Chemical engineering of adamantane by lithium functionalization: A first-principles density functional theory study

TL;DR

This study uses first-principles density functional theory to explore how lithium-functionalized adamantane can be used for efficient hydrogen storage, showing promising gravimetric capacity and stability.

Contribution

It demonstrates that lithium functionalization activates adamantane for high-capacity hydrogen storage with detailed stability analysis.

Findings

Hydrogen storage capacity of ~7.0% gravimetric weight.

Average binding energy of ~ -0.15 eV/H2 for adsorbed hydrogen.

Structural stability confirmed by vibrational spectra and MD simulations.

Abstract

Using first-principle density functional theory, we investigated the hydrogen storage capacity of Li functionalized adamantane. We showed that if one of the acidic hydrogen atoms of adamantane is replaced by Li/Li+, the resulting complex is activated and ready to adsorb hydrogen molecules at a high gravimetric weight percent of around ~ 7.0 %. Due to polarization of hydrogen molecules under the induced electric field generated by positively charged Li/Li+, they are adsorbed on ADM.Li/Li+ complexes with an average binding energy of ~ -0.15 eV/H2, desirable for hydrogen storage applications. We also examined the possibility of the replacement of a larger number of acidic hydrogen atoms of adamantane by Li/Li+ and the possibility of aggregations of formed complexes in experiments. The stabilities of the proposed structures were investigated by calculating vibrational spectra and doing MD simulations.