title: Metal-functionalized silicene for efficient hydrogen storage.
abstract: First-principles calculations based on density functional theory are used to investigate the electronic structure along with the stability, bonding mechanism, band gap, and charge transfer of metal-functionalized silicene to envisage its hydrogen-storage capacity. Various metal atoms including Li, Na, K, Be, Mg, and Ca are doped into the most stable configuration of silicene. The corresponding binding energies and charge-transfer mechanisms are discussed from the perspective of hydrogen-storage compatibility. The Li and Na metal dopants are found to be ideally suitable, not only for strong metal-to-substrate binding and uniform distribution over the substrate, but also for the high-capacity storage of hydrogen. The stabilities of both Li- and Na-functionalized silicene are also confirmed through molecular dynamics simulations. It is found that both of the alkali metals, Li(+) and Na(+), can adsorb five hydrogen molecules, attaining reasonably high storage capacities of 7.75 and 6.9 wt %, respectively, with average adsorption energies within the range suitable for practical hydrogen-storage applications.
authors.affiliation: Condensed Matter Theory Group, Department of Physics and Astronomy, Box 516, Uppsala University, S-75120 Uppsala (Sweden). tanveer.hussain@physics.uu.se.
authors.forename: Tanveer
authors.initials: T
authors.lastname: Hussain
authors.forename: Sudip
authors.initials: S
authors.lastname: Chakraborty
authors.forename: Rajeev
authors.initials: R
authors.lastname: Ahuja
keywords: charge transfer; density functional calculations; hydrogen storage; hydrogenation; silicene