DFT Study of Planar Boron Sheets: A New Template for Hydrogen Storage

TL;DR

This study explores the potential of planar boron sheets as a novel template for hydrogen storage, demonstrating enhanced binding energies and capacities when alkali metals are dispersed on the sheets, especially lithium.

Contribution

It introduces the use of planar boron sheets as a new platform for hydrogen storage, showing improved properties over graphene and detailed analysis of alkali metal dispersion effects.

Findings

Boron sheets have stronger hydrogen binding than graphene.

Dispersion of alkali metals increases hydrogen storage capacity.

Boron-Li system can store up to 10.7 wt.% hydrogen.

Abstract

We study the hydrogen storage properties of planar boron sheets and compare them to those of graphene. The binding of molecular hydrogen to the boron sheet (0.05 eV) is stronger than that to graphene. We find that dispersion of alkali metal (AM = Li, Na, and K) atoms onto the boron sheet markedly increases hydrogen binding energies and storage capacities. The unique structure of the boron sheet presents a template for creating a stable lattice of strongly bonded metal atoms with a large nearest neighbor distance. In contrast, AM atoms dispersed on graphene tend to cluster to form a bulk metal. In particular the boron-Li system is found to be a good candidate for hydrogen storage purposes. In the fully loaded case this compound can contain up to 10.7 wt. % molecular hydrogen with an average binding energy of 0.15 eV/H2.