A first-principles study of hydrogen storage on pristine and Li-decorated aluminium monolayer

Hydrogen storage is a major challenge for the development of hydrogen energy technology, and this has inspired the search for novel materials with high storage capacity and reversibility. In this work, we study the use of pristine and Li-decorated metallic honeycomb aluminium monolayer for hydrogen storage, using density functional theory based methods. Our findings reveal that the hydrogen adsorption energies are significantly improved upon Li decoration, from an average of −0.045 eV for pristine monolayer to an average of −0.18 eV. Further, the Li-decorated monolayer can adsorb up to 3H2 molecules per Li atom, and the binding remains almost constant for different adsorbing sites for the Li atom. Additionally, we studied the impact of pressure and temperature on the hydrogen storage capability of the decorated monolayer and found that all of the H2 molecules adsorbed on the monolayer are stable at mild pressure at room temperature. The DOE's target of 5.5 wt % for hydrogen gravimetric densities in 2025 may be exceeded as a result of the metal decoration on both sides of the monolayer. Our results highlights Li-decorated low-cost metallic Aluminum sheets as potential candidates for hydrogen storage.