Theoretical investigation of hydrogen storage in metal-intercalated graphitic materials

TL;DR

This paper uses first-principles calculations to explore how metal atoms in layered graphitic materials influence hydrogen storage, highlighting the potential of alkaline earth metals like Be and Mg to improve storage capacity.

Contribution

It provides a theoretical analysis of metal-intercalated graphitic materials, identifying specific metals that enhance hydrogen binding for storage applications.

Findings

Alkaline earth metals like Be and Mg can bind 3-4 H2 molecules.

Binding energies per H2 are in the 0.2--0.7 eV range.

Alkali and transition metals are less effective for storage enhancement.

Abstract

We have used first-principles methods to investigate how metal atoms dispersed in the interlayer space of graphitic materials affect their hydrogen-binding properties. We have considered ideal stage-one metal-intercalated graphites of various compositions as representative model systems. Our calculations suggest that alkaline earth metals can significantly enhance the hydrogen storage properties: for example, Be and Mg atoms would act as binding sites of three or four hydrogen molecules, with binding energies per H$_2$ in the 0.2--0.7 eV range, as required for applications. We also find that alkali and transition metals are not as effective in enhancing the storage capacity.