% for 2Li@C 6 O 6 Li 6 –8H 2 , 2Na@C 6 O 6 Li 6 –10H 2 , and 2K@C 6 O 6 Li 6 –12H 2 complexes, respectively. Finally, desorption temperatures reveal that the systems can operate as reversible hydrogen storage materials. [Display omitted] • Alkali metal decorated C 6 O 6 Li 6 cluster for hydrogen storage using DFT-D3 calculations. • Double alkali metal decorated C 6 O 6 Li 6 cluster shows maximum gravimetric density above 10.00 wt%. • Adsorption capacities and desorption temperatures confirm H 2 storage reversibility. [ABSTRACT FROM AUTHOR]