Lithium decorated ψ-graphene as a potential hydrogen storage material: Density functional theory investigations

In the present scenario, hydrogen has become a prominent alternative of fossil fuel that motivated us to develop more advanced nanomaterials to store efficient hydrogen for future use. This paper studies the hydrogen storage performance of Li-decorated psi-graphene by conducting density functional theory simulations involving van der Waals corrections. Psi (psi)-graphene is an advanced two-dimensional carbon allotrope that comprises pentagon, hexagon, and heptagon carbon rings. The simulation outcome reveals that the Li atom is bounded strongly to psi-graphene with -2.63 eV binding energy through 0.89e charge transfer fromLi-2s orbital to C-2p orbitals psi-graphene system decorated with the Li atom can bind seven hydrogen molecules with a suitable average binding energy of 0.31 eV/H-2, high H-2 gravimetric capacity of 15.15 wt%, and optimal average desorption temperature of 384 K. As per the Bader charge portioning, similar to 0.09e charge is transferred from the Li-2s orbital to the H-1s orbital after hydrogen adsorption on Li + psi-graphene. The hydrogen molecules are adsorbed on Li + psi-graphene via a polarization mechanism. The high Li diffusion barrier of 0.78 eV and structural integrity of Li + psi-graphene configuration at high temperature predicts that the system is a suitable candidate for high-capacity hydrogen storage applications. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study investigates the hydrogen storage performance of Li-decorated psi-graphene using density functional theory simulations. The results show that Li atoms strongly bind with psi-graphene, allowing for the binding of multiple hydrogen molecules with suitable binding energy, high gravimetric capacity, and optimal desorption temperature. The Li-decorated psi-graphene demonstrates potential for high-capacity hydrogen storage applications.